ML19309C545
| ML19309C545 | |
| Person / Time | |
|---|---|
| Site: | Three Mile Island  |
| Issue date: | 05/01/1967 |
| From: | JERSEY CENTRAL POWER & LIGHT CO., METROPOLITAN EDISON CO. |
| To: | |
| References | |
| NUDOCS 8004080740 | |
| Download: ML19309C545 (13) | |
Text
__ _
TABLE OF CONTENTS Section P_ge 8 ELECTRICAL SYSTD4S 8-1 8.1 DESIGN BASES 8-1 8.2 ELECTRICAL SYSTEM DESIGN, 6-1 8.2.1 NETWORK INTERCCNNECTIONS 8-1 8.2.1.1 Single Line Diasram 8-1 8.2.1.2 Reliability considerations 8-1 8.2.2 STATION DISTRIBUTION SYSTEM 8-2 8.2.2.1 Single Line Diagram 8-2 8.2.2.2 Auxiliary Transfemers L2 1
8.2.2.3 6900 Volt Auxiliary System 8-2 8.2.2.h kl60 Volt Auxiliary System 8-3 I 8.2.2 5 h80 Volt Auxiliary System 8-3 8.2.2.6 250/125 volt D-C System 8-h ;
8.2.2.7 120 Volt A-C Vital Power System 8k 8.2.2.8 120 Volt A-C Regulated Power System 8-k 8.2.2 9 120Y208 Volt A-C Power System 8k 8.2.2.10 Evaluation of the Physical Layout, Electrical Distribution System Equipment 8k 8.2.3 SOURCES OF AUXILU.".Y PCWER 8-3 8.2.3.1 Description of Power Sources '5 d.2.3.2 Power to Vital Leads and Load Shedding 8-8 8.2.3.3 Reliability Condiderations 8-8 8.3 TESTS AND INSPECTICNS 8-8 0 8 o o4 o so 79'o l 8-1 (Revised 12-22
LIST OF FIGURES Figure No. Title 8-1 Electrical Pcver Syste=s - Single Line Diagra=
8-2 Site Trans=ission Itap O
l l
O 000 l- Iq 3-11
8 ELEC"'RICAL SYSTEMS O 8.1 RESIGN 3ASES The design of the electrical syste=s for this nuclear station is based en providing the required electrical equipment and pcver sources to insure centinuous creration of the essentic.1 staticn auxiliary equipment under an conditiens.
8.2 ELECTRICAL SYSTE4 CESIGN 8.2.1 NETWOPI IU"'IRCONNECTIONS The unit win generate electric pcver at 19 kv which vill be fed through l l an isolated phase bus to the unit =ain transfor=er where it vill be l stepped up to 230 kv transmission voltage and delivered to the substatica. 1 The substation design vill incorporate a breaker-and-a-half scheme for high reliability and vin be cennected to the existing Metropolitan Edison Ccmpany 230 kv transmissica netverk by three circuits , two fun capacity circuits going north to Middletevn Junctica en separate double-circuit towers and one south to Jackson en single circuit tevers. Middletevn Junction, located 15 =iles frem Three Mile Island, is a major substation in the Pennsylvania-New Jersey-Maryland Intereennection with 230 kv trans-mission line connections north to Hummelstevn, east to South Reading, and south to 3 runner Island, a 1,500 MW generating station evned and operated by the Pennsylvania Pcver & Light Company.
8.2.1.1 Single Line Diagram Figure 8-1 includes a single line diagram of the substation electrical system.
8.2.1.2 Reliability Consideratiens Reliability censiderations to minimize Lie probability of pover failure due to faults in the network intercennections and the associated switch-ing are as follevs :
- a. The two Middletevn Junction circuits vill each be capable of carrying full unit output and vill be instaned on different double circuit towers, separated by a safe distance.
- b. The line to Jackson vill be capable of carrying 50". of fun unit output and win follev an erSirely different route than the lines to Middletevn Junction,
- c. Middletcun Junction substation is only 15 miles away, thus reducing line expcsure.
- d. The breaker and a half svitching arrangement in the 230 kv substation vin include two fun capacity main busses. Pri-mary and backup relaying vin be provided for each circuit O' along with circuit breaker failure backup switching. These provisions vin pe: nit. the folleving:
- 1. Any circuit can be switched under ner=al or fault switch-
, , ing withcut affecting another circuit.
