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{{#Wiki_filter:Niagara Mohawk Nine Mi>e point Unit 2 Event of 13 August ]991 Report by:    Melvin L. Crensbam Consulting Engineer Po~er Systems Engineeriag Department General Electric Company Schenectady, NY 8 September  1991
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5 iagara Mohawk 5 ine Mile Point Unit                          2 E vent of 13 August 1991 05:4S Qn August 13, 1991, at 5:48    Abf the Unit 2 phase B generator step-up transtormer failed. Oscillographic records of the event are available from a digital data recorder at the Scriba Substation. They show various 345 kV and 11 5 k V system voltages and currents. Figure A with notations is attached.
The four cycles preceding the fault show no signs of a gradual degradation or a developing disturbance. The oscillographic traces and station protective relay targets reported, indicate a ground fault occurred on the high voltage winding.
Depression of the 345 kV phase 8 bus voltage to about 39% of the prior value was observed from the oscillographic trace. This suggests the involvement of only a portion of the entire winding. The 345 kV line currents and voltages show rapid development of the ground fault beginning at point 1 with the ground current reaching a constant value of 1,300 amperes in 1 1/2 cycles at point 4, The flashover in the faulted transformer occurs just preceding a maximum in phase 2 to neutral voltage (as would have been expected) at point 2. The 345 kV line current in an unfaulted phase increases in step function manner to 350/o of the prefault value at point 3, No high speed recordings of voltages or currents within the plant were available. No sequence of event recordings were available to correlate relay operation times. Due to the large amount of magnetic energy coupling the generator rotor and stator, and known electrical parameters, thc decay of fault current contributed by the generator to the solidly connected transformer would have spanned a number of seconds as thc field decayed.
Relay operation targets reported were:
: l. Transformer Differential Relay (Type BDD) on Transformer 2MTX-XM1B.
: 2. Transformer Neutral Current Relay (Type      IAC).
: 3. Overall Unit Differential Relays (Type BDD) in phases 2 and 3.
: 4. Generator Phase Overcurrent Relays (Type PJC) in phases 2 and 3.
 
r Fv Following isolation of the generator and failed transformer from the power grid, marked 5 on Figure A. only a single 345 kV phase to ground voltage record is available. The magnitude of this voltage on an unfaulted phase is 74fo of the pre-fault value. Since generator neutral current is limited to less than 8 amperes. it is known that the faulted transformer appears as a line to line fault with some impedance to the generator. By trial and error calculation, generator.
line currents are found to be 0, 1.9 and 1.9, multiples of the rated value of 31,140 amperes. The line-to-line voltages have magnitudes 74 lo 74 lo, and 25%
of the rated value of 25,000 volts. The decay of this voltage for 0.2S seconds of the recording has a measured time constant of 2.7 seconds. The calculated value of the impedance of the faulted transformer as seen by the generator is 0.23 per unit.
Conditions prevailing during the six cycle time period following the fault, marked 2 on Figure A, cannot be determined with certainty. The exact nature of the fault within the transformer is not known and the physical evidence will be strongly affected by the continued flow of energy from the generator due to the inherent time constant. The flashover of only a portion of the HV winding is evident since the 345 line voltages to neutral remain at 39%o, 867o and 86'1o of the pre-fault values. The presence of "residual" in the measured 345 kV line currents provides the evidence of transformer neutral to ground current. This requires that the fault involves a path for current to ground from the high voltage winding. Recorded voltages and currents show a step change to new values and no dramatic change during the time period of the record, which totals somewhat less than 1/2 second. It could be said they are "cleaner" and less distorted than commonly seen oscillograph recordings of faults.
Given these observations and since both the generator and the system were supplying fault current into the faulted transformer, generator line-to-line voltages preceding isolation would be expected to be greater than those immediately following isolation.
It has been speculated that very high frequency energy (mHz region) may have causal malfunction of logic and control circuitry in the UPS equipment. A broad-range of frequencies would be expected in any arcing phenomenon such as occurred in this fai1ure. Nothing in the available data or design parameters of the plant equipment would suggest an extraordinary generation or propagation of higher frequency components. 'Ihe failure of a transformer and internal arcing is not a rare occurrence. Comparison of oscillographic charts
 
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from similar events in other plants show nothing unexpected or unusual in this particular failure. It must be borne in mind that the sampling rate of the recorder is listed as 5.814 kHz and frequency components in excess of perhaps 500 Hz would not be accurately portrayed.
GE experience in testing of typical power transformers (such as the Lnit Auxiliaries Transformers) provides an indication of the expected coupling between windings at radio frequencies in the region of 1 megahertz: The attenuation factors range from 1,000: 1 to 10's of thousands: 1. Direct measurements could be made in this plant to determine attenuation factors for individual transformers over a range of frequencies. These tests would be made on non-energized transformers using an RF signal generator and a sensitive, calibrated detector.
Attached recent articles on electro-magnetic interference.          Reference 1 discusses IEC 801,4 and the characteristics of electrically fast transients.
Reference 2 discusses testing of ground connections.
V  i The possibility of elevation of thc station grounding system as a result of this disturbance was postulated. The relatively high level of ground fault current, estimated at 1,300 ampercs from the available recording, would not have been conducted into the plant. This current can only fiow in Rom the 345 kV system for the 6 cycle period required for relay and circuit breaker operation to achieve isolation. The generator ground current would have been limited to less than 8 ampcres by the neutral grounding equipmcnt. Elevation or differences in ground potential within the plant would therefore not have been expected during this event.
Reference 1 discusses the problem of achieving a "super" ground and concludes that a stable ground reference for interconnected equipment is of greater significance. Since normally circulating ground currents are not expected, testing with very low voltages and currents is recommended. Note especially the recommendation to test with a frequency non-harmonically related to the power line &equcncy.
The transformers stepping the voltage down to successively lower voltage levels are connected in a manner to minimize coupling of power frequency and higher frequency. components between thc various busses.                  Specific configurations are:
 
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: l. Normal Station Service Transformer-delta 25 kV to wye 13.8 kV with 400 ampere resistive grounding on the 13.8 kV side.
: 2. Load Center Transformers-delta 13.8 kV to wye 4.16 kU with  4R  ampere resistive grounding on the 4.16 kV side..
: 3. Load Center Transformers-delta 13.8 kV or 4.16 kV to wye 600 volts with neutral solidly grounded on the 600 volt side.
: 4. Reserve Station Service Transformers-wye 115 kV, delta 4.16 kV, wye 13.8 kV, The 13.8 kV neutral is 400 ampere resistive grounded. The 4.16 kV circuit is connected to a zig-zag grounding transformer with a resistor in the neutral connection, presumably for 400 amperes.
These configurations provide "effectively grounded" distribution busses as defined in TEE Standard 142 and will serve to limit transient over voltages.
This is in accordance with design practices deemed prudent and conservative within the power industry.
The industry continues to review the effects of geomagnetic disturbances on power transformers.
While no evidence is seen of voltage distortion in the four cycles preceeding the failure, excessive duty could have occurred if these transformers had been subjected to low level direct current previously. References 3 and 4 are attached for perusal.
 
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fncfustrfal Equfpment EISCtt'OfllCS                                Ill lndLIStl'Igf APPIiCatienS A Discussion of Fundamentaf ENlC Princfpfes for Electronic Controllers ln an industrial Environment By 4t'iHiam 0. Kimmel. PE Kimmei Gerke Associates, Ltd EDDIC problerrs i~:h:ndustra! ccnuois are      bances are a weH known    irdustral problem. cally a power disturbance prob'.em.:s: .
aggravated by harsh eni.ronments. mixed        In iac:. when a problem occurs. ke tirst      the car..er of residual eiiects of o-.
:ec.'".noiogies and a laclc of umform E!ifC    though': is:o blame the power company.        disturbances. Any 'ind;sinai or commer:
guidebnes. T:is arLicie '>el concentrate on    Often power quality is a problem (especially  suucture has sigiu8cant .'ow ~equen
    ;he common as;ec:s of electronic controls      if grounding issues are inciudedl. but the      currents circulating:hrough t.".e grou in an !ndustnal en>".ronment. which is        problem is almost always generated by          system. sometimes because the .nergy generally mucn harsher:ban the ofGce          adjacent equipment.                            intentionally dumped onto the ground (s.
envirOnmenL                                        Tradiuonal problems with power include      as with an arc weider) and someur..
What is the industrial enviroment and      spikes and transients, sags and surges, and    because of unintenuonal coupling or v what can be core about it! The environmen      outages. which threaten the eiectroiucs via    an inadvertent connection between neu includes the entire gamut of '.he basic        the power supply. These problems are            and ground somewhere in the!aciiity.
threats. power disturbances. RFI. and          fairly weil documented and are often solved        Radio Frequency Interference.        R ESD. RFI and power disturbances may be        using power conditioners or UPS.                dio frequency interfer~nce affects bo locally generated or not. Mixed technolo-          The most common power problems              analog and digital circuits. with ana'c gies compourd:he problem. Digital circuits      confronting electronics today is the sag        circuits being generally more susceptibl are used to switch."ne voltages via relays. which ~icaily occurs during turn on and          Surprising to many, the pnncipie threat Analog sensors are input devices:o digital      the spikes which typically occur during turn    not the TV or FM stauon down the roai controls.                                      off of heavy inductive loads. ~<..e sags        but rather it is the hand held L~snut:~
Increasingly. there is a need for a        simply starve the electronics. The high        carried around by facilities personnel. A or.
:ooperauve effort between the designers.        frequency ttansients barrel right through        watt radio will result in an electnc ne!d  ~
manufacturers and instailers to come up        the supposedly Stered power supply to          (Ne volts/meter at a one meter distance with a rock-solid system. A common              attack the electronics inside.                  enough to upset many electromcs systems complaint is that the mstallers or mainte-          Digital circuits are most vuhierable to        IEC 801.3 speciGes immunity to elec ".
narce people won't follow the instaUation      spikes which cause data ettors or worse.        Gelds of one to ten volts per mete requirements. This may be true, but it          Analog circuits are most vukierable to          depending on the equipment. with tive must change. smce there are problems            continuous RF riding on top of the power.        volts per meter being Se level for typic which cannot be solved at the board level.          FIPS PUB 94 provides guidelines on          equipment. As can be seen from the abov It is also true that manufacturers often        eiectrical power for commercial computers.      approximation, three volts per meter is nc specify installation .equirements which are    This is good infortnation, but beware that      an excessive requirement, and even:e not practical to impleinent, and there are      factory power is much noisier than commer-      volts per meter is fairly modest.
documented cases where the prescribed          cial power.                                          Electrostatic Discharges. EiecLc installauon procedures wil! cause rather            The guidehces of IEC 801.4 speci5es an      static discharge is an intense short durauoi titan cure a probietts.                        electrically fast uansient (EFT) that simu-      pulse, having a riseame of about one The!adt of umiken guidelines has ham-      lates arang and other high speed noise.          nanosecond. This is equivalent:o a burs.
pered EMC prtiless in the industriat            Ebs are quite short ranged  they                of 300 MHs interference. Static buildup.
arena. Fortunately, the European Commu-        diminish rapidly with distance due to induc.      of 15 kV are not uncommon.
nity is working to adopt the IEC 801.x          tance in the line. But at short range, they          Dry climates, including northern climate'.
specilications. and domestic companies          are devastatmg.
would be wise to adopt them, even if there            Unfortunately, attention is placed on the is no intention to export.                      front end of the electronics, the power          Wham Kimmel is a pn'ncipal with Kimme.
supply. With industrial controls, the prob-      Gerome  Associates. Ltd. The firm special.
The Basic Threats                              lem is the controlled elements. If the          i@ca in preventing and solving electromag.
The three basic threats to industrial      electronics is controlling line power, the      netic interference and compaabQity (E.Mh electronics are power disturbances, radio      disturbances sneak in the back end where          EMC) problems. Mr. Kimmei can frequency interference, and ESD.                little or no protection exists.                  reached at 3544 N Pascal, St. PauL .~i~
Power Disturbances. Power distur-              System ground, while not being specifl-      55108,  or telephone 612.330-3728.
EMC Test        4  Design
 
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i suitcl.e I                                                          piouer F:g.'re '.. Amp'.'Ger detnodulanon.                                        Figu:e 2. Transient!eedback path.
:n  ~".nter. offer opportumty !or ESD.          en cour ters a noriinearity such as a semicon-      to heavy equipment. wtuch.s;itc. -.
Industnai environments. with the:r moving      ductor device. All such devices give rise to          hy heavy starting .'oads and inducnve .
eq ipment. are loaded with potenual ESD        a DC level shift when confronted with RF.            a<<wn of TyptcaUY the e!ectronic con:r sources: rubber rogers. belts, and produc-      ln a radio receiver they are called detec-          switch Une power using relays or;;.-.
uon ou'.put such as plasnc and paper roUs.      tors. Noniinearities are minimized in linear        This exposes the back end of the cont;=
all add up!o a real ESD th:eat. and t."is        devices, but:here is always enough to cause          to substantial line transients. which coi-r."meat is more likely to occur even m          problems. The upshot is that the ampli6er            back to the circuit power and ground
        ;elanvely moist environments. Look:o IEC        demodulates the RF. generates an errone-            disrupt the digital circuitry as shown 801.2 .'or ESD standards.                        ous signal. and passes this error on. This          Figure 2.
effec'. is shown in Figure 1. Output hnes are            It is mandatory that the transient:
Elec! ronics Design                              similarly affected, with capacitive couphng          rents be diverted or blocked. since Electronics:s generally the ultimate        back to the input.                                            system cannot withstand t.".e .-.~g'igital victim of:nterference. The hter.'erence              The soluuon is to prevent the RF from            tudes likely to occur with an inducuve k:i Gnds its way through various paths:o the        getting to the amplifier. either by shielding        unless special steps are taken.
electronics equipment itself. Let's concen-      or filtering. The most common path to the                Self jamniing can be Unuted by contrcli trate on w'rat can nappen to your electronics    amplifier is via an external signal ine from          when you switch !he Une. using ze from !he back door. that is. by direct          the sensor. but if the ekctronics is not            crossing devices. Of partic~ importan radiation into the electronics and by con-        shielded. direct radiation to the circuit board      is the mrn off. since dtat is when ducted:nterference through:he signal and          may also present a problem.                          inductive kick occurs.
cont:oi lines.                                        Assuming filtering is the sekcted method.            lf a6 power switching used zero crossu Sensors. Low level sensors. such as        use a high ~frequency Glter, designed to              devices. the transient levels in the facto ther...ocouples. pressure sensors. etc.. are    bkick signals up to 1 GHz or even more.              wouki be dramaticaily reduced. Unfor.
characterized by very low bandwidtbs and        Use femtes and high frequency capacitors,            nately, that goal is well off in the futu:
      !ow signal levels. A major Meat to these        Do not rely on your low frequency Glter to            Until then, expect that high voltage pow sensors is radio frequency interference.        take out RF.                                          transients wlloccur, and they must be de either from nearby hand held transmitters            At the op amp. you shouM also decouple          wldl.
or more distance land mobile or Gxed              your plus and minus power to ground at tbe                Optical couplers and relays do not provi transmitters.                                    chip. If your ground is carzying RF, you can        sufficient isolation by themselves. Tht But:hese are high l'requency, much          anticipate the same probkm mentioned                high capacitance provides an excegent hii above the bandpass of your amph6er. right?      above, since it will comtpt the reference            frequency path, and if they are stacked t Wrong! Low frequency amplifiers are              level.                                                in an array, tbe capacitance wi6 add up plagued by two,ybeaomena: out of band                Data Lines. Digital data lines wiU be            pass surprisingly low frequencies. The:
response and <<stso rectification. These          upset by the RF problem as in anakig, but            capocitances an't be elim'mated, but yc combine to provide false information on          tbe levels necessary to upset are higher.            can design yow control circuits to minimiz levels to the system.                            Instead. digital data lines are tnucb more            couphng paths and to maximize low impe<
All amplifiers have a normal bandpass,      susceptible to transient ghtches. All signal          ance alternate paths.
typi6ed by a 20 dB/decade roUof or more          lines should be 6ltered to pass only the                  Transient suppressors should be installe at the high end. But resonances due to stray      frequencies necessary for operation. If the          at tbe kiad, which is the source of the spih inductance and capacitance will give rise to    threat lies in the bandpass of tbe signal,            but they can be installed at the controUt amplifier response Gve orders of magnitude      then shielding or optical links will be              as weal.
or more above the nominal bandpass of the        needed.                                                    An interestmg effect occurs when con amplifier. This means an audio amplifier              Switched Power Lines. This refers                bining zero crossing SCR regulators wu will respond to signals in the hundreds of      specifically to the power being contro9ed            low level Mnsors which use line frequerc MHz.                                            by the controller device. Industrial control-        noise canceHng techniques. Very seftsitiv The second aspect occurs when RF            lers are commonly tasked to control power            sensors sometimes are sampled. for t JQIL"August a~!
 
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      'f80                                                                    , burro u High Current                    Pouer VAC DC                    I PS              Electroni>>:s Fir're 3. Common industnai    powe. supply.                              Figure 4. awful:rple ground paths.
enure    power    yc!e  to cancei  the ine          l(ore or'.eh '.he problem is conducted.          eliminate RF of g.ound noise...at freq'ncy conipohent. If t..e  samp!e occurs      eirher 'aa power or graurd. The problem            work, but:hese problems can be rc.
co.","u;.ently wi:h ire power sw'.tching on      occurs due:o power and g.ound distur-                with an isolat:on rant(armer:o =".-..-
or oif.:he average :o rhe sensor will be        bances caused by the equipment. It is an all        neutral to ground noise and ~~rh "~II po;
    .pse'.. and an e.-.or ~4 "e recorded.            too common pracdce to draw controiier                linc Glters. So you may wan:;o try power f;om the same source as feeds the              inexpensive approach nrst.
System Design and Installation                  power eqtupmcnt. T."is power may provide                Data I.inks. Data links are su.~ng Once >e elect:onics is designed. it            :he recessary energy to drive the equip-            over the er'.tire!acirty. exposing ther.:
becomes a p.oblem of!he system integratar        ment. but it is not suitable to power the            two principle e((ects. ground raise are and installer:o ersure that thc electranics      electroiucs lFigurc 3).                              pickup. Ground nois>>; will cause data er.-
is cravided wuh the environment far which            Hopefully, all indusuial equipment wiU            unless the electronics has been designe" it was des;gned. Most of thc umc. this            have electronics powered from a separate            accornmodatc potential differences of ->>
work is performed by power experts and            low power 120 volt circuit. It solves several        eral volts or more. This is accampbs; clectricians. and they are not always aware      problems. First. it separates the electron-          with dif(crential drivers and receivers:f =.
of:he intcrfererce probkm. Often, on site.        ics power from the probably very noisy                must be direct coupled. Optical 'hnks-rhe power quality is blamed for thc equip.      indusu@ grade power, prevendng the                    eventually take over these links.
rrent anomalies. But the problem can often        switching transients and startup sags from              The other aspect is RF pickup. Inexpe be avoided by following a (ew basic prina-        genug to the electronics. Second, if it is          sive shielded cable is suitable ples.                                            necessary to condition the electronics po~er                    Ground borh ends! Do not app (ar:.'urpose.
The industrial conuol device is either        from an extet".A problem, it is tar cheaper          single point ground techniques to RF. i!
integrated into a system at!he factory or        to condiuon the watts necdcd (or electronics        Iaw frequency ground loop problem:s instaL'ed separately on site. Controllers        power than it is to condition thc kilowans          threat. then onc end can be capaciuve handle a varicty of devices such as motor        required by the system.
speed controls. positioning devices. weld-            If power cannot be separated. then it is ers, etc. fnterferencc presented to the          necessary to provide a bu!letproaf power            Summary electronics can be signiGcandy reduced by        supply. preferably incbrding an isolation                Industrial electronics are subjected rc appropriate measures outside of the elec-        transformer, to separate the entire power            harsh environment. Good design and inst.
uonics box.                                      supply from the electrical equipment.                !ation techniques will minimiae problems There is no way to accurately assess die          Ground Noise. Ground noise, inevita-            thc Geld. Adhcrencc to the Europe; rhreat without test data. But rcgardlcss of      ble in industrial environments. must be              standards, IEC 801.x is a good start, ev>>
the br(oration avai!ab!c. much can be            diverted from the electronics modu!c.                if you are only markeung in thc USA.
accomplished by correct instagation, and it      Multiple grounds in a system wiG often doesn't cost much if done at the start.          result in ground curt ents circu!sting through        Bibliography RetroGts become cosdy. especially if ac-          the cquiprnent. and ground noise circuhting          FIPS PUB 94, Guideline on Elec'ac:
companied with factory down time.                  through thc electronics path will cause              Power for ADP Installauons. Scptcmber Let's consider dsc same prob!cms from        rnalfuncuon. Figure 4 shows some typical              1983, a system standpat. Your goal is to limit          ground loop situations.                              IEC 801-2. Electromagnetic compatibilit.
the interference wfskh must be handled by            A common approach is to demand a super            (or industrial. process measurement an<
the electronics.                                  ~arth ground. This is good, but it is not a          control equipmcnt, Elcctrostauc dischargr Direct radiation to the electronics is not    cure all. and often a super ground cannot            requirements, 1984.
often a problem in an industrial environ-          be achieved, no matter how you uy. How                (EC 801-3. Electromagnetic compatibi!it!
ment, but it does occur, and most often with      do you get a super ground from the third              (ar industrial. process measurement anI a plasuc enclosure.        The NEiMA type        4oor? The real need is to gct'a stable ground        control equipment, Radiated electromag enclosures provide enough shielding for            reference to all interconnected equipments.          cetic Geld requirements, 1984.
most mdusuial needs. If you don't want to          If this equipment is closely located, then a          IEC 8014, Electromagnetic compatrbilit:
use a metal enclosure, be sure !o get              very low impedance interconnect is feasi-            (or industrial-process measuremcnt ar.:
elecuonics which will withstand the RF            ble.                                                control cquipmcnt. Electrical fast:ransreht which will occur.                                      Power conditioners are o(ten tasked to          burst requirements. 1984.
EMC Test      8c De .<n
 
e industrial Fquipment Equipment Ground Bondlng-Designing for Performance and Life A Discussion of Ground Connection Fundamentals to Control EMl By D.B.L. Durham Dytecna Ltd, UK The problem of achieving satisfactory earth      eqtdpment to a stable ground point. achiev. inductance. At very high ~equencies:r bonds or ground connecuons has plagued          ing adequate levels of cabk shiekhng and for    stray capacitance across the strap EMC engineers for many years, not only          many other reasons. Many designers un-          donunate. This means that the volt "-:
because the bonds are often vital for the      derstand the requirement for short. fat bond    across a bond is generaily a funcuon achievement of satisfactory equipment pei-      leads to minimiac ground inductance, but        inductance and frequency. Based on Ohr.".
formance but because they affect the long        few appreciate that a critical aspect is the    Law this volt drop is shown in Equador. ~
term performance of equipment after it has      connection resistance with which the bond        For transients the voltage drop is giver..
been introduced into service.                    strap is attached to the equipment ground      Equation 5.
Recommendations on bonding have ex-          point. Thc basic requirement of any bond isted in the form of military speciBcations,                                                      Z      Rt + cutLS is that it should have as low an impedance such as Mil Std 1310. Mil 188-124A and          as possible (uille55 it is a dchbcratc induc-Mil-B.5081 (ASG) for some years and these        tive bond to limit ground currents). Tbe        V    IZ ~ jauU have generally proved satisfactory for most      impedance is a combination of the resistive new builds. However. these speci6cations        and the inductive components. Thc resis-                  d1 (5
have certain limitations in that they gener-    tive element is a funcnon of thc bond strap                dt ally do not spectfy consistently low levels      resistivity, cross sectional area and length. where Z ~ strap impedance. cu ~ tacoma of bond impedance. nor a suitable test          see Equation 1. whiht the inductive compo-      frequency, V ~ voltage, and 1 ~ current.
method. The introduction of ncw EMC              nent is a more complex function of thc bond        From this. the higher thc inductance th speciGcations in Europe with the EEC            strap characteristics as shown in Equation 2. more isolated the circuit or box become Directive on EMC and the requirements for                                                        from ground. Ths can have sigru6can R~-    qf                                  0 j'f iong tenn stability in EMC characteristics                                                      effects oa equipment. inchding enhance has directed the UK nuTitary to review                    A                                      ment of noise injecbon onto arcuits, reduc=
cidsutlg spcciEcaQons and Introduce a ncw Defence Standard to tighten up perfonn-
            ~
ance requirements for nurttary equipment.
Dcf Stan        (Part 1)/1 has been intro-L    iZ, 2ic L
                                                              ~
ln b~c
                                                                          + 05+  02235  j b+ c" 2f J non of Ster performance, and loss oi coaunlmication range. From a TEMPEST standpoint it may result in more radiation from emanent. lt would seem from this (2) ducal to address thia area as far as mob9e                                                        that the cntcria tor any bond is the and transpottablc canmunications installa-      where R        resistance, g ~ resistivity, f>  inchlctancc and hence thc choice of short fat tions are conccnteia. but the requirements                    ~
length. A area, p, pcrmeabiEty of free shoukl have implications in industrial apph-    space, L ~ inductance. p ~ feLttivc            David Dugan served for 21 yean itt the cations and over the wlxHe ekctronics            permcabiTity, b strap width, and c stttp        Brrtiab Anny, where hc gained his Chgree market if long term product performance is        thickness.                                      ia dectricaf cnginceting. After service in a to be guaranteed.                                    The frequency at which the inductive        variety of appointments hc retired to join ekment dominates the impedance expres-          the Recalls'ES company as the Techmca/
Bond Degradation                                  sion when calcu!ating thc total inductance      Mtnsgcr rcspottsiblc /or the cfes/gn and Earth or ground bonds are generaHy          is, from Equation 3, typically 1 kHs. lt wgl    devclopnsettt of commctttication systems.
considered essenual not only for safety          be seen therefore that to al intents and        fn 198$ he jainef Dytecna as the iManager reasons. but as a mean of diverting EM          "
purposes thc bond except at DC and power        of the &ginecnttg Division. and now ts currents, "locking" circuit boards and            frequencies, may be assumed to be an            currcntfy Tchtaica/ Marftcting Manage..
38                                                                                                                            JulytAugust !991
 
5 P
 
sc';o  rc(c gq(r      rri.
                                    ~~~cwc  "-av    ~
                                    ~l-  l 'sis~fN f          $ Qsk                                                gRrrf NT 'N,ff 'Srn ryort:4i  csi r:i.rrenl
                                                                                                                                                ',:!0 iQ A. os JVA5Hf5 rrllt fR scarc 5 err VOUAGE    &ifASI 'REhlENT Figure!. Bond resisurce.                                                      Figure 2. Four wire bridge method.
bond straps. However. an anaiys's of:he              progressive degradation nt bonds, whilst                  current thc layers heat up and are vapo-bondinductancf shows Jiat I'or a bond strap          the latter can reduce the ef'ciency of the                rised. After the current is removed t.".e Sm of 100 mm!or g, 15 mm ~~de and 2 mm Ihck            bond f;om the moment it is installed. It is              can return. Thus high currert techmques the impedance at 1 MHa will be 3.8 Ohms.            particuiariy important in communications                  are not recommended ror:esang EMI It sounds extremely sin:pie. but work                systems, where 6lters are insuiied and                    bonds. The new Defence Standard in the performed in '.he USA'nd I:K shows that              shielded cable ternunations are made Jiat                UK speci6es a maximum probe voitage oi if an etrot is made 'in the way the strap is        the bords are of ',ow resistance and reuin                100 mictovolts. This reprcsenu typically a ternunated then a progressive increase in            their perfonnance.                                        probe current ol 50 milliamps under shor
:he resisunce of the bond strap to box                                                                        citciit (< 1 mQ) condiuons. This -:s juncnon can occur as the equipment ages.            Bond Performance and                                      insuf6cient to destroy surface 5lms. The Eventuaily the resisunce will begin to              Mtaalaremcnt                                              chssic method for measuring low resisunce exceed hundreds of ohms and may eventu-                  Experience has shown over a number of                has been to use a four:erminal bndge as ally go open c cuit. This can negate thc            years that for long tenn consistent bond                  shown in Figure 2. In this case'the current effect of the bond strap completely as part          performance a low value of resistance must                is driven between two points and Ae of the E!rII protecdon.
tVhat happens with bonds to cause this change! Essentially a ground connecuon is In Def Stan    ~
be achieved. This is typically 1-5 milhohms.
(Part 1)/1 the vahie has been set at a maximum ol 2 miUiohms. This VOltage aCtOSS the Sample iS meaSured witN a high resisunce probe. This removes Jie cfccts ot thc ptobe contact resistance and a series of irrpedances      from thc strap          level is measured through the individual                  lead resistance. This is generally consid-through to the grourd material, as shown            bonds. Thc logic behind this level is                      ered to be a laboratory method as the use in Figure 1. Each point of contact contrib-          twoloid. Firstly. experienc has shown that                of four contacts can be awkward. If the lead utes to the total bond per'.onnancc;. As a          with communicaions equipment in particu-                  resistance can be removed by a calibrauon result. a change in any contact condition can        lar this value ol bond resisunce is required              teclniquc then thc four terminals may be result in a change in the total bond                if consistent performance is to be achieved              replaced with a two terminal system.
resistance. As is weil appreciated, the"            in terms of reception ef6ciency and trans-                    h further possible re6ncment to the contact resistance between two metal sur-            mission characteristic. This is particularty              tecluique is to use a frequency that is not faces is a hnction of the pressure. The              so for TEMPEST protected equipments.                      DC or 50/60/iOOHx. In this case 10.4 Ha pressure exerted by the tip of a drawing pin        Tbe second point is that if the bond has a                haa been chosen. If an active 6lter is used is vastly greater than that from the thumb          higher resistance then there is a signi8cant              to Ster out a9 other electrica noise, then pressing by itself. Thus the contact from a          likelihood that progressive degradation will              it is posgblc to use the bond resistance sharp poult gives a tsoch higher prcssure            occur and the bond resistance wig increase                meter on powered up systems. It is worth t.'un a Oat point and 4gtiforc lower contact        in value. There will then be a progressive                noting that at this frequency the impedance resisuncc. Measutetata have shown that              loss in perfonnance.                                        ia stol htgcly represented by resistance sharp points enable Contact rcsisuncc of a                The main problem with measuring bond                  rather than inductance. The two termmal few nicroohm to be achieved whilst similar          resistances is that it should bc measured                  method is shown in Figure 3.
pressures on Oat surfaces result in mil-            using a low voltage/curtent tcchtilquc,                        The introduction of new EMC/EMI liohms of conuct resistance. It might be            Moat techniques to date for assessing                      spcci6cations in Europe has made it more felt that there is little or no difference                        driving a large current through the safety'nvolves important that once made the bonds have between these values, but in reality there          bond. This checks the bond's abiRty to                      coils latent long 'tcrlil performance. Ths is. An essennai aspect of a good bond is            carry current but does not necessarily check                means measurin on periodic inspecnon ard that it should remain so after the equipment        its EMI protection perfonnance. The rea-                    aRct maintenance. It is an essential aspect has entered usc. High pressures also have            son is that many bonds may when in normal                  of insutmg consistent perfonnance. It has the effect ol squeesing out corrosive materi-        use have a high resistance due to oxide and                been shown that within months apparen Jy als and insulating 6lms. The former causes          greasy 6lms. but when subjected to a high                  good bonds can deteriorate to .-igh resis.
EMC Test & Design
 
tance. Ther.io.e t.'i vces ii      '-.  ~
AAeqT                                              suo)ect to testing and .xa.-..;.-.a:.cn-as a ma:ntenance tas~.
                                ~      ic'oK ue45uI>eNr                                      L K ~military Experience There have oeen '.wo ~ lcr -.::
caused by poor bonus expenence eiieo otsis ascg          0                        degradauon .n ericrmance ~ready-uoned in:tus a.-.icle. The:oss i;cir, cation range. poor EMl pe.",'ormance other eifects aL'onrnbu'.e to a cons:dert reduction m equi".-..ent Nc:ency ann a.
ability. The secord ei;ect wnich is .
difficult to denufy:s:hat ai No Fault F.
(NFF) problems. An analysis of reN'."
failures from military reiiaLiity data .
shown that NFF inc:dents can ae extre..
high, particulariy:n hunud;timates.
FIXED RKSlSTANCE LEAOS                                      has been partially confirtned by reports .':
the Gulf Sar when aH forces repor-.e.
increase in availability of equipmen: .;.
clunate. Many fau!ts are due to "    'rier electrica contacts in connectors. bu: a lar number have been idenufied as excess:
Figure 3. Two termmal bridge method.                                                      EMI induced through poor ground onnc This may be caused by either a loose groi strap or connector terminauon to:he ':c A significant improvement In equipme 4            4                              availability and perfonnance is expec:e y                                    when more recent statisucs are analysed.
The introduction:nto the Bnush Ar.-.
service of Ae Dyteaa Bond Resistanc I                c<~~  4c    c>~  ~~c Test Set DT l09 has enabled the L":
mihtary to measure bond resistances installed equipment and reduce;he curances of NFF errors. The UK mi:ar measurement procedure uses a two:er-...:
nal bridge method and an accurate miiliohm calibration star. dard. This meas urement procedure and equipment is als in use by other NATO nations and e!se where by iniTitary and naval forces wro hav recognized the same problem.
Cottclueiotta The problems with ground bonds have become significant with the development o:
            ~ ( olnpi4lllA      Q~+  c~ ~            (4 eeoc    4  ((i+  yo    ~befit%
sensitive and secure communications equi"-
ment. This coupled with an increasing reed CUSTOMQAG Ti                4.++++"          9t  ~o'4+      a  ~~>      t iQN        to achieve higher and higher leveh of KMf CQMNC Rf AC.                0 odgot          tc~ 'e+  b~+.=nuators,            protectiwt has lead to an increased emphasis beng placed on the effectiveness of all types Coaxial Term.        %/@
                                        ~4. ~b,~
                                                  <  y<c    <4~ connectors, of systettt grounds. These. further com-bined with a requirement to ensure the long Cata        ~pc+ q4      .attest                            life of systems once in service. have resulted in the assessment that bonds and lE                                                    terminations are one of the primary causes of EM faBures in systems. The require-11?0-1? bnCOln Avenue. FOlbrOOk.;4Y 11741                            ment to test these is clear. however the (S16) ~85.)4tX1 FAX i16.~BR >l14                              means to do so have not always been available to engineers.
INFO/CARO 29 40                                                                                                                        July.Aug.st '.9o'.
 