8-1 (Revised 10-2-67)
- 2. Any single circuit breaker can te isolated for maintenance without interrupting the pcver or protectica to any circuit.
- 3. Short circuit of a single =ain bus vin be isolated without interrupting service to any outgoing line er to the plant.
- h. Short circuit failure of the tie breaker vill result in the loss of its two adjacent circuits until it is isolated by discennect switches.
5 Short circuit failure of a bus side breaker vill result in the loss of one circuit and one auxiliary transfomer until it is isolated.
- 6. Circuit protection vill be insured fre= failure of the p'rimary protective relaying by backup relaying.
With the above protective features, the' probability of loss of =cre than ene source of 230 kv power frem faults is low; however, in the event of an cecurrence causing 1 css of up to an the 230 kv remote connections, the engineered safeguards will be supplied frem one or = ore of the remaining sources of power (Refer to 8.2.3).
8.2.2 STATION DISTRI3UTION SYSTEM The station distribution system vin censist of the various auxiliar/
electrical systems designed to provide reliable electrical power during an modes of station operation and shutdown conditions. The systems g vill be designed with sufficient pour sources, redundant busses , and /
required switching to acecmplish this. Engineered safeguards auxiliaries vill be arranged so that icss of a single bus for any reason vin still l leave sufficient auxiliaries to safely perform the required functions.
j In general, the auxiliaries related to functions other than engineered
) safeguards vill be connected to any of the three unit auxiliar/ busses.
l Engineered safeguards loads vill be divided between the two engineered l
safeguards buses in observance of the single failure criterion.
l 8.2.2.1 Single Line Diarras Figure 8-1 is a single line diagram of the station distribution system.
1
! 8.2.2.2 Auxiliar/ Transfor=ers Two full size auxiliary transfer =ers vill be installed with this unit.
The two transfomers vill be connected to different 230 kv busses and vill provide a source of pcVer for startup, shutdovu, and after shutdown requirements. Either of the two transfomers vill also serve as a ecm-plete stand-by source in the event of cne auxiliary transfomer failure.
Each of the aforementioned transfomers will have tvo isolated seconda$r/
vindings, cne at 6900 volts and one at kl60 volts for the purposes outlined in the folleving paragraphs.
8.2.2.3 6900 Volt Auxiliary Syste=
The 6900 volt auxiliary system vin be designed solely for the 9000 horse-
, power reactor ecolant pump setors. This system vill be arranged into two j
, 6-2 (Fevised 12-22-67)
bus secticas , each feeding two =otors. During nomal operation cce bus will be fed frem each auxiliary transfomer, although either transfor=er vill be espable of feeding both busses and autcmatic transfer vill take place in vither directien, by relay actica, if a voltage failure should occur. Lor =al bus transfers initiated at the discretien of the operator for test or maintenance purposes vill be " live bus" transfers ; i.e. ,
the io.:cming source feeder circuit breaker vill be closed onto the runn'.ng bus section and its interlocks vill trip the cutgoing source fer.ier circuit breaker which vill result in transfers without power interruption. Manual pralleling of sources which are out of phase vill be prevented by the use of synchronism check relays. Emergency transfers wh'ch result upon less of nomal unit sources vill be rapid bus transfers i 1.e. , the outgoing source feeder circuit breaker vill be tripped and its interlocks vill close the inecning source feeder circuit breaker which vill result in a transfer within six cycles.
8.2.2.h h160 Volt Auxiliary System The kl60 volt auxiliar/ syste= vill be arranged into five bus sections, three for all nor=al auxiliaries and two for the engineered safe-guards. As in the case of the 6900 volt auxiliary system, during nomal cperation, approximately half of the h160 volt load vill be carried on each of the two auxiliary transfomers; i.e. , busses #1A, #13 and #1D
=ay be carried by one transfor=er and busses #1C and #1E may be carried by the other transfor=er. Manual transfers using synchronism check relays and automatic fast emergency transfers vill be as described for the 6900 volt system in section 8.2.2.3, except that the engineered safeguards busses vill have, in addition to nomal transfor=er sources ,
a feed frem two diesel-engine generator sources. Each of the auxiliary diesel generators will be capable of carrying the required engineered safeguards load. Upon failure of the nomal source for an engineered safeguards bus, the associated diesel-generator vill autcmatically str.rt and pick up its associated bus.