Panel SessIon PES Summer Meeting, July lQ, 1988 Long Beach, CaHfornia John G. Kappenman, Chairman Power System Susceptibility To                                  Induced. currents in the system, 2) the interconnected sys-tems tend to be more stressed by large region-to.region Geomagnetic Disturbances:                                        transfers. combined with GIC which will simultaneously turn every transformer in the bulk system into a large reactive Present And Future Concerns                                      power consumer and harmonic current generator and 3) in general, large FHV transformers, static var compensstors and relay systems are more susceptible to adverse influence and microperation due to QIC.
John C. Kappenman, Minnesota Power The effects of Solar. Geomagnetic Olaturbancea have been        TRhNSFORMER OPERhTION observed for decades. on power systems. However, the pro-found impact of the March 13, 1989 geomagnetic distur-          The primary concern with Geomagnetlcally-Induced Cur-bance has created a much greater level of concern about the    rents la the effect that they have upon the operation of large phenomena in the power industry.                                power transformers. The three major effects produced by GIC in transformers Ia 1) the Increased var consumption ot the Several man.made systems have suffered d)eruptions to their      effected transformer, 2l the increased even and odd harmon-normal operation d)aa to the occurrence of geomagnetic phe-      Ica generated by the half. cycle saturation, and 3) the possi-nomena. Moat of the man~e systems, such aa commu-                bilities of equipment damaging stray f)ux heating. As is weil nications, have brett made less susceptible to the phenom-        documented, the presence of even a small amount of GIC ena through technological evolution (microwave and fiber-        I20 empa or less) wN cause a large power transformer to optlc have replaced metall)c wire systems). However, the          half-cycle saturate. The haif~c)e saturation distorted excit-bulk transmission system, If anything, is more susceptibl ~      ing current ls rich ln even and odd harmonica which become today than ever before to geomagnetic disturbance events.        introduced to the power system. The distortion of the excit-And lf the present trends continue, it la likely the bulk trans-  ing current also determ)nes the real and reactive power re-mission network will become more susceptible In the future.      quirernents of the transformer. The saturation of the core Some of the most concerning trends are: 1) Th>> transmission      steel, under haif~c) ~ saturation, can cause stray flux to en-systems of today span greater distances of earth-surface-        ter structural tank members or currant wlndlngs which has potential which result In the flow of larger geomagneticaily-    the potential to produce severe transformer heat)no.
IEEE Power Ealineeciag Review, October 1989                                                                                  15
 
t I
 
tr:rscs'rr ei    '-  ry es. -e 'io:est 'esul!S trct  ~
                                                                                    ~  u ~    >>        ~ ne ear!:i d, <<3g. 4!'
geonag,"et.'c storms when!hey are -'                        '- 4, 4 C      4    dra
                                                                                                                                                  ~
de~~"      ~
:ste '.na; Stogie CnaSe sr 5.'"r-..erS;ai'CVCle Saturate muCn mere easilv ano!0 4 -"cn greater cegree;han ccrricarable
    .;nree onase units.."ese:.ansformers          produce higher mag.        SUNSPOT CYCLES hND GEOMAGNETIC nnuces of harn onics and "or sume!arger amounts of rese-                DISTLRBhNCE CYCLES
      !rve power when comPareO with three phase deslgnS.                    On the average, solar              activity. as measured by t."e nur oer ".
monthly sunspots. follows an 11 year cvcl'e. he "esen!
ItELhy      HAND  PROTECTIVE SYSTEMS                                  sunsoot cycle 22 had its minimum tn Seoten.oer 1986. a."c is exoected to oeak in 1990-1991. Geomagnetic 'ela o 5                                    ~
      >here are    three ba5ic faitire modes of relay and protective        tvrbance cycles do not have the same shaoe as:ne sunscot Svs!ems:nat can oe attr:buteo to ggeomaghetic distur-                  number cycles. even thOugh they are cyclical. F Sure snows                      1 bances:                                                                the nature of the sunspot numbers and geomagnetic 3C!i"".v r
          ~  . alse Operation of:."e protection system. such as hav-ing OCCurreO rOr SVC. CabaCitar and line relay Opera-          SurtsIre4                            i 431 ~ 1444                              4uit'ocr or tions where:t e!tow of harmonic currents are misin-                                                                                            C(rtworts
:erpreter2 OV the reiaV aS a rault Or OVerlOad COnditicn.                    Cycle i7 Cycle la Cycle ia Cyote 20 Cyci ~ 21 Cctrs  rrrr apr25 This is the most common failure mode.                                                                i            I l        irumoer el                                                r i Olslureetd OdyVyear              Suitspoi Humber                  ~
                                                                                                                                                              )40
        ~  Failure to Operate when an operation is desirable, this has shown to be a problem for transformer differential              150 t
                                                                                                                                                          ;    120 protection schemes and for situations in which;he                          I
                                                                                                                                                              ~
00 output of the current transformer is distorted.                                          I                                                  I l00  j            ii                                        ~        ~  d0
        ~  Slower than Desired Operation. the presence of GlC                                      Ii                                                  I can easily build up high levels of offset or remanent                                                                                        i  de i
ttux in a current transformer. The high GIC induced off-              50  j,  I r
I        )
I ui I
i 40 set can significantly reduce the CT time.to.saturation                                                            I                          I
                                                                                                                              \
for offset fault currents.                                                                                                                  ~  20 1
Most of the relay and protective system misoperations that                                                                              ~      ~  . ~  0
                                                                                    !400 35      ee    cS  50  55    40    45  70 75  40  45    40 are attributed to GIC are directly caused by some malfunc-tion oue to the harsh harmonic environment resulting from              Figure 1. Vaitstfons of the Yearty-Averaeed Sunspot Number enid large power transformer half-cycle saturation. Current trans-          Qetsmaenettealty Olsturbed Oays from '1 932-1SBB.
former response errors are more difficult to directly associate with the GIC event. For exampfe in the case ot CT remen-encc. the CT response error may not occur until several days          cycles from 1932 to 1988 i2, 3l. Note that the geomagnetic after the GlC event that produced the remanence. Therefore.            dleturbanCe CyClee Can haVe a dOuble peak, One Of WhiCh Can these types of faitures are more difficult to substantiate.            lag the sunspot cycle peak. While geomagnetic activity in the present cycle is expected to maximize in approximately 1993-1994, severe geomagnetic storms can occur at any CONCLUSIONS                                                            time during the cycle; the K-9 storm of March 13, 1989 was As evident by the March 13th blackout in the Hydro Quebec              a striking example.
system and transformer heating failures in the eastern US, the power industry is facing an immediate and serious chal-            EhRTHQURFhCE.POTENTIhL hND lenge. The power industry is more susceptible than ever to the influence of geomagnetic disturbances. And the industry            GEOMhGNETIChLLY.INDUCEDWURREVTS will continue to become more susceptible to this phenome-              The auroral electrojete produce transient fluctuations in the non untess concened efforts are made to develop mitigation              eanh'5 magnettc field during magnetic storms. The earth is techniques.                                                            a conducting sphere and portions of ft experience this time-varying magnetic field, resulting in an induced earth-surface-potentlal lfSP) that can have vetuee of 1.2 to 8 volta/km t2 Geomagnetic Disturbance Causes                                          to 10 volte/mile) during severe geomagnetfc storms in re-gions of low earth conductivity l4),
And Power System EEects flectric power systems become exposed to the 8 SP through the grounded neutrals of wye-connected transformers at the Vernon D. Albettsw2                                                    opposite ends of long transmission lines, ae shown in Figure University of iiIJnaaota                                                2. The fSP acta ae an tdeal voltage source impressed be.
tween the grounded neutrate end has a frequency of one to a few mittfhene. The gsomagnetlcally-fnduced currents lGIC}
SOLhR ORIGINS OP GEOMhGNETIC STORMS are then determined by dividing the ESP by the equivalent dc The solar wind ie s rsrffied plasma of protons and electrons            resistance of the paralleled transformer windings and line emitted from the sun. The solar wind fs affected by solar              conductors. The GIC ls s ques%tract current, and values in flares, coronal holes, and disappearing filaments, and the so-          excsee of 100 emperse have been rrNaeured in transformer lar wind paniclee interact with the eenh'e magnetic field to            neutrals, produce auroral currents, or auroral etectrojste, that foltow generally circular paths around the geomagnetic pate! at al-titudee of 100 kilometers or more l1). The aurora borealis ie            POWER SYSTEM EFFECTS OF GIC visual evidence of the auroral electrojets in the northern              The psr.phses GlC in power transformer windings can be l6                                                                                                IEEE Power Engineering Review. October 1989
 
1 ~
44 Ina ia.sat~tat.ah
                                                                                            ~                    n rich I:.tars gr~ers ause    clay misoperat on tet REF EHENCES
                      ~ 44                                            I
                                                                      ~ ~
: 1. Akasatu. S. I"The OyhtmiC Aurcra, 'ciehut C Ame":~
Al              =.sr~ ti.RFACS                    9          Mageziht. May 1989. pp. 90 97 T    SARvii-SuRFACS      <T5hti41.  ~
          ~ 2. Induced 5aich. Surtact-Poitntial ISSP) Producing Qtamtg.
t'igui
: 2. Jactlyh. J. A.. "Reel-Time Ptedicuch ot Gfcbal Goon agr ti Activny, Saltr Wind Magnetosphere Cauphi'g, "p.
141. Tarrt Sciehuflc Publishing Company. oxvo. '986.
htticaliy Induced Cunehis IQICI in Power Sytttmt.                          3  Thompsah. R. J., "The Amplitude at Saiar C.cie 22, Riidia ehd Space Sewiciis TtchhiCal Report TR 87 03, ctc bti 1987.
4  V. O. Albertgan ehd J. A. Vth Batten, "Utcuic phd hlaghe.;i many times larger than:he RMS ac magnetizing current, re-                      Fields at tht Stnh's Surface dut io Aurartl Cunenls." i55i sulting in a dc bias af transformer core flux, as in Figure 3.                TcahaaCIiohs ah Power Apparatus and Systems. Val. PAS 39 hia. 2. April 1970. pp. 578-584.
: 5. J. Q. Kappehmtn, V. O. Albtrtaon. 9. Mohan. "Curser Trahatarmtr ahd Relay PtrtolmtnCt ih the Presence ot Gtc magnetically Induced Currents." ISEE Triiheactians ah Paw e~
Apparatus ahd Systems, Vai. PAS.100. No. 3, pp. 1078-1088. March 1981.
I  I lo,pl              I~            The Hydro-Quebec System Blackout Of March 31, l989 io.ai
                                      <<ICI<<r~                              Daniel Saulier, Hydro-Quebec On March 13. 1989. an exceptionally intense magnetic storm caused seven Static Var Carnpensators ISYC) on the 735-kY Rgurt 3. OC Btt! af Trtntfarmtr Cart      Rulc Out to QIC.          network to trip or shut down. These compensetors are es-sential for voltage control and system stability. With their loss. voltage dropped and frequency increased. This ted to systartt instability and the tripping of all the La Grande trans-The half.cycle saturation of transformers on e power system              mission lines thereby depriving the HQ system of 9500 MW is the source of nearly all operating and equipment problems            of generation. Tho remaining power system callapsed within caused by GIC's during magnetic storms. The direct conse-                seconds of tho loss of the La Grande network. The system quences af the half-cycle transformer saturation ere:                    blackout affected ~ it but a few substations isolated anto lo-
      ~    The transformer becomes a rich source of even and              cal gene~sting stations.
odd harmonics                                                  Pawer was gradually restored over a nine hours period. Oe-
      ~  A great increase in inducttve vers drawn by the trans-        leya in restoring power wore encounterea because of dam-former                                                        aged equipment on tho La Grande n>>twark and problems with
      ~    Possible drastic stray leakage fiux effects in the trans-      caid load pickup.
former with resulting excessive localized heating.
There are a number of effects duo ta tho generation of high              SYSTEM CONDITION PRIOR TO THE EVENTS levels of harmonics by syatim power transformers. includ-                Tatal system goneratfon prior to the events was 21500 MW.
ing,                                                                    mast of it coming from remote power-generating stations at La Grande, Mantcouagon and Churchf8 Felts. Exports to Overloading ot capacitor banda
      ~  Possible rntsaperottan of relays                                neighboring Systems totalled 1848 MW of which 1352 MW were on OC interconnections. The 735-kV transmission net-
    ~    Sustained overvoltogos on lang. line energizattan wark was laded at 90% of tts stability limft.
Higher socondory arc currents during single. pole switching      .
    ~    Higher cfratffC Maker recovery voltage                          SEQUENCE OF EVENTS
    ~    Ovorlaadtno of harmonic fttfyrs of HVOC converter ter-          At 2:45 o,m. on March 13, a very intense magnetic storm minals, and dtotantan in tfio ac voltage wave shape            ted to the conaequortttal trt p or shut down of seven SVC's, that may result in loss ot dc power transmission.              Contafnlng tho impact of tho event through oporatar inter-The increased tnductfvo vora drawn by system transformers                yention was impassible att SVC'a having tripped at caaaod to during halfwycl~ soturat)an are sufficient to cause intoler-              function within o ano minute period.
abto system voltage depression, unusual swings in MW and                  A fow seconds l8-8 s.) after tho loss af tho last SVC, ~ II five MVAR flow on transmission linea. and problems with gener-                735.kV lines of the Lo Grande transmission netwark tripped ator var limits in some instances.                                        duo to an out of step condition. These Itne trips deprived the In addition to the halt-cyclo saturation ot power trans-                  system ot 9500 MW ot generation and subsequently ted to a formers, high levels of GIC can produce a dlstarted response              campteto system cat tapao.
17 IEEE Power Engiaeerintf Review, October f989
 
1
  \
 
:ecuon ance re~air ir 9 'cur SVC's snot sown ov caoac tor              DIsturoances On Poiyer Transformers
            ~oitage uncaiance prctec::o." >>aivsis ot vootage ano cur.
rent osc:itograms taxen at:ne Ct ioougamau site before tne i
SVC tnps snowed tne '.oitowing narmonic contents.
Hooert  J  Hingjce O
  ~                                                                              James B. Stewart
                                  .wC              ,hC Current ar l6 ky Harnaiiic          Vcliage                                            Power Techttoloip'es Inc.
Order          at .35  ky    TCA Bracche          TSC Brasche    This discussion addresses the effects of geomagnet:c cistii" oances on power transformers. The primarv effect:s cue tc 100'"o          '&#xc3;"                    I00~o      core saturation resulting!rom geomagneticaltv incucea c r      ~
9 of                  36 ~o    rents. GICs. Core saturation can imoose severe temoerature 1OO 24  ~
problems in windings. ieads, tank plate ana structurai mer.-
3'io          I  Oof
                                                                        }6 ~o    bars of transformers and place heavy var and harmonic oi.r    ~
a  ~          5  Oof 5%
I ifo I  ~                16 ifo dens on the power system and voltage support equiprriant.
3~o            3~o                    a ff    GIC's of 10 to 100 amperes are more:hen mere nuisances in tha operation of power transformers, the rnanr.er of !Iow Quasi DC currents generated by:he magnetic disturbance,                can result in saturation of the core and consequent changes saturating in tne SVC coupling transformers are thought to            in system var requirements. increases in harmonic curren.
be the cause for such a targe second harmonic component of              magnituctes. increased transformer stray ana eady tosses.
currant in the TSC branch.                                              and problems with system voltage control.
GENEAhL OBSEAVhTIONS ON THE SYSTEM                                      CIC EFFECTS VERSUS CORE hND WIIOoDINC BEHh VIOA                                                              COiVFIGURhTIONS The system blackout was caused by loss of all SVC on I.a                Principal concerns in this discussion are for EHV systems Grande Network. Seven SVC tripped or stopped functioning.              with grounded Y transformer banks providing conducting Prior to and during the event all the OC interconnections be-          paths for GIC and zero sequence currents. Cora and winding haved properly. No relay false trips or misoperation of special        configurations respond differently to zero sequence open.cir-protection systems were observed. Telecommunications                    cuit currents end to GICa. Note: aa used here. the term "open ware not affected. No equipment damage was directly attrib-              circuit"refers to tests performed with all delta connections utable to GIC but once the system split, some equipment waa              opened or "broken." For example, the three. phase three leg damaged due to load rejection overvoltagea.                              core form transformers aro less prone to GIC induced satu-ration than three-phase shall form transformers. But. both core form and shell form single phase transformers are sus.
RF'VIEDIhL hCTIONS ThKEVi                                                ceptibl ~ to GIC induced saturation.
Since the event. the following actions were implemented:                Winding and lead arrangemanta respond differently to GIC
            ~    SVC protection circuits have been readjusted on four induced core saturation aa well. For example, the current dis-SVC's so as to render their operation reliable during        tribution within pareil ~ I winding paths and within low voltage loads depends upon the leakage flux paths and mutual cou-magnetic storms similar work is being performed on pling. Loaaea within windinga and leads may change signifi-the four remaining SVC's, cantly under GIC induced saturation owing to the change in
            ~    Energy, Mines and Resource Canada now provides Hy-            magnetic field intensity. H, and the resultant changes in the dro.Quebec with updated forecasts on the probability          boundary conditions for the leakage field path.
of magnetic disturbances. Thaao forecasts are used by the System Control Center dispatcher to position the transmission system within secure limits.                      EDDY LOSSES IN STEEL MEMBERS
            ~  A.C. voltage asymmetry ia monitored at four koy lo-            The changes in the magnetic intensity. H, and the magnetic cations on the system (Bouchorvitto, Amaud, LG2,              boundary conditiona resulting from the GIC excttation bias Chhtgeaguay). Upon detection of o 3% voltage aaym-            can increase tho loaaoa in steel plate, the losses for fields rnetry at any ona location, the ayotom control center        parallel to the plane of the plato increase nearly aa the square dispatcher ia alarmed and will immediately ta'ko action      of H. Note also that the level of losses increase approxi ~
to position system tranafor levels within secure limits      mately aa the square root of the frequency ot H. owing to the if this haan't already been dane because of forecasted        effect of depth of penetration. Tho magnetic field along yoke magnetic activity.                                            clamps and leg plates in core form transformers and in Tee beams and tank plate In ahoN form transformers closely matches tho magnetic gradient ln tho core. Areas of the tank OPERhTING LIMNIDURING                                                    and core clamps are subjected to tho winding leakage field.
MhGNETIC DISTURShNCES                                                    If the coro saturates, the magnetic field impressed upon the (hND hLERT SITUhTIONS)                                                  steel members may rise ton to one hundred times normal duo to the saturation and the offocto of the leakage field. The The fallowing operating limits are now being appliedt                    loaaoo in the stool momboro will riao hundreds of times nor-mal, even under half-cycle saturation. On tho steel surfaces.
          ~    10% safety margin shall be applied on maximum trans-fer limits.                                                    eddy lose density moy rise ton to thirty watts par square inch,
        '                                                                    approaching the thermal flux density ot an ~ lactric range ele.
Maximum transfer limits shell not take into account tho        ment.
availability of static componaators deemed unreliable.
          ~    Adjust the loading on HVOC circuits to be within tho          Surface temperatures riao rapidly with this thermal flux and 40% to 90%, or loaa. of tho normal full load rating.          can result in degradation of insulation touching tne steel l8                                                                                          IEEE Power Eatpaeeriag Review. October l 989
 
r Ocl lr lent vendor Destgn Ocf tcfency          aafma1 UPS haS              Vendor no  battery              naINIa1 test            na  int enanc e CI I'CUI t      sect loA docs AOI QCAt I OA batteries.
Battefies have not been      Design Deficiency replaced in Design Deficiency        6 ycafs k.S relay Back up      charactertst-                    Breaker batteries      ICS PfCveAtS                    ffcIct ion AC          degraded or        transfer to                  per design input to            dead            inverter logic poucr                          output.
salty is naihtchahcc preferred Ground          Vol tagc              AC pouer to                        logic trips                    Breakers      ups loads fault occurs  on    traflicnt            logic nodule                          OA  poucr    2VSS UPStA,S,    CS-I,2  3    do hot auto loss of all phase of aain  oA    stat lofl        for UPStA.D,G      out pu'I            SISIPty      C,O,G trip    open; Ch-C      transfer to  loads on B
transfofncr      AC  pouer            cspcrIchccs      voltage            failure.                      does not        mint.      UPS1A D,ri steeply            the transient    goes tou                                              close        supply Pernisstves Faul t                                                                            prohibIt    CS C 1$  clcafcd                                                                            breaker froze in 6 cycles;                                                                                  clo>Ing transfer cocptetcd in 12  cycles CS'4 ncsvh<
to If unsfer na Int sullpl y to lnvcl tcf out put
 
r
: 1. Static DC testing was performed on individual chips from the effected circuits in order to characterize Latch-up susceptibility.
Static testing is performed with fixed voltage settings. The testing was performed on the 4049, 4011, 4044 and 4068 devices.
The test scheme included:
A. Output voltage below Vss (Vss is the ground or negative power supply).
B. Output voltage above Vdd (Vdd in the positive voltage power supply).
C. Input voltage above Vdd.
D. Power supply overvoltage. Vss>>Vdd The  testing revealed that permanent physical damage was induced by tests C and D. Test B did not induce latch-up but test A consistently induced latch-up on the 4049 and at higher voltage differentials on the other devices- The 4049 was quite sensitive to this test.
: 2. Voltage Dropout testing, where the Vdd was cut out and restored during time periods ranging from 20 mS to 2 seconds did not result in latch-up behavior on the individual components.
A "breadboard" test circuit was fabricated to simulate a typical circuit path, i.e. a 4044 latch driving a 4049 invertor driving a 4068 gate driving a 4011 gate driving an MC1615 lamp driver.
Slow  rate dropout testing of the test circuit did not result in latch-up or other anomalous behavior.
: 3. Board  level testing has been performed on the A13A21 cards f'rom UPS  units  A, B and G. A stock card has also been tested. A test fixture was fabricated to hold the cards and supply paver and input selection and output monitoring. An MC 1615 lamp driver chip with LED's (light emitting diodes) was connected to the card outputs.
Static boaef testing revealed no anomalies on the A card, a damaged U10 4049 oN the B card, No anomalies on the C card and a failure to set, any of the 4044 latches on the G card.  (Note that latching of the 4044 chips is normal while latch-up is an abnormal condition.)
The. functional failure of the G board has been traced to the Kl relay and/or the SW 1 reset svitch on the circuit board.
Failure simulation testing on the functional A board has revealed that the lighting pattern reported during the incident, whero the lamps on the card were extinguished and "downstream" lamps remained e
 
illuminated, has      been  duplicated by setting the PSF-not latch, lowering the      DC  voltage to approximately 4 VDC and lifting (floating) the      DC  ground for several seconds.      If the DC voltage remains low after the ground fault the lamps on the board will reset and the external lamps (UPS fail, Logic fail and the SSTR lines) will remain illuminated. The simulation conditions are unlikely to be those of the failure event, however,            it demonstrated that the board can operate in an this illogical state.
has been A more complicated failure simulation (approximating the actual event) may produce the same results.
: 4. High Speed transient. testing on the power lines is planned and delayed pending laboratory analysis of the degraded samples discussed    in the following section.
M        C        0 A. NEGATIVE VOLTAGE ON THE OUTPUT OF THE 4049 MILL INVARIABLY CAUSE LATCH-UP-          INJECTING NEGATIVE VOLTAGE INTO THE OUTPUT IS IDENTICAL TO RAISING THE GROUND Vss ABOVE THE OUTPUT.
B. THE INITIALFAILURE CONDITION IN TERMS OF THE LAMP SETTINGS CAN BE DUPLICATED UNDER UNLIKELY CONDITIONS AND MAY BE POSSIBLE UNDER MORE  PLAUSIBLE CIRCUIT CONDITIONS.
The  following samples have      been submitted  for laboratory analysis:
: 1. One    battery pack. Battery pack 1 from UPS 1C.
(2) integrated circuits from a failed A20 card.
n'.
Two                                                        A 4049 and a  4011.
: 3. A    failed  U10 4049  from the A13121,  UPS  B card.
: 4. The U10 4049 from the A13A21 cards from UPS's A and          G
: 5. The  UPS  6  Kl relay and  SWl  switch.
The  following results have been obtained.
: 1. Two (2) of the Three (3) batteries from UPS 1C were dried out.
Water was added and charging did not result in recovery of the cell. It is concluded that the cell failed due old age wearout.
Analysis is continuing on the other two (2) cells.
: 2. The 4011 from the A20 card is electrically good. Internal
 
I J
    ~  ~
I
 
          . inspection of the Die revealed no anomalies.            The 4049 is lj
  ~
    ~
      ~
        ~
              'electrically  bad. A catastrophic failure. Internal inspection of the die revealed severe damage centered on the Vss and Vdd power lines and several input/outputs.      The initiating overstress was introduced on the Vdd or Vss lines as indicated by arc-over damage acoss the oxide between the two power lines.
: 3. Electrical testing of the U10 4049 from A13A21, UPS B revealed that it was not functional.        Internal inspection of the die revealed a fused aluminum metallization line to one part of the internal circuitry. Probing revealed no )unction damage on either side of the fuse site. This damage is characteristic of classic SCR latch-up.
: 4. Electrical testing of the two (2) additional 4049's was performed during circuit board test. The devices were functional.
Internal die examination revealed no damage on either device.
: 5. Electrical testing of the A13A21 circuit board from UPS G revealed that SW1 was intermittently open circuited in the normally closed position. This condition would provide continuous reset signals to the 4044 latches through the K1 relay. The switch was isolated and a good switch was placed across the Kl relay. The circuit board inputs still would no latch the lamps. The Kl relay was removed and testing revealed that    it was electrically good. The findings reveal that either the Kl relay is either intermittently bad or there are other problem components on the circuit board.
Analysis is continuing.
R    0  U  0 A. THE DAMAGE NOTED ON THE 4049 FAILED INTEGRATED CIRCUIT FROM UPS B  WAS  INDUCED ON THE Vss (GROUND) SIDE AND SUGGESTS A GROUND TRANSIENT MAY HAVE OCCURRED. THE DAMAGE ON THE 4049 FROM THE A20
            . BOARD INDICATES THAT THE DAMAGE WAS INITIATED BY A TRANSIENT ON EITHER THE Vdd OR Vss LINE, BUT IT MAY ALSO HAVE BEEN INITIATED BY LATCH"UP.
B. AT LEAST ONE OF THE BATTERIES FAILED DUE TO OLD AGE WEAROUT.
C. THE CAQNE OF THE FAILURE OF THE UPS      G TO  SET THE LATCHES ZS UNKNOWN AT  THIS TIME. THE SW SWITCH HAS BEEN FOUND TO BE DEFECTIVE AND ANALYST'S WILL DETERMINE IF THE COMPONENT IS RELIABILITY RISK.
 
I
                        -UPS lA  1B  1G  TEST
 
==SUMMARY==
 
page 1
 
==Purpose:==
To prove  that the DC logic power for the Exide UPS is powered from the B-phase maintenance supply. The K-5 pickup and drop out voltages and the DC trip-point o=
the DC logic will be recorded for UPSlA, not for UPS13 and UPS1G. The internal batteries will be tested and replaced.
Results Summary:
1.)  On UPS1A, logic UPS1B and UPS1G,    it was  verified that the power supplies are fed from the B-phase DC maintenance    supply.
2.)  The K-5  relay drop out and pick up voltages were recorded  for UPS1A and they were found to be below the trip  point of the DC logic power.
3.)  On UPS1A,  UPS1B,  UPS1G,  the maintenance supply was opened with the    UPS  feeding the loads and no UPS trips occuzredo 4.)  On UPSlA, UPS1B and UPS1G,      the batteries were replaced.
CONC U This test proves that the DC logic power is fed by the B  yhaae maintenance power.        It proves that the internal it proves that batCOries were effectively dead. For UPS1A on a slow transient that. the DC logic power will drop out before the K-5 relay will transfer to UPS power.
 
page 2 Numerical Results:
1.)  The UPS1A  DC  logic trips at <16.7  VDC.  (with.75.6 VAC on input)  .
: 2. ) UPS1A:    K-5  relay drop out  47  VDC K-5  relay pick up - 52  VDC 4.)  The  internal battery voltage  was measured:
UPS1A:    Positive-Negative-UPS1B:    Positive-      0.54 Negative-      6.2 UPS 16:    Positive-      18.3 Negative-      0.69
 
) J 2VBB-UPS1C TEST
 
==SUMMARY==
 
page  1
 
==Purpose:==
To  prove that the DC logic power for the Exide UPS is powered from the B-phase maintenance supply and that a transient occurs on the maintenance supply      it can if effect the DC logic such that  it will trip the unit.
This test is done with the old internal logic batteries and then repeated with new ones. Each of the inverter trips will be tested to verify that each circuit is still  intact except DCOV., An AC input transient to UPS will be simulated to verify that the unit can "ride out" a normal AC input transient without tripping. The K-5 relay pick up and drop out voltages and the DC trip-point of the  DC logic will be recorded.
Results Summary:
1.)  Zt was verified that the DC logic power supplies are fed from the B-phase maintenance supply.
2.)  A  rapid open and closing of the upstream normal AC input breaker to the UPS was done and the unit did not trip or go on battery. No noticeable effect was seen on the UPS output.
3.)  Each  inverter trip circuit except  DCOV was  tested and each functioned as designed.
4.)  Fast transient tests:
With the old batteries  still installed a voltage interruption of 100 - 150 msec duration was given to the AC input to the DC logic of UPS1C. The DC logic was initially at 19.86 VDC. The unit tripped 3 out of 4 times. This was done first with the loads on
        . xaintenance supply and then also with the loads on        UPS power ~
With the new batteries installed there was no trip when the fast transient test was performed 25 successive times. There were no trips but a repeated SCR short alarm occurred which is indicative of noise spikes within the unit.
 
page 2 5.)    The K-5  relay drop out was recorded and was found to  be below the  trip point of the DC logic power.
6.)    Normal transfers were done, UPS to maintenance and maintenance to UPS, with dead batteries and there were no trips of the UPS. The maintenance supply was opened with the UPS feeding the loads and no UPS trips occurred.
CONCLUSZON This test proves that the    DC logic power is fed by the B  phase maintenance    power and that it is susceptible to voltage transients on the maintenance supply. Zt may be susceptible to other transients as well because it is directly tied to maintenance supply. The test DOES NOT prove the level of susceptibility, that is, it does not prove that the transient was of any set voltage or duration.
The test implies that the batteries may have mitigated the trip  but is not conclusive.
Each trip circuit was tested successfully so no    failure to  any of these occurred that caused the trip.
The  fast open/close of the normal AC input breaker proves  that the unit would withstand an AC input transient without failure or without going on battery power.
 
I
'5 ~
 
page  3 Numerical Results:
1.) Fast Transient Tests a.)  W't existin      batteries 1.)  With loads on maintenance:
At 19.86 VDC (90.0 VAC) - ~tri            (150  msec.)
At 19.86 VDC (120 VAC) - ~t          '150      msec.)
2.)  With loads on    UPS  power:
2 Tries,  1 ~t i  (200 msec.)
b.)  W't  new  batter'es-1.)  Approx. 20.0    VDC  -  25  times,
                                                ~no  tri .  (100 msec.  )
2.) The  DC  logic trips at  <  16.9 VDC. (with 84.59        VAC  on  input).
3.) K-5  relay drop out --  45 VAC K-5  relay pick up          ** not recorded 4.) The  following trips tests    were done:
a.)    OV/UV b.)    ACUV c.)    ACOV d.)    DCUV e.)    Frequency  fail f.)    Logic Failure g  )  Power supply failure
: h. ). Clock failure 5.) The  internal battery voltage      was measured:
Positive - +0.6 Negative  -    +0.04
 
4 l ~
5
 
page  4 5.) Xndividual cell voltages:
Batte  Volta  e New Batte  Volta  e 1.)      1. 19                    6.10 2.)      2.48                      6.07 3.)      2.24                      6.10
: 4. )      0.17                      6.09 5.)      0.79                      6.10 6.)      1.78                      6.12
 
V  -UP  D  S  S page
 
==Purpose:==
To  prove that the DC logic power for the Exide UPS is powered from the B-phase maintenance supply and that a transient occurs on the maintenance supply    it can if effect the DC logic such that    it will trip the unit.
This test is done with the old internal logic batteries and then repeated with new ones. The K-5 pickup and drop out voltages and the DC trip-point of the DC logic will be recorded.
Results Summary:
1.)  It  was verified that fed from the B-phase the'C logic maintenance power supplies are supply.
2.)  Fast transient tests; With the old batteries  still installed a voltage interruption of 100 - 150 msec duration was given to the AC input to the DC logic of UPS1D. The DC logic was at 20.9 VDC. The unit would not trip. The AC input voltage to the DC logic was then reduced such that the DC logic was at 20.0 volts. When the test was performed with the DC logic power at 20.0 VDC the unit tripped. This was done first with the loads on maintenance  supply and then also with the loads on    UPS power.
With the new batteries installed there was no trip when the fast transient test was performed though there was significant hits shown on the DC logic power bus as seen by the  oscilloscope.
3.)  The K-5  relay drop out and pick up voltages were recorded and they were found to be below the trip point
        . of the DC logic power.
4.)  Normal transfers were done, UPS to maintenance and maintenance to UPS, with dead batteries and there were no trips of the UPS. The maintenance supply was opened with the UPS feeding the loads and no UPS trips occurred.
 