8.2.2 5 k80 Volt Auxiliary System The L80 volt auxiliary system vill be arranged into six separate bus sections. Each bus section vill be fed frem a separate load center transfomer which vill be connected to one of the five h160 volt bus sectices. Varicus 480 volt motor control centers will be located throaghout the statica to supply pcver to equipment within the related area. Each motor control center vill be separately fed frem the k80 volt auxiliary system. Connections and switching vill be arranged to prevent less of =cre than ene centr:1 center frem which engineered safeguards auxiliaries vill be fed and redundant auxiliaries feeders arranged so that such less will still leave an adequate number opera-tienal.
Mi"f~ 0001 145 8-3 (Revised 12-22-67)
8.2.2.6 250/125 Volt D-C System The 250/125 volt d-c system win be designed to provide a source of reliable continuous pcver for d-c pu=p matcrs, centrol, and instra=enta-tion. In general, d-c =cters will be rated 250 volts and control circuits vill be fed 125 volts d-e.
The 250/125 volt d-c system vill censist of two isolated bus secticas, each supplied by a battery and battery chargers. Tie circuits will be provided to permit one batter / to back up the other. A spare 125 volt d-c battery charger vill be provided for each batter / for backup.
8.2.2.7 120 Volt A-C Vital Pcver System The 120 volt a-c vital pcver system win be designed to provide a reliable scurce for essential pcVer, instru=entation, and centrol loads under all operating conditions. The system vin consist of fcur bus sections , each supplied frem a static inverter. Tie circuits will be provided to the 120 volt a-c regulated power system described in 8.2.2.8 for backup power. The static invertert vill be supplied nor=any frem the h80 volt a-c system through rectifiers or battery chargers with an unin-terrupted transfer to a 125 volt battery source en less of the nomal supply.
8.2.2.8 120 Volt A-C Regulated Pcver System l .
l A 120 volt a-c regulated power system vill be provided to supply instru-I mentation, centrol, and power loads requiring regulated 120 volts a-c power. It vill censist of distribution panels and regulating transformers g fed frem =oter control centers.
8.2.2 9 120Y208 Volt A-C Power System A lov voltage 120Y208 volt a-c pcver system vill be provided to supply i instrumentation, control, and pcuer loads requiring unregulated 120Y208 volts a-c power. It vill consist of distribution panels and transformers fed frem motor control centers.
8.2.2.10 Evaluation of the Physical Layout, Electrical Distribution System Eauirment The physical locations of electrical distribution system equip =ent vill be such as to minimize vulnerability of vital circuits to physical damage as a result of accidents. The preposed locations are as follevs :
- a. The two full sized auxiliary transformers vill be located cut of doors , physically separated from each other. Light-ning arresters vill be used where applicable for lightning protection. All transfor=ers vin be covered by autcmatic water spray systems to extinguish oil fires quickly and pre-vent the spread of fire. Transfo=ers vill be well spaced to minimize their exposure to fire, water, and =echanical damage.
- b. The unit auxiliary c900 volt switchgear, bl60 volt switch-gear, and Lc0 volt switchgear vill be located in areas so as to f i' I i'i' #
8 h (Revised 12-22-67)
minimize exposure to =echanical, fire, and water dama6e. This O a ia= == 111 * >r=> r1r ecere1= tee 1 etric 117 '= > r it safe operation of the equipment under normal and short circuit conditions.
- c. The engineered safeguards h160 volt switchgear and h80' volt load centers vill be physically separated frcm each other and frcm the unit auxiliary switchgear so as to further minimize exposure to mechanical, fire, and water damage. This equipnent vill be coordinated electrically to permit safe operation under no: mal and short circuit conditions.
- d. k80 volt motor control centers vill be located in the areas of electrical lead concentration. These associated with the turbine-generator auxiliary system in general vill be located belev the turbine-generator operating f1cer level. Those associated with the nuclear steam supply system vill be located in the Auxilia:7 Building. Motor control centers vill be located in areas so as to =inimize their exposure to mechanical, fire, and water damage.
- e. The station batteries and associated chargers and inverters vill be in separate rocms and in a Class I structure to minimize vulnerability to dama6e frem any source.