I a
 
pl lt i1 4i    V
      , ~
page  2 CONC This test proves that the DC logic power is fed by the B phase maintenance power and that  it is susceptible to voltage transients on the maintenance supply. It may be susceptible to other transients as well because  it is directly tied to maintenance supply. The test DOES NOT prove the level of susceptibility, that is,  it does not, prove that the transient was of any set voltage or duration.
The test implies that the batteries may have mitigated the trip but that is not conclusive.
 
ta 0
 
page  3 Numerical Results:
1.) Fast Transient Tests a.) W't e istin        batteries With loads on maintenance:
At 20.9 VDC  five tries, no trips.
At 20.7 VDC - one try, one ~tri .          (150 msec.)
2.)  With loads on UPS power:
At 20.06 VDC - one ~t '      (100 msec.)
b.)  W't  new  batteries 1.)  At 20.05  VDC - Five tries, hit
                                                    ~so  tri s.
noticeable  DC      on each    transient.
2.) The  DC  logic trips at    <17.3 VDC. (with 84.5    VAC on    input).
3.) K-5  relay drop out --  42 VDC K-5  relay pick up      55 VDC 4.) The  internal battery voltage    was measured:
Positive-      +0.6 Negative-      +0.14        (the negative battery set        was actually slightly positive).
5.) individual cell voltages:
t  V  tae                w  Batte      Vo ta  e
                .254                                    6 '0 2.)          .570                                    6 '6 3.)        1.03                                      6 ~ 10 4~)          .07                                      6 '0 5.)        1 ~ 17                                    6 '3
 
t 0
 
I t
6.) 1.39 6 '9
 
1 resulted until such time the power to these UPS's was restored. However, one or more of the other lighting systems namely, emergency, normal and 8 hour battery pack were available in these a'reas during this event.
The stairwells are provided with essential lighting only except where 8 hour battery pack lighting is added for Appendix R compliance. Illumination to these stairwells was not available due to loss of normal UPS.
The 8 hour battery pack lighting did not energize because there was no loss of normal power.
Event Evaluation The root cause of loss of power from normal UPS is evaluated separately in another report. During the event, some areas of the plant lost partial illuminations provided by essential lighting for sometime. Areas critical for safe shutdown where this lighting are identified are provided in Attachment 7.
During this event the plant was safely shutdown from the control room. Because the control room is provided with adequate lighting without the essential lighting, loss of essential lighting did not adversely affect the operator actions needed to bring the plant to safe shutdown.
The access    route used by the operators during this event for restoration of the normal UPS power (Attachment 8) supplies was illuminated from normal lighting except for the stairwell where portable handheld lights were used.      (FSAR Sec. 9.5.3.3 allows the use of portable lighting in the form of handheld flashlights for short excursions into the plant). The normal UPS locations were illuminated by normal lighting. Therefore, restoration of UPS power was unaffected by loss of essential lighting. Even though the essential and egress lighting are powered by three normal UPS's,          this event due to multiple
    'ailures of allduring, normal UPS's, essential and egress lighting  systems were not  available. The existing essential  and egress  lighting design is  adequate, however, the root cause of the multiple failures of the normal UPS's will be determined/evaluated and appropriate corrective action taken    if required to ensure that multiple normal UPS's failure will not reoccur.
reliability of stairwell lighting where will The proposed    plant modification 89-042      enhance the 8 hour battery pack    lighting is provided.
NSK2 14
 
Status of Normal Reactor Buildin Li htin During the event on August 13, 1991,  it was reported by the operators in the reactor building that some areas of the reactor building lost lighting momentarily.
Event Evaluation Normal lighting for reactor building general areas, work area's and electrical equipment areas is provided with low wattage high pressure sodium vapor lights. In the event of power interruptions or voltage dip lasting for more than one cycle, these fixtures extinguish and do not restart until the lamp cools and pressure decreases. When a power supply to continuously energized sodium vapor light is interrupted,    it has a cooldown period before a restrike of the lighting can occur. The cooldown period depends upon the rating of the light bulbs. During the event, the emergency distribution system experienced a,transient due to the fault on the Phase B main transformer. During the event, the Reactors Building normal lighting in certain areas where these high pressure sodium vapor fixtures are provided, was interrupted for approximately 30 seconds. This momentary loss of lighting was due to the inherent design of low wattage high pressure sodium vapor lighting which requires cooldown period prior to restrike whenever power is interrupted. The same scenario could occur in the plant wherever power supply to high pressure sodium vapor fixture is interrupted momentarily, however, there is no indication of such a loss in other areas of the plant. Therefore, it is consistent with NMP2 lighting design and USAR Section 9.5.3.
h) Grou    9 Isolation Valves Closure The group 9 primary containment isolation valves are part of containment purge system. These valves are listed in Technical Specification Table 3.6.3-1, Page 3/4 6-24 and USAR Table 6.2.56, Page  ll  of 24. The function of group 9 isolation valves is to limit the potential release of radioactive materials from primary containment. These isolation valves are opened during power operation only at infrequent intervals to allow injection of nitrogen into primary containment to inert or de-inert the primary containment at a desired pressure. These valves, if open, receive signal to close  if any of the following happen:
NSK2 15
 
a)  High radiation through standby gas treatment system (SGTS). The SGTS radiation monitor located in the main stack is designed to continuously monitor offsite release and provide isolation signals to these isolation valves.
b)    High drywell pressure.
c)    Reactor low water level.
d)    Manual  isolation of  main steam isolation valves.
Event Evaluation During  this event, the group 9 primary containment isolation valves closed. This isolation is the safe mode of operation limiting potential releases of radioactive material from primary containment.
The initiating condition for these valves occurred as a result of loss of power to radiation monitor 2GTS-RE105 when UPS power to the DRMS computer was interrupted.
The actual isolation occurred when the logic was reenergized upon restoration of the UPS power supply to the monitor's auxiliary relay circuit. Therefore, group 9 isolation valves closed as designed and is consistent with USAR Section 6.2.5.2.4, Page 6.2-77.
j) Reactor Manual Control    S stem The  reactor manual control system (RMCS) provides the operator with means to make changes in nuclear reactivity via the manipulation of control rods so that reactor power level and core power distribution can be controlled. This system is a power generation system and is not classified as safety related.      The RMCS receives electrical power from the 120 V AC normal UPS.
The RMCS does not include any of the circuitry or devices used to automatically or manually scram the reactor. The RMCS control and position indication circuitry is not required for any plant safety function nor is  it required to operate during any associated DBA or transient occurrence. The reactor manual control circuitry is required to operate only in the normal plant environment during normal power generation operations. The discussion of RMCS is consistent with USAR Sections 7.7.1.1, Pages 7.7-1, 2, 14.
NSK2 16
 
Event Anal sis The  RMCS was lost during this event because its power source, the normal nonsafety related UPS, was lost.
The loss of RMCS is not a concern during this event.
Since the plant was automatically scrammed during this event, the RMCS need not perform any function after the scram. This RMCS is used by operator only during normal plant operations. Therefore, if the plant had not automatically scrammed during the event, loss of RMCS would not have caused a safety concern based upon the following:
EOP's  provide guidance to the operator under situations involving failure to scram, and
: 2)    various ATWS mitigating design aspects of the plant were fully operable throughout the event.
Although this system was lost'during this event, its importance diminished once the automatic scram occurred. Therefore it is concluded that the RMCS function was consistent with USAR Section 7.7.1.1.
k) Feedwater Control  S stem The feedwater  control system controls the flow of feedwater into the reactor vessel to maintain the vessel water level within predetermined limits during all normal plant operating modes. During normal plant operation, the feedwater control system automatically regulates feedwater flow into the reactor vessel. The system can be manually operated. The feedwater flow control instrumentation measures the water level in the reactor vessel, the feedwater flow rate into the reactor vessel and the steam flow rate from the reactor vessel. During automatic operation, these three measurements are used for controlling feedwater flow.
The feedwater control system receives its normal power supply from the normal UPS. The feedwater control system is designed to lock in its last position upon a loss of power to its control electronics. The feedwater control system is discussed in    USAR  Section 7.7.-1.3, Page 7.7-23.
Event Anal sis During this event, upon loss of the normal UPS's, the feedwater control system performed as designed and failed in its last position. Therefore,    it is concluded that the feedwater control system function was consistent with USAR Section 7.7.1.3.
NSK2 17
 
h
'1
 
l)  Feedwater  Pum  Tri Feedwater  is provided to the Reactor Pressure Vessel (RPV) via  the Condensate Pumps', Condensate Booster Pumps and  the Reactor Feed Pumps shown in Attachment 9.
The Condensate Pump draws condensate water from the Condenser and provides the necessary Net Positive Suction Head (NPSH) for the Booster Pumps. The Condensate Booster Pumps provide the necessary NPSH for the Reactor Feed Pumps. A minimum flow control header is provided off the discharge header of each pump to ensure that the minimum flow is maintained through the associated pump. The minimum flow control valves and associated instrumentation actuates to maintain this minimum flow. The main feedwater control valves (LV10), located on the discharge header of the Reactor Feed Pumps, modulate to control reactor water level.
The feedwater control system is powered by normal UPS power supplies. The above discussion is consistent with USAR Section 10.4.7.
Event Evaluation It  was reported during this event that feedwater pumps tripped. An evaluation of this condition reveals that reported happenings are consistent with the system as designed and is in consistence with USAR Section 10.4.7. The instrumentation controlling the minimum flow recirculation valves on the condensate, condensate booster and the feedwater pumps is powered from the normal UPS's. These instruments are also designed to open the valve upon loss of power in order to protect the pumps. Upon loss of normal UPS, the feedwater control valves fail locked in their last position.
Following the turbine trip, an ATWS signal would attempt to drive the feedwater control valves closed, however since an ATWS signal was not present, this did not occur. With the feedwater control valves failed locked and the minimum flow control valves (FV2) driven full open, feedwater flow increases and approaches pump run-out. The Reactor Feed Pump NPSH decreases to the low-low pressure trip point, tripping the Feedwater Pumps. The Feedwater pump control circuit does not utilize an auto transfer    logic to standby Feedwater Pump; therefore, feedwater flow is lost.      The instrumentation circuits for all other minimum flow control valves are also powered by normal UPS power supplies. These valves all fail in the open position with the loss of UPS and contribute to the loss of Feedwater pump and condensate booster pump. This is consistent with USAR Section 10.4.7.
NSK2 18
 
  'I I
 
m)  Annunciators and  Com uters The plant annunciator system provides information to the plant operators by windows located on the main operator panelboards and on back panels within the Power Generation Control Complex (PGCC). This system does not include annunciators on local panels throughout the plant and on special panels, e.g., fire protection, within the PGCC. The plant annunciator system is non-safety related and is connected to the normal power distribution system through normal UPS's. The plant annunciator system is not discussed in the USAR.
Several computer displays, with inter-active keyboards, are located in the PGCC. These displays are from the following computer systems.
PMS        Plant Process Computer LWS        Liquid Radwaste Computer, which has the following subsystems:
LWS      Liquid Radwaste Control GENTEMP  Generator Temperature Monitoring ERF      Emergency  Parameter Display System SPDS      Safety Parameter Display System DRMS      Digital Radiation Monitoring System 3D Monicore    A system used primarily for core calculations and monitoring In addition, noble gas information is provided to the plant operators from the GEMS (Gaseous Effluent Monitoring System) computer by chart recorders on a back panel; and the operators have access to the    GETARS (General Electric Transient Analysis & Recording System) computer.
All of the above computer systems are non-safety related and are connected to the normal power distribution systems through normal UPS's. There      are some  safety related radiation monitoring skids that provide input to the DRMS computer. However, these skids also provide safety related indication in the PGCC that is independent of the DRMS computer.
NSK2 19
 
The  Plant Process Computer is discussed in Section 7.7.1.6 of the USAR, where  it computer is non-safety related.
is mentioned that the USAR Section 11.2.1.2 covers the Liquid Radwaste System design basis and states that the power supply for all Radwaste System components is provided from non-Class 1E power sources. This is compatible with the Safety-Parameter Display requirements since NUREG-0737, Supplement 1 states that the SPDS need not be qualified to Class 1E requirements.
The process and effluent radiological monitoring and sampling systems, which include the DRMS and GEMS computers, are discussed in USAR Section 11.5. This section defines which monitors are safety related and which are non-safety related. The DRMS and GEMS design complies with this USAR section.
Area radiation and airborne radioactivity monitoring instrumentation, which include the DRMS and GEMS computers, are discussed in USAR Section 12.3.4.1.
This section defines which monitors are safety related and which are non-safety related. The DRMS and GEMS design complies with this USAR section.
A description of the 3D Monicore computer system was added to USAR Section 7.7.1.6 by LDCN U-1235. This LDCN states that the 3D Monicore system is non-safety related.
The designation of the computer systems mentioned above as non-safety related is consistent with the explanation of the Uninterruptible Power Supply System in USAR Section 8.3.1.1.2. In this section    it stated that 2VBB-UPS1A feeds the radwaste computer is hardware, 2VBB-UPS1B feeds local non-safety related radiation monitoring microprocessors, and 2VBB-UPS1G feeds plant computer loads.
Event Evaluation With the loss of the normal UPS's, the plant annunciation system and the computer systems listed above became inoperative due to the loss of power.
This is consistent with the plant design and the description of the plant in the USAR. These systems are non-safety related and, hence, are not required to shut down the plant following a design basis event.
NSK2 20
 
CONCLUSION Based on responses the above evaluation, during  the event  on it  can be concluded that the plant 8/13/91 is consistent with USAR descriptions..
RECOMMENDATIONS Based on  the above evaluation, the      following long term recommendations are provided.
: 1)  Plant Oscillograph  The in-plant oscillograph should be replaced  with a more reliable and functional unit.
If  this oscillograph was functional during the event on 8/13/91, adequate data could have been available to accurately evaluate the cause of the disturbance.
: 2)  Essential Lighting  The proposed modification 89-042 should be implemented as soon as possible to enhance the rel'iability of stairwell lighting where 8 hour battery pack lighting is provided.
: 3)  Control Power Supplies  During the Electrical Distribution System evaluation,      it was revealed that most of the systems important to plant operations such as feedwater system, annunciation system, etc, receive their control power from either normal UPS 1A, 1B or both. It is recommended that control power supplies for these systems be evaluated and reconfigured to avoid plant transient due to loss of single normal UPS.
: 4)    Main Generator visual inspection Itbe isperformed recommended that of the a thorough generator stator and winding support system during the next refueling outage (see Attachment 10).
NSK2
 
345KV TO Sl  "A STATION LINE 23)                                                          ATTACHMENT'-1 345/25KV 115KV SOURCE  'A'LINE 5)            UNIT                                SPARE      115KV SOURCE    '8'LINE    6)      115KV SOURCE  'B'OR TRANSF.
498HVA EACH UNIT
                                                                                                                              '8'UX 25KV~                                    42/56/79MVA                              'A'2/56/78HVA RESERVE
                                                                                  ~NORMAL STA. TRANSF.
24.')KV/13.8KV                RESERVE                              BOILER BANK 'A'                                                                                                  BANK 199-59/59HVA WJGKV NO        CUB ONLY                                            CUB. ONLY 2NPS-SWG991                                                2NPS-SWG993 13.BKV NORHAL                                                                                                          .
                                                                                                                                            ~ 13.BKV AUX. BOILER BUS 2NPS-SWG892 AUX. TRANSF.                                                      AUX. TRANSF. NC                        NO NORHAL 4 J69KV 2NNS-6WG914 4 J6KV 2NNS-SWGBII        2NNS-SWG812            2NNS-SWG913 2NNS-SWG91  5 WJGKV ~
0.16K V  NO STUB BUS                                                        STUB BUS CUIL ONLY                                                          NC iJ69KV OIV.I EHERGENCY 2ENSiSWGIB)                        2ENS~SWGI92
                                                                              ~    4.169KV DIV.3 EHERGENCY BUS 2ENS~SWG193 4.168KV OIV.2 EMERGENCY BUS EGI OIV.1 4489KW EG2 DIVE                                                        EG3  BID 2688K W                                                        4489KW ONSITE A.C. POWER SUPPLY
 
5 BIIKLE LQK      FOR  NN-IE tPSIA IILICJOol(LI)L3(L38 2NPS-SWGB8)    ONV)      2NPS-SWG883      03.8KV)                                                        2NPS-SWGBBI a@SKY) 2NPS-SWGM3 (688 V)          2NJS-US4                              (688 V) 2NJS-US3                          2NJS-US3                        2VBB-TRSI                                                                      2NJS-USI              2NJS-US4 BUS A                              BUS 8                          AUTOHATIC                                                                      BUS C                  BUS 8 TRANSFER SWITCH (688 V)                (6MV)                                        (688 Vl                                                  (688V)                (688V)
                                                                                                                            ~ INTERNAL 2NHS-NCC996            2LAT-PN.388            2VBB-PNL381                                                                    BATTERY NO                2LAT-PNL188          2NJS-PIL482 BUS A                                                                                                                      ALTERNATE N                                                                        N                  N AS                    UPS                    UPS                    UPS                    UPS                  UPS      BAT-IC      UPS      BAT-18      UPS IO      BAT-IA      IC          BAT-IA      IA        BAT-IC                BAT-IC                            IN ~                  3A                    3B BAT IB A                      A                                                                  N (6BSV)                (688 V)                          (688 V)                (6MV)                  (688 V)              (688 V) 2NJS-US6              2NJS-USS                                                                      2NJS-US6                  2NJS-PNL')81          2NJS-PNL5M            2NJS-PNL688 HJGKV)                  H J6KV)                                                  (4 JSKV)              (6MV)                  (688V)                (6MV) 2%S-SWGBIS            2NNS-SWG914                                                                2NNS-SWG815                    2NHS-HCCB)6            2NJS-USS              2NJS-US6 BUS B 03J)KV)                03.8KV)                                                  0XSKV)                (689 V)              (4 J6KV)              H J6KV) 2tfS-SWGM3            2NPS-SWGBBI                                              2NPS-SWG883                                      2NJ6-US')              2NNS-SWG814          2NNS-SWG915 BUS 8
                                                                            -                                                                OXSKV)                03J)KV)
SINGLE LINE FOR CLASS IE LES          2(L2B 2NPS-SWMBI            2NPS-SWG883 H JSKV)                H JQOO 2ENSiSWGIBI            2ENS+SWG)83 (688 V)                (6MV) 2E JSiUSI              2E JSiUS3 (6MV) 2EJS+PNLIBBA          2E JSiPNL38BA BAT-2A        UPS      BAT-28      UPS 2A                    28 (6MV)                  (688 V) 2LACiPNLIMA            2LACiPNL3M8 (688 V)                (688V) 2EJSiUSI              2EJSiUS3 (4 J6KV)                H JGKV) 2ENSiSWGI91            2ENSiSWGI93
 
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      &89-SA                  25989-5A              258M-SA                      25889-5A                                                                                      I CORE GAP      39-1 39-1              39                      8-                        39-4 39-c      P864      BDO                                          86-1 2SPHXBI                HAA                                                                              HAA                    87                          IPBSS~HEA PB65  BDD I    PBSS~HEA P865      HFA-45988-5A 2SPUY82 2STX-XNSI 2GHS-Gl GEN.
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6-P867~HEA 15889-SA                      I 2SPGZB2 pe67      psc  z2-2YxcNBI            IP867~ MFA 45989-5A CORE GAP 2SPUY92                                                                                      AwhcHeem g PACjp        g~g ATTACHHENT Q
 
LIST  OF PROTECTIVE RELAY ACTUATED ON AUGUST 13        1991 Unit Protection Alt    1 Protective Rela            Lockout Rela                  Action            Ref. Dwg, 87-2SPMX01                  86-1-2SPUX01        ~ Initiate Turbine Trip  ESK-8SPU01 Main Transformer            86-2-2SPUX02        ~ Initiate Fast Transfer ESK-8SPU02 Differential                                    to Reserve Station  ESK-5NPS13 Protection Relay                                Transformer          ESK-5NPS14 Unit Protection Alt    2 Protective Rela            Lockout Rela                Action 87-2SPUY02                  86-1-2SPUY01      ~ Initiate Turbine Trip    ESK-8SPU01 Unit Differential          86-2-2SPUY01      ~ Initiate Fast Transfer  ESK-8SPU03 Protection Relay                                to Reserve Station  ESK-5NPS13 Transformer          ESK-5NPS14 63-2SPMY01                  86-1-2SPUY01        ~ Initiate Turbine Trip ESK-8SPU03 Fault Pressure              86-2-2SPUY01        ~ Initiate Fast Transfer      Sh. 2 Transformer                                      to Reserve Station  ESK-8SPU03 Transformer              Sh. 1 ESK-5NPS13 ESK-5NPS14 Unit Protection  Backu Protective Rela            Lockout Rela                  Action 50/51N                    86-1-2SPUZ01      ~ Initiate Turbine Trip    ESK-8SPU04 2SPMZ01                    86-2-2SPUZ01      ~  Initiate Slow Transfer  ESK-5NPS13 Protection Relay                                After 30 Sec.        ESK-5NPS14 Block Fast Transfer After  6 Cycles Generator Protection Protective Rela            Lockout Rela                  Action            Ref,D~
Gen. Phase  OC During    86-1-2SPGZ01      ~  Initiate Turbine Trip    ESK-8SPG01 Startup                86-3-2SPGZ01    ~  Initiate Slow Transfer    ESK-8SPG04 50-2SPGZ02                                          After 30 Sec.        ESK-5NPS13 Block Fast Transfer  ESK-5NPS14
                                          ~  This Relay Picks Up Only When Unit is Off Line HSKl
 
II AXTACEKNT 3 PAGE 3 of  3 Degraded Voltage Switch ear  Lockout Rela          Action                Ref. Dw 2ENS*SWG103  27BA-2ENSB24  No Action Took Place      ESK-5ENS18 27BB-2ENSB24  Degraded Voltage Stays    ESK-8ENS02 27BC-2ENSB24      During Fault Conditions 2ENS*SWG101  27BA-2ENSA24  No  Action Took Place    ESK-5ENS14 27BB-2ENSA24  Degraded Voltage Stays    ESK-8ENS01 27BC-2ENSA24      During Fault Conditions 2ENS*SWG102  27BA-2ENSC08  No  Action Took Place    807E183TY 27BB-2ENSC08  Degraded Voltage Stays      Sh 7 27BC-2ENSC08      During Fault Conditions NSK1
 
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                        .            LAk~          >~~~  Nine Mile Point Nuclear    station To        Distr                                    OATL 15  August 91    FfLX COal Nine Mile Point Fire protection Program Post Event Xnterviews After interviews              conducted today with Fir e Chief Bernie Harvey, and    Firemen          Fat Brennan and Nark Locurcio, and concurrence with Terry Vermilyea, System Expert Pire Detection and John Pavlicko of Caution Equipment Enc., X have reached the following conclusions.
1 ~  Of the 20 fire panels at Unit 2, 18 maintained a normal power supply o 2a. Two Cire panels LFCP113 and 123 transferred to internal battery  backup.'b.
These two panels wb'ile on          battery will still function normally as long as the 120 VAC is            available in the LPCF, which    it was.
There was no interruption or decrease of fire proteotioni detection/suppression at the local fire panels.
Fire Panels 849 and 200/1 being fed from QN did have a power interruption. This would have left the control switches operable at Panel 849, (as they are fed from LPCP), but control Room with no Cire annunciation.              Any fire suppression/indication could also have been  initiated locally.
ABA: dlc T, Tomlinson A. Julka (FAX 7225            - SN)
D. Pringle
 
QJQ 15 '91  15' ttt tKT Na&#xc3;C Ss ~  DTS
                                                    +~AD-+8'~
P.3 g7 INTSHNAL COhllSNKNDRNCK                                        4 CLopf INN'tMAeSN pg4gy      Lo              en ~                        Nine  M5.1e  Point Nuclear Station To        FiI                                        15 'August Ql    RLR COOI SUSJCCT Nin<<Mile Point, Unit 2 Fire Protection Program Feet Rvent 8/13/91 Interviews
          ?ire Dept. Personnel Interviews(        Poet  Iveat of august    13( 1901 Bernie Harvey - Chief ln early fox coverage, interviewed for loss cf power in Contxol Building. Lights blinked, loud noise                (louder than ever heard in plant),      was  in  Fire  Dept. office(  told  shift  to get  out into  plant.
Pat Wilson was in Rx Bldg> switched radios to Channel 10, standard Fire Dept. practice      if suspect lose of repeator.
Pat Bxennan was in the Foam Room and proceeded to the Chief(s desk.
Chief Harvey heard fire panel alarming when he got to Control Building. Went past Fir~ Panel 114 in Turbine buildf.ng passageway(
no audible alarms( seemed normal.
Mar}c Locurclo went to Panel 12d - 214 elev. while Chief Harvey went to Panel 127>> 244 elev. t these were sounding trouble alarm            and D&
normal  - no was clear.      Went past Panels 120( 121 ( 128 f they      were audible.
Pxior to Site Aea Emergency (SAE) message and evacuation being announced - Pat brennan reported Panels R.B. normal, called cn Gaitronics - had to silence Panels 113 on I, B. 250 and than silenced all Fanele in R.Be ( Panels 101, 103( 104( 105( 10d( 10>
and XQ8.
Chier Harvey wae Cofnp to tri~e etage wet ln R h. a.nd have aan in R.s. cnarde Lynn Roon, accocpanled hy Larry cchaner, called hfa supervisor, when they saw transformer blow.
Chief Harvey wou14 have liked tO get to transfcrmer quf.oker for
            ".ire evaluation.
OV41QLCiOt1 He feels    it  was at least one hour be for e,'
                                                                                    'n''l e
ch'f    Harvey feels Fire Dept. should have been part of investigation/inspection team with Operationse
 
QJQ f5 '9t 15~41 tt% JKT l%WT & CCttl DTS P.4 5'ff'Acp-m~y- g p~r-  gg p 1991  1'nterviev (Cont '4) g Pat Pat  m inoffice Chief"'s foam  Room and approximately  0550>
asked what noise was.
heard loud noise, vent to Lighting dimmed, one string of lights      off (NOTE: these feed fram Emergency - UPS should have gone    off)
Then he      vent on rover - heard alarms - which vere on vater treatment system panel, then vent to Panel 123. There were no displays on DAX panel, vas blank no lights vere on. Power lights vore off. Trouhle Light blinking.
Rent  to T.S, 261 NN, eigned sheet,            stairtower dark'no problem, knew vay around), Turbine Traok Bay            4imly lighted.
Wont  to T.S. 306  -  OK,  sign>>4 sheet T B    Svgr 277      OK) signed sheet T.Q. 250 by Feedpumps - noted not running by Panel 113 - no Lights on, no audible or trouble alarm estimat>>s time approximately 0605 Continued raver rounds to Panel 106              South Stairtover R.S. 249 vas alarming display sai4 "on internal clock" had tvo troubles displayed Went  to  Q.B. 215        tire panel 103 alarming      - silenced R. B. 190      Fir~  panel 101 alarming      silenced both panels were in trouble - unknovn R.B. 175        Signed sheet R.B. 261        SBCTS  - OX Panel 105 - silenced troubles CQ2 Room, about t?)is time, evacuation alarm sounded went to Unit 2 Control Room assembly point Walked around with Pat Brennan on 8-15-91 ta Panel 123 and Panel 113, power on light vas burned out on Panel 123. "Power on" Light was on, on Panel 113        ~
 
.AJG 15 '91 15:41  N1 le MGKI Sc COPFl DTS                                          P.5 Aff~Alm8Ng g P08 +opp post  I+gt kuy.
C 13, 1991 Xnterview (Cont'4)
Mark ZcNtok,o      (Calle4 at home)
Has located in the Fire Dept. Office when lights flickered and noise was heard. Radio communication was gone, Hear Here was out.
Chief Harvey directed personnel to cover vital areas. Pat wilson was in RX Bldg. Pat Brennan was roving T.B. Bernie f Hark were tc cover Control Bldg.
Trip to C.B. uneventful Panels Passed in route)
Panel 114 Elect. Bay Elv.
120 C. 5 Elv. 261
                              ~
261'anel Normal 128 C.5. Elv. 261~
Panel 121 C. B. Elv, 125 C.B. Zlv.
214'ormal 261'anel
                                                'anel Normal Normal Normal 127 C.B. Elv.      261'anel Trouble, Horn sounding-2i4'anel SU,enaod 126  C.B. Elv.                            Trouble Horn sounding-lilenoed, also an amber light was  lit on panel Checked    valve room on C.b. elv. 2ii'ight was on in room. No indication of system actuation.
stairwells were dark, Elv, 261'.B. was dark. s.A.E. announcement and reported to Control Room.
 
I A<7~mgur 7                      pt)c,p k~
NMP2 LIGHTING SYSTEM POWER SOURCE AND MINIM)St ILLUHINATIONAVAILABLE - CRIT]CAL AREAS                                          PAGE    I MODES OF OPERATION TRANSIENT LOCA  St SEISMIC WITH LOOP                  WITHOUT LOOP MIN.                  X      MIN.                X                              X OF                          X OF ILLIIL                                                                  HIN.                                                    MIN. ESSENTIAL SIXRCE6 PROVIDED BY POWER AVAIL (FOOT POWER SDUIKES
                                                                  ~~~
BY POWER AVAIL.
                                                                          <FOOT POWER SIXRCES PROVIDED BY POWER AVAII
                                                                                                          )FOOT  ~ES POWER    PROVIDED (FOOT POWER SOURCES PROVIDED  AVAIL.
(FOOT LIGHTING UPS PAtEL SIXRCE  CAN)LE)              SIXRCE  CANDLE)
SOURCE    CANDLE)
SOURCE  CANDLE)
SOURCE  CANDLE)      IL CIXITROL ROOH N)RMAL 58                                              NORMAL                                                      NORHAL    58                            S NXR BATT. PACK IDPERATING                                                                                                                                                                          HANXACTIRER-EXIDI AREA 5 RELAY ESSENTIAL            )9                                                                                                                                                        (TYPICAL)
ESSENTIAL    18              ESSENTIAL                      ESSENTIAL                  ESSENTIAL  18 PANEL AREA) 159 CONTROL            BLDL EHE ROE    49                                            EMERGE                                                                  48
                                  ~
EL.                                                                                                                                          EHERGENC 336'E-65E 8 NXR                      8 NXR                        8 NXR                          8 NXR                        S NXR BAT.PACK                    BAT. PACK                    BAT+ PACK                      BATo PACK                  BAT.PACK  NONE CONTROL ROON HORHAL                189                                                                                                                                                  N THE LIGHTING MRTM-SOUTH                                                                                                                                                                                WINGS, CIRCUITS CDRMDORS)                                                                                                                                                                            TARTING WITH AN 'N ICATE NRMAL POWI CONTROL            BLDL                                                                                                                                                                WITH A %'H)ICATE EL    3P&'E-&5E                                                                                                                                                                        ESSENTIAL POWER, WIT)
AN 'E'INDICATE 8 NXR                      8 NXR                        S NXR                          S NXR                        S  NXR                                EMERGEN:Y POWER.
BAT.PAtx NONE              BAT. PACK                    BAT. PACK                      BAT+ PACK                  BAT.PA)X NRHAL    58                NORHAL    58                NORHAL                          NORHAL                    NORMAL      58                2VBB-UPSID CONTROL ROOM (SHIFT SLPERVISOR                                        ESSENTIAL  18                ESSE NTI                                                    ESSENTIAL  18 OFFICE)                                                                                              16                          16 CINTROL BLDL PAMPAS)
ELo 3P&'E-65E EMERGENC                        EHERGE                      EMERGENC    i8 S NXR                      S NXR                        S NXR                          S NXR                        S NXR BAT.PA)X NONE              BAT. PACK                    BAT+ PACK                      BAT. PACK                  BAT. PACK RELAY AND                                      NORHAL      58                NORHAL                                                                                  2VBB-UPSID CO)4'UTER ROOM            RELAY                            ESSENTIAL  18                ESSENTIAL                      ESSENTIAL                  ESSENTIAL  18 CONTROL            BLDL                            EMERGENC    49                                                EHERGE                      EMERGENC    <9 EL  28F-6'E~
S NXR                        S NXR                        S NXR                          S NXR                        S NXR BAT+ PACK                  BAT. PACK                    BAT. PACK  YES                  BAT. PACK                  BAT. PACK NORHAL      'Q                                                                                                          2VBB-UPSID RELAY AND COtPUZER CQ4%6EA                                          ESSENTIAL  18                ESSENTIA.                                                  ESSENTIAL  18 IKXNO CONTROL BLDG.
EL  288'-6'E-650 S NXR                      8 NXR                        S NXR                          S  NXR                      8'NXR BAT PACK                    BAT. PACK                    BATe PACK                      BAT+ PACK YES              BAT+ PACK
 
AtrocmC~r 7                      PAcEX,~<<
                                                                                                                                                                                'MP2 LIGHTING SYSTEM POWER SOURCE AND MINIMUM ILLUMINATIONAVAILABLE                                                      PAGE  2 HOOES OF OPERATIDN TRANSIENT LOCA  tt SEIS)GC WITH LOOP                  WITHOUT LOOP
                    ~R It OF ILLLSL  MIN.              2 DF ILLLSL 2  OF ILLLSL  Hl)L                  / OF ILLUM    MIN. ESSENTIAL PRDVIOED  AVAIL.          PRLMDED    AVAIL    POWER                AVAIL. POWER            AVAIL    POWER                AVAIL. LIGHTING SOURCES            LFOOT                        LFOOT                                            PROVIDED                      PROVIDED BY POWER                                      SDLRCES                  LFOOT  SOURCES            LFDOT  SOURCES                LFOOT  UPS PANEL SOLSCE CQOLE)            BY POWER SOURCE C~E)              BY POWER SOURCE    CAN)LE)          BY POWER SOURCE  CANDLE)
BY POWER SOURCE  CANDLE)      IIL RELAY AN)                                                              NORMAL                                                      NORHAL      98                2VBB-ASS CQ%'UTER ROOM    ESSENTIAL  18                                          ESSENTIAL LCLXLRIDLRS)
ESSENTIAL    18 CONTROL BLDG.
EL  288'-6'E-65D S NXR                      S NOLR                      S  NXR                          S NXR                      S HOLR BAT. PAIX                  BAT. PACK                    BAT. PACK                      BAT. PACK  YES              BAT. PACK DIESEL      N)RMAL  78                NORHAL  78                NORHAL                          NORHAL                      NORMAL      78                2VBB-UPSID GEtKRATOR BUILDING                                ESSENTIAL 18                ESSENTIAL                                                  ESSENTlAL    18 tWORKING AREA) 28
                            ~
EHERGE                                                      EME ROE NC EL    261'E-6BC S NXR                      S NXR                      S NOLR                          S NXR                      S HOLR BAT.PA)X                  BAT. PACK                    BAT. PACK  YES                BAT. PACK                  BAT. PACK NORHAL    78              NORMAL    78                NORHAL                        NORHAL                      NORMAL      78                2VBB-UPSID DIESEL GEtKMOR BLBLDING      ESSENTIAL 18              ESSENTIAL 18                ESSENTIAL                      ESSENTIAL                  ESSENTIAL    18 LELECTRICAL EQ)IPMENT                                                                                                                                                  38 AREA)      EMERGE    28              EMERGENC  28                                                                            EHERGENC    28 EL.                S NOLR                    S NXR                      S NOIR                          S HOLR                      S HOLR BAT.PAtx N 261'E-6BC BAT. PACK                    BAT. PACK                      BAT, PACK                  BAT. PACK DIESEL    NORHAL    98              NORMAL    98                NORHAL                        NORMAL                      NORHAL      98                2VBB"UPSIO GENERATOR BUILDING      ESSENTIAL 18              ESSENT)AL 18                ESSENTIAL                      ESSENTIAL                  ESSENTIAL    18 LGENERAL AREA)
EL    261'E-68C S NXR BAT.PALX  ~                S NXR BAT. PACK S NOLR BAT. PACK  YES                  S NXR BAT. PACK YES                S NOtR BAT.PaX
 
11 HHP2 LIGHTING SYSTEH POWER SOURCE AND HINIHJH ILLUHINATIONAVAILABLE                                                        PAGE  3
                                                                                    . HXKS    OF OPERATION TRANSIENT LOCA  8 SEISHIC WITH LOOP                  WITHOUT LOOP 2  OF                        2        Hl)L                2  OF ILLUH.      HIlL                2        HIN.                I  OF HIN. ESSENTIAL POWER                      POWER                AVAIL. POWER      PROVIDED    AVAIL+  POWER      PROVIDED  AVAIL. POWER    PROVIDED  AVAIL. LIGHTIW SO(SCES PROVIDED BY POWER  (FOOT  SOURCES I ROY)GEO BY POWER  (FOOT  SOURCES    BY POWER                        BY POWER  (FOOT CANDLE)
S~ES      BY POWER    (FOOT CANDLE)
UPS PAtKL IIL REHARKS CA)b)LE)                                          SOURCE CANDLE)              SO(SCE                      SOURCE SOURCE                        SOURCE NORHAL    YES REHOTE SHUT DOWN ROOH CONTROL BLDL                            16.5                                                          IL5 EL  261'E-&5C      EHERGE    YES                          YES              EHERGE                          EHERGENC    YES            EHERGENC      YES EE-165C 8 8XR                      8 HOLR                      8 HOLA                          8 HOLR                        8 dna    N BAT. PACK  YES                BAT. PACK                    BAT.Pox        E BAT. PACK                  BAT. PACK STANDBY        N(RHAL                                                  NORHAL                                                        NORHAL    YES              2VBB-UPSID SWITCHGEAR ROOH a) SWG. PANELS ESSENTIAL                        ESSENTIAL                    ESSENTIAL                      ESSENTIAL YES                ESSENTIAL YES (2) HCC FRONTS                                                                                        35 CONTROL BLDG. EHERGE                                                        EHERGE                          EHERGE      YES            EHERGENC      YES EL                                                                                                                                          8 261'E-65C 8 BXR                      8  HOLR                      8 N(XR    YES 8 HXR                          HOLR EE-165C            BAT. PACK                  BAT. PACK                    BAT. PACK                      BAT. PACK                    BAT.PACK NORHAL                      NORHAL                          NORHAL      NONE            NORHAL    YES              2VBB-UPSID EPICS SWITCtSEAR RQOH                                    ESSENTIAL                    ESSENTIAL                      ESSENTIAL YES                ESSENTIAL YES CONTROL BLDG.                                                                                          15                          15 EL  261'E-65C                                  EHERGENC                    EHERGE                          EHERGENC    YES            EHERGENC    YES EE-165C              8 BXR                      a  exa                      8 (XXR                          8 IRLR                        8 (K)LH BAT+ PACK                  BAT. PACK                    BAT. PACK                      BAT, PACK                    BAT.PA(X (CORRIDORS)
NORHAL                                                                                    NORHAL      YES              2VBB-UPSID STANDBY SWITCH%EAR ROOH                                    ESSENTIAL                    ESSENTIAL                      ESSENTI(V. YES              ESSENTIAL YES CONTROL        BLDL EL+ 26)'E-65C 8 NXR                      8  NQLR                      8 HRR                          8 NXR                        8 N(na    NONE EE-16SC            BAT. PACK                  BAT. PACK                    BAT. PACK                      BAT.PA(X                      BAT PACK
 
NHP2 LIGHTING STSTEH PO)fER SOURCE AND MINIHUH ILL'NfINATIONAVAILABLE                                                          PAGE HODES OF OPERATION TRANSIENT LOCA  8 SEISMIC
                                                                                                                ))ITH LOOP                  NITHOUT LOOP HIN.                          HI)L                K HIM.                                            '"LU)L                          ILLlH    HIN                  ILLUH    HI)L  ESSENTIAL PDVER            AVAIL    POVER                AVAIL  Pom      PROVIDED    AVAIL. POVER      PROVIDED AVAIL    POVER      PROV)DED  AVAIL. LIGHT1tO REMARKS SOURCES            fF DDT SOURCES              fFOOT                          fFOOT  SOURCES              fF DOT  SOURCES                lFOOT  UPS PANEL BY POVER SRSCE  C~E)              BY POVER SOLACE  CAtOLO            BY POVER Sm)RCE    CANDLE)
BY PDVER SOURCE  C~E)                BT POVER SOURCE  CANDLE)    ID.
NORHAL    199            NORHAL      IBB                                            NORHAL                                                      2VBB-UPS)0 STAHDBT S)fITCHGEAR RDOH    ESSENTIAL  YES            ESSENTIAL  YES              ESSENTIAL  NONE              ESSENTIAL  YES IEAST CABLE CHASE AREA)
COHTRCL BUXL EL &#xc3;l'E~
EE-)at)c 2VBB-UPSIC NOTE a HOUR COMHON                                                                                                                                                        2VBB-UPS10 BATTERY PACK PROVIDED It4.T OH INSIDE AREAS ISTAIR)fATS) ESSENT IIL  I99            ESSENTIAL  198                                            ESSENTIAL    IBB                          199                        SAFE SHUTOOVH PATHS.
fALL IRI)VDOS) 8 tKXA                    8 HOLA                      8 )NUR                        8 HDtA    YES 8 )K)UR BAT.PACK                  BAT+ PACK                    BAT+ pAcK                      BAT+ PACK                    BAT+ PACK NORHAL    YES                                                                        NORHAL                                                      2YBB-UPSIC HDTE 8 HOUR COHMCN                                                                                                                                                        2VBB-UPSID BATTERY PACK INSIDE AREAS                                                                                                                                                                PROV)DEO CN.T  OH fEGRESS PAT)a ESSE)fl)AL  YES            ESSENTIAL  YES                                            ESSENTIAL                                                              SAFE SHUIDOVN PATHS.
fALL NhtfltCS) 8 talA                    8 H)XA                      a tK)UR  YES 8 HOtA      YES a tK)UR BAT. PACK                  BAT. PACK                    BAT PACK                      BAT. PACK                    BAT. PACK 2VBB-UPSIC COtafDN                                                                                                                                                      2VBB-UPSID ESSENTIAL  199              ESSENTIAL  tONE              ESSENTIAL    IBB              ESSENTIAL    IBB EXIT SIGNS ESSENTIAL    199 OV.L DR IVI)OS)
 
Af'fnareevV 7                      IAAF g NMP2 LIGMTING SYSTEM POWER SOURCE AND MINIH)M ILLUMINATIONAVAILABLE                                                            PAGE M(K)ES OF OPERATION TRANSIENT LOCA  h  SEISMIC WITH LOOP                  WITHOUT LOOP MIN.              /        MIH.                X ILLUM.      Ml)L                        MIN.                2                ESSENTIAL POWER              AVAIL    POWER              AVAIL. POWER                AVAIL. POWER              AVAIL. POWER                AVA'L-    LIGHTING SOURCES            (FOOT  SOURCES PROVIDED (FOOT  Q)URCES PROVIDED (FOOT'ES          PROVIDED (FOOT  SOURCES PROVIDED (FOOT  UPS PANEL BY POWER SOURCE  CA)NLE)            BY POWER SDLRCE  C~E)              BY POWER SOURCE    CA)K)LE)            BY POWER SOURCE  CANDLE)            BY POWER SOURCE  C  NXE)      ID.
NORMAL                      NORMAL                                                      NORMAL                        2VBB-lFSlO STA)4)BY SWITCNGEAR RMM ESSEHTIAL  YES            ESSEHTIAL                    ESSEHTIAL                      ESSEHTIAL  YES            ESSENTIAL    YES (GENERAL AREAS)
(XNTROL BLD(L E(
2GI'E-65C EE-)65C 2VBB-lPSIC Ct&#xc3;NN                                                                                                                                                          2VBB-UPSID IHSIDE AREAS (STAIRWAYS) ESSENTIAL    IBQ            ESSENTIAL                    ESSENTIAL                      ESSENTIA. 188            ESSENTIAL    IBB (ALL DRAWINGS) b NOIR                      S )K)LR                    S )K)LR                        S HOLA                      S HOLA BAT+ PACK                  BAT. PACK                    BAT. PACK                      BAT PACK                    BAT PACK NORMAL    YES              NORMAL                                                      HORMAL                        2VBB-UPSIC )NTE S HOLR CROCK                                                                                                                                                        2VBB-UPSID BATTERY PACK INSIDE AREAS                                                                                                                                                                PROVIDED ONLY ON (EGRESS PATH) ESSENTIAL    YES            ESSEHTIAL  YES              ESSENTIAL                      ESSEHTIAL  YES            ESSENTIAL    YES                          SAFE SWTOOWN (ALL DRA)O(GS)                                                                                                                                                                PATHS.
b HSLR                      S HOLR                      S HOLR                          S HOLR                      S HGLR BAT, PACK                  BAT. PACK                    BAT. PACK  YES                  BATs PACK  YES            BAT. PACK 2VBB-UPSIC C&tQN                                                                                                                                                        2VBB-IfSIO IHSIDE AREAS EKIT SIGNS ESSENTIAL    IBB            ESSENTIAL                    ESSEHTIAL                      ESSENTIAL  IBB            ESSENTIAL    IBB (ALL Df(AWINGS)
 
l'll ATf4~6nlT'                        P~~ gong ISIP2 LIGHTING SYSTEM POWER SPLRCE AND MINIINM ILLUMINATIONAVAILABLE                                                      PAGE 5 MOPES OF OPERATION TRANSIENT LOCA  dc SEISMIC WITH LOOP                  WITHOUT LOOP ILLLH. MIN.                          MIN.                          MIN.                /
ILLLSL                                MIN. ESSENTIAL AVAIL    POWER                AVAIL. POWER                  AVAIL. POWER              AVAILe  POWER                AVAIL. LIGHTING SDLRCES PROVIDED BY POWER SXRCE LFppT CA)6)LE)
SOURCES PROVIDED BY POWER SOURCE LFOOT CANDLE)
SDLRCE $  BY POWER SOURCE LFOOT CAINLE)
SDLRCES pROVIDED BY POWER SOURCE (FOOT CANDLE)
SOURCES  BY ~R SOURCE (FOOT CANDLE)
UPS PAHEL 10 CLXITRPL RXN M)R)LAL                                                  2VBB-L$%$
LEAST-WEST CORRIDON  ESSENTIAL    33@                                          ESSENTIAL  NONE              ESSENTIAL                  ESSENTIAL    333 CONTROL BLDG EL. 386 EE-65E b HXR                        S HXR                        $ HXR                          S HXR                        S NXR BAT. PACK                    BAT. PACK                    BAT. PACK                      BAT PACK                    BAT. PACK VBB-iX%10 Q)RTfKAST STAIRS                                                              ESSENTIAL CONTROL BLDG. ESSENTIAL    198            ESSENTIAL    189                        NONE                                            ESSENTIAL EE-65E EE-650 EE-165C EE~        S WXR                        S BXR                        $ HXR                          b  HOLR                      S HNR BATo PACK                    BAT. PACK                    BAT. PACK                      BAT. PACK                    BAT. PACK SOUTHWEST                                                                                                                                                      2VBB-UPS10 STAIRS CMfRPL BLDG ESSDITIAL      189            ESSENTIAL    188              ESSENTIAL  NONE                                          ESSENTIAL  189 EE-66B EE-650 EE-66F EE-65C    S IXXR                      S HOLR                        S HOLA                        S HOLR                      S HOLR EE-165C                                                                          'YES BAT. PACK                    BAT. PACK                    BAT. PACK                      BAT. PACK                    BAT. PACK YES              NORHAL      YES                                            NORMAL                                                  2VBB-UPS10 INTER    BAY RA)4 ESSE NTIN. YES            ESSENTIAL    YES              ESSENTIAL    NONE              ESSENTIAL                  ESSENTIAL EL 258 Tp EL 261 EE-7%        S IKXR                      S HXR                        S INLR                        b NXR                        S HOLR BATo PACK                    BAT+ PACK                    SAT PACK                      BAT+ PACK                    BATs PACK
 
1
                                                            %%>2 I.IGHTING SYStEH POwER SOURCE ANO HINI)K)H    ILLUHINAtlONAVAILABLE                                                        PAGE 6 HOOES OF OPERATION TRANSIENT LQC4                      LOCA 5 SEISHIC WITH LQIP                      WITHOUT LOOP X IF                          X OF                          X
                      ~R        ILL)M.
PROVIDED Ht)L 4VAIL                ILLU)L PRQVIOEO    AV41    POWER HIN.
4V4IL    POWER tu~
PROV IOEO  FOOT'V4IL, PQWER
                                                                                                                                                                  % OF ILLIH.
PROV IOEO HIN.
4VAIL ESSENtIAL L[GHTINO BY POWER SOURCE
                                            )FOOT CANOLE)
BY POWER SQRCE
                                                                          <FOOT CANOLE)
SOURCES    BY POWER SOURCE
                                                                                                        <FOOT  SQRCES    BY POWER SQRCE    ~E)                    BY POWER SOURCE (FOOT CANIXE)
UPS PANE) 10.
NQRHAI. YES                                                                            NQRHAL                            NQRH41.      YES              ZVBB~IO REACTIR IXOO.
EL 353'-N'EET SSENTIAL  YES                    'ftAL YES                    N)'IAL                    ESSENTIAL    YES                  SSEN TIAL  YES J
8 HOIR                        8 NXR                          8  HOUR                        8 HQR      YES                  8 HQR BAT PACK                      BAT. PACK                      BAT PACK                      BAT PACK                          BAT PACK NORHAL      YES                                              NORHAL                        NQRHAL                            NORHAL      YES              ZYBB~IC REACTOR KOG.
AUX 84YS NQ)TH            SSENTIAL  YES                  NTIAL YES                  SSENTIAL                      ESSENTIAL    YES                  SSENTIAL    YES EL 215'~
EE&TL 8 NXR                        8 HOUR                        8  HOUR                        8 HQR      YES                  8 HQR BAT. PACK                      BAT. PACK                      BAT. PACK                      BAT. PACK                        BAT. PACK REACfOR M)O.
NQRHAL    YES                                              NORHAI                        NORMAL                            NORHAI      YES              ZVBB~IO AUX BAYS SQ))H                TIAL  YES                    'IIAL YES                    ENT IAL                      SEN'flAL  YES                  SSENTIAL    YES EL 2)5'448'-
EE&7L 8 HQ)R                        8 NOIR                        8 HQ)R      YES 8 HQR YES 8 NQR BAT. PACK                      BAT. PAOC                      BAT. PACK                      BA'f. PACK                        BAT. PACK NQRHAL      YES                NQRHAL      YES              NOR MAL                        NQRHAL                            NORHAL      YES              ZVBB~IO AUX SERVICE BLOG. SOUTH EL    261'E&7P SSENTIAL  YES                    TIAL  YES                                                SENrtAL    YES                  SSEN)'IAL  YES 8 NXR                        8 NXR                          8 HQR                          8 HQR                            8 HQR ltAT PACK                      BAT. PACK                      BAT. PACK                      84T. PACK    YES                  BAT. PACK HORHAL      YES                                                                                                                NQRHAL      YES              2VBB-UPSIC SCREENWEIL SLOG.
EL    261'E-728 SSENTW. YES                      TIAL YES                      fIAL                      SENT IAL  YES                  SSEN'ftA). YES
                        ~
8 )KXR                        8 HQR                          8  HOUR
                                                                                              'YES              8 NXR      YES 8 HQR BAT. PACK                      BAT. PACK                      BAY.) AC                      84T. PACK                        BAT PACK LGHTIl4 IN REACTOR BUILOING IS POWEREO FR(H PLANT EHERGENCT POWER OISTRIBUTIQI STSTEH. OURING LOC4, 'fHIS NQI-IE LIGHttNG SYSTEH POwER IS TRIPPEO BY AN  ACCIENt SIGNAL
 
J8%'2 LIGHTING SYSTEM POVER SOURCE ANO MINI %H tLLUHINAI'ION AVAILABLE                                                              PAGE  7 HQQES QF 6%JIATION TRANS IEN T LOCA  8 SEISHIC                'VITH LOOP                  VITHIXJT LOOP 8 OF                                8    OF HIIL                7 OF                                    HIIL TLLI84. HIM.
AVAIL HIJL AVA~    POVER ILL~    AVAIL  POVER ILLUH. HBL AV40    POVER                  AVAIL.
ESSENTIAL LIGHTING PRQVIOEQ                                                        PROV!OED                                                        REMARKS SIXRCES    BT  neCR  IFOOT              BY POVER        IFOOT  SmRCES    BY POVER    (FOOT SIXRCES    BY POVER                      BY POVER    IFOOT  UPS  PAWL SCXJRCE  CAHJLEJ              MIRCE                              SOURCE                        SOURCE  CANm.E)              SOURCE    CANQLEI    IL TIR BLDG.
HJRHAL      YES            NORHAL      Nt&                    NORHAI.                                                  NORHAL          YFS            2VBB~IC Et        2I5 EEOC                S%NTIAL      YES            SSEMTIAL          'IES              SSEMTIAL                    ESSENTIAL                    ESSEM'f IAL    YES SPENT          RKL      8 NXR                        8 HXR      YES 8 HXR      YES              8 NXR        YES            8 NOIR CQm.DKI              BAT, PACK                    BAT, PACK                          BAT, PACK                    BAT, PACK                    BAT. PACK AREA NORMAL      YES            NORHAL                                                                                                        YES HOKED VBB~SIC TOR BLDG.
EL. 2<8        M        %7ITIAL    YES            ESSENTIAL            YES                                          SSEMTIM. YES              SSEMTIAL      TES EE+7D 8 HXJR                        8 HXIR                              8 NXR        YES 8 NXR        YES 8 HXR YES
                    , BAT. PAI7(                  BAT, PACK                            BAT, PACK                    BAT, PACK                    BAT. PACK NORHAL      YES            NORHAL                                                            HORHAL                        HJRHAL      YES              2VBB~SIC  ACCESS P4TH t74.Y NO%'TIAL SIJITIAL    YES                                  'YES                                        SSEMTIAL      YES            SSDITIAL    YES 8 HXJR                        8 HXR                              8 NXR                        8 NXR        YES 8 MmR BATe PACK                    BAT, PACK              YES          BAT PACK    YES            BAT, PACK                    BAT, PACK QRHAL        YES                                                                              MORHAL                        HJRHAL        YES            2VBB-ITIC SDITIAL    YES                              YES                                            SSEMTIM.      YES            $ %MTIAL      YES 8 HXR                        8 HXR              YES 8 NXR        YES 8 NXR        YES 8 IKXR BAT, PACK                    BAT. I ACK                          BAT, PACK                    BAT PACK                    BAT, PACK WeeL        YES                                                  NDIHAL                                                    NORMAL      YES              2VBB-IPSIQ TOR BLQd.
SEJITIAL    YES            ESSOITI            YES                SSEMTW.                    ESSENTIAL      YES            SSBITIAL    'YES Et  328'-l8'%7M 8 HXR                        8 HXR              YES              8 HXR        YES            8 NOIR        YES            8 NXR Bar. I ACX                    BAT. PACK                          BAT. PACK                    BAT. PACK                    BAT. PACK i NIXBIAL LIGHTING IM REACTOR BUILDING IS POVERED FROM            PLANT EHERGEMCY PQVER OISTRIIXJTION SYSTEH. OIRIMG LOCA, THIS NON-IE LIGHTII4) SYSTEH PQVER IS TRIPPEO BZ AN ACCIDEMI'IGNAL~
 
avTmH>~f 7                        pres g'+
                                                    %(PZ LIGHTING SYSTEH POwER SOURCE ANO HINIHUH ILLUHINATIQNAVAILABLE                                                      PAGE  8 HOOES OF OPERATION TRANSIENT LOCA  8 SEISMIC WITH  LRP                  WITHOUT LOQP HIN.                ILL~      HIM.              I LUH      HIN,              ILLUH. HIN.                ILLUIL  HIN. ESSENTtAL
(~T ~ER 4V4ll                                                      4"4'"-
POWER    PROV IOED BY PQWER (FOOT C(WE)LE)
POWER SOURCES    BY POWER AvAIL.
(FOOT POWER SOURCES PROVIOEO 8'I POWER
                                                                                              ~E)
(FOOT POWER SOURCES PROvtOEO Y POWER AVAIL C~E)
PROvtOEO BY POWER 4V4IL (FOOT CAIZILEI UPS  P~
LIGHTINO
[O.
REHARKS S(X)RCE                      S(mRCE                      SOURCE                        SOURCE                        SQLIICE ACT6I BLOC.                                                                                                                                                      ZVBB ~LB ST4IRS EE-67E EE-67F        SDITIAL IBB                  SENT IAL  188                                                                                    te8 E'E-67O EE%7H EEWTJ 8 )CUR                        8 HOUR YESi              8 IXXXI                      8 IKXXI                      8 H(XXI BAT, PACK                      BAT, PACK                    BAT, PACK                    BAT PACK                    BATe PACK T& BLOC.                                                                                                                                                        ZVBB~LC AUX. BAYS N(XITH            TIAL  IBB                                              SENTIA(.                                                SSENTI4L ST4IRS EE<7L 8 HER                          8 Ie)R    YES0              8 IKNXI                      8 IXXXI                      8 H(X)R BAT, PACK                      9AT. PAO(                    BAT, PACK                    BAT PACK                    BAT, PACK ACTUI BLOG.                                                                                                                                                      ZVBB-UPSLO AUX. BAYS SOUTH ST4IRS        SENT IAL  IBB              ESSENTIAL                                                            IBB EE.67L 8 IOLXI                        8 HOUR    YES'                IKWXI YES              8 IKX)R                      8 IKXXI 84T, PACK                      BAT+ PAO(                    BAT PACK                    BAT, PACK                    BAT+ PACK HORHAL LIGHTING IN REACTOR BUILOING IS POWERED FROM PLANT EHERGENCY POWER DISTRIBUTION SYSTEH. IXNING LOCA. THIS NON-IE LIGHTING SYSTEH POVER IS TRIPPEO BY AH ACCIDENT SIGNAL.
 
NMP2 LIGHTING SYSTEH POWER SOURCE AND MIHINJM ILLUMINATIONAVAILABLE                                                          PAGE MODES OF DPERATIDN TRANSIENT LOCA  4 SEISHIC WITH LOOP                  WITHOUT LOOP X
ILLL&#xc3;. MIN.                  I ILL      MIH.                                                OF                          X OF ESSENTIAL POWER PROVIDED  AVAIL. POWER                AVAIL. POWER                AVAIL. POWER                      POWER ILLU)L  AVAIL. LIGHTING SOURCES                                  PROVIDED                                                    PROVIOEO                      pRovloEo BY POWER  (FOOT    SOURCES                IFOOT  SOURCES                IFOOT  SOURCES            (FOOT  SOURCES                (FOOT O'S PANEL BY POWER SOLRCE  CA)K)LE)
SDLRCE  CANDLE)
BY POWER SOURCE    C~E)              BY POWER SOURCE  C~E)                BY POWER SOURCE  C~E)        ID.
TLRB. BLDG.                                            NORMAL      YES                HORMAL    NONE                NORMAL                                  YES              2VBB-LPS1D SAFE S)IJTDOWN GRMM) FLOOR                                                                                                                                                                                PATH O)l.Y No CORfODOR                                                                                                                                                                                ELXJIPPKNT ELe                      ESSEHTIAL                  ESSEHTIAL    YES              ESSENTIAL  NONE              ESSENTIAL  YES              ESSENTIAL    YES 258'E-66B 8 NXR                        8  HLXR                        8 HOLA                        8 NXR                      8 HOLR BAT+ PACK                  BAT+ PACK                      BATs PACK  YES                BAT+ PACK  YES              BATe PACK TURL BLDL                  NORMAL                      NORMAL      YES              NORHAL      NONE              NORMAL                      NORMAL      YES              2VBB-UPSIO SAFE SHUTDOWN CLEAN ACCESS AREA                                                                                                                                                                      2VBB-UPSIC PATH D)LY NO ESSENTIAL EOUIPMENT EL. 2QY                                              ESSENTIAL    YES              ESSENTIAL  NONE              ESSENTIAL                  ESSENTIAL    YES EL              2Q'L.
288'-8'L.
396'E-66H 8 )KXR                      8  HL)LR                      S HXR                          S )NLR                      S HOLR BAT. PACK                  BAT. PACK                      BAT PACK    YES                BAT. PACK  YES              BAT. PACK TtSL BLOL                                                                                                                                                                      2VBB-UPSIC SAFE SWTDOWN CLEAN ACCESS                                                                                                                                                                              PATH M.Y ND AREA                                                                                                                                                                                  EIXJIPPKNT STAIRS                                              ESSEHTI)V. YES              ESSENTIAL  NONE                                          ESSENTIAL    YES EL+          258'L 2Q'L 288'-8'L 386'E-66H b HOLR                      8  HOLR                        8 HXR                          S HOLR                      8  HOLR BATo PACK                  BAT. PACK                      BAT PACK                      BATo PACK                  BAT. PACK
 
IU ACCESS ROUTE TAKEN BY OPERATOR FROM CONTROL ROOM TO UPS ROOM IN NORMAL SWITCHGEAR BUILDING ON 8-13-91 The  following route was taken by operator from control  room  to go to UPS room in switchgear building to transfer    alternate  power source to UPS units
    ,Operator left the control room EL 306 through south door and proceeded to west. Then he turned north along the corridor on the westside of the control room. Then he exited the control room building through north west door EL 306 to Auxiliary building. He then took the stairway just south of the elevator to go to EL 261. Then and  at EL 261 of Auxiliary building, he proceeded to south entered the corridor ( Electrical equipment Tunnel). From the corridor he entered the normal switchgear building EL 261 and proceeded to stairway located in the center of the building (West half) down to EL 237 where the UPS units 2VBB-UPS1A, 1B, 1C and 1D are located. He then transferred the UPS power to maintenance power source.
After restoring power to the above UPS units, the operator proceeded to UPS 2VBB-UPS1G via the door on the east end of the room, went south down the hall, through the door on his left (eastside) and entered the control building. He then took the stairs down to EL 214 where UPS 2VBB-UPS1G is located and transferred the power to the maintenance power.
 
CONDENSATE/FEEOMATER SIMPLIFIED SKETCH FEEOvATER COMlROL LOO)C I              )        I I                        I
                                                                                  )        I I                        I PRESS)I)RED lCQOCM    JEANS                                                LVIB              REAC)TX)
FEll4                                                    FL                VESSEL I                                    O'RVI I                    I I                    I I                    I I    QlZEMSATE      I BOOSTER      I I                                FVg I                    I    I I              I    i FVRi    )    FOI)MFlO PAWL C(&#xc3;H6ATE PAP  HIM. FLOM  IEgKR ICQI+QN COMPENSATE )MISTER PNTP HDL FLOM TEAOER FEEOPUH'lM. FLOV    TRACER FOXBORO PANEL                                        TYPICAL TRAIN A, 8,8, C TRAIN A    - 2CEC-PNL825                            CROSSOVER HEADERS BETWEEN TRAINS TRAIN B      - 2CEC-PNL826                          (PROVIDE  CROSSOVER FLOW TRAIN C      - 2CEC-PNL827 FEEDWATER CONTROL PANEL 2CEC-PNL6I2
 
Oe A, T rAQf tttl +II          '/
fPRO Pomr Generation Services Department General Electric Company Q
GE Industrial a power  Systems 3532 James St.. PO. Bott 484t, Syraorse. Ny t322t NIAGARA MOHAWK POWER CORPORATION              cc:          NIAGARA MOHAWK POWER CORP.
NINE MILE POINT NUCLEAR STATION UNIT g2r  GENERATOR g180X632                              R. Abbott GENERATOR INSPECTION  POSSIBLE                            N. Kabarwal PHASE-TO-PHASE FAULT                                        M. McCormick GENERAL ELECTRIC COMPANY L. Jordan                (37-3)
August 28, 1991                                              W. Judd S. Kolb R. Smith W. Turk Mr. Anil K. Julka NIAGARA MOHAWK POWER CORPORATION 301 Plainfield Road North Syracuse,  New York  13212
 
==Dear Mr. Julka:==
 
Due  to the August 13, 1991 failure of the phase B step-up transformer on Nine Mile Point Unit g2, General Electric Generator Engineering recommends performing a thorough visual inspection of the generator stator end winding support system at the next convenient opportunity.
The inspection should include    all  accessible components of the stator end winding support system, including stator bar end arms, blocks, ties nose rings, and outer axial supports.                    This inspection should be accomplished    by a  GE  Generator Specialist trained to detect the potentially subtle indications of    damage.
The above recommendation is based upon the possibility of phase-to-phase generator short circuit currents through the failed transformer as high as 5pu. The          initial              recommendation for the immediate generator inspection considered the possibility of higher currents, resulting in several times greater end winding forces.
Physical evidence of high current forces at the transformer .low side was the primary driver for this recommendation, since measurements of generator currents were not available.                Our engineers continued to review the limited data available and subsequently concluded that currents high enough to do probable damage to the generator were not likely. This conclusion was reached primarily by considering a measurement of depressed generator voltage during the incident, inferring generator currents, and specific capabilities of the generator design.
 
'k Page  II Mr., Anil K. Julka August 28, 1991 Should you have any questions regarding this recommendation, please contact  me.
Very    ruly yours J  eph  . Kir ch Ma  ager Engine  ring Services Pow r Generatio    Services "SYRACUSE OFFICE JAK/bs JAK-059
 
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Revision as of 12:15, 13 November 2024

FOIA-2023-000163 - Responsive Record - Public ADAMS Document Report. Part 11 of 19
ML23251A029
Person / Time
Issue date: 08/31/2023
From:
NRC/OCIO
To:
- No Known Affiliation
Shared Package
ML23251A034 List:
References
FOIA-2023-000163
Download: ML23251A029 (1)
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