- f. Within practical limits , nonsegregated, metal-enciesed h160 CJ blocks of current are to be carried. The routing of this metal-enciesed bus vill be such as to minimize its exposure to mechanical, fire, and water damage.
g.
The application and routin6 of control, instrumentation, and power cables will be such as to minimize their vulnerability to dama6e frem any source. All cables vill be applied using conservative =argins with respect to their current carrying capacities , insulation properties , and mechanical construction.
Cable insulations in the Reactor Building vill be selected so as to minimize the harmful effects of radiation, heat, and humidity. Appropriate instrumentation cables vill be shielded to minimize induced volta 6e and magnetic interference. Wire and cables related to engineered safeguard and reactor pro-tective systems vill be routed and installed in such manner as to maintain the integrity of their respective redundant channels and protect them frem physical damage.
8.2.3 SOURCES OF AUXILIARY F0WER 8.2.3.1 Descrirtion of Pever scuree_s_
l Each auxiliary power source vill have var ous l degrees of redundancy and reliability as outlined below,
- a. As described in 8.2.2.2, normal pcver supply to unit aux 111aty loads vill be provided through either ene of the 8-5 (Revised 12-22-67)
auxiliary transfor=ers connected to the 230 kv substation busses . Power to these transfor=ers can be provided from any cne of four sources.
These include three transmission circuits and the nuclear generating unit if operating. Each auxiliary transfomer will be sized to carry the unit full load auxiliaries and the engineered safeguards auxiliaries.
- b. Upon separation of the 230 kv. substation frem the rest of the 230 kv system with no in-plant emergeney, neither the reactor nor the turbine vill be tripped. Load vi.11 be abruptly reduced to the unit auxiliary demand and the unit vill be continued in service. Autcmatic provisiens for abrupt loss of lead are covered in section 7.2.3.k. The auxiliary transfomers vill thus serve as a source of power except when:
- 1. There is a 230 kv system separaticn and the nuclear generating unit is not running.
- 2. A catastrophic vreck destroys both busses in the substation.
- 3. Both auxiliary transfor=ers fail.
DELETED
- d. Upon loss of the sources of pcuer described in (a) and (b) above, power vill be supplied frcm two autceatic, fast start-up diesel engine generators. These are sised so that either one can carry the required engineered safeguards load.
A preliminary estimate of the rating of each emergency genera-ter is 2850 kv.
l Each emergency generator vill feed ene of the engineered safe-guards h160 volt busses. The units are to be located in an annex en the opposite side of the buildi:6 frem the 230 kv l substation and transformers , and vill be separately enclosed
! to mini =1:e the likelihood of mechanical, fire, or water l damage.
Sufficient :tel vill be stored to allow cne unit to operate at full pcVer fur seven days. Fuel storage at the units l vill be sufficient for one to three hours full load opera- g I
tion. Level in the tanks vill be autceatically maintained; hcVever, frem the main storage tank using a matcr driven pump with each unit.
t
\4 i bs'.! 0001 1.48 8-6 (Revised 12-22-67)
m Each diesel-engine is to be started upon the occurrence of the '
following incidents:
- 1. Initiatien of safety injection operation.
- 2. Overpressure in the reactor building.
3 Less of voltage on the kl60 volt engineered safeguards bus with which the emergency generator is associated.
In addition, upon loss of the hic 0 volt bus voltage, the diesel-generato~r unit will be autcmatically con-nected to its bus. The sequence to acec=plish this folleving the starting signal vill be as follows:
Step 1 Autcmatic tripping of all breakers on the bus.
Step 2 After the unit ec=es up to speed and voltage.
the emergency generator breaker vill auto-matica11y close.
Step 3 Manual starting of equipment as required for safe plant operation.
'2 DELETED If there is a requirement for safeguard system operation coincident with the loss of voltage on the kl60 volt bus, step 2 vill be automatically followed by the sequential starting of safeguards equipment.
In the event one emergency generator does not come on the 2 line, the automatic starting sequence of components associated with this generator and bus vill be blocked to prevent over-loading the remaining power supplies.
The sequential leading of each diesel-engine generator with safeguard auxiliaries vill be accomplished in as short a time as possible by means of a high speed excitation system. Loads vill be added in blocks insofar as the diesel-engine generator !
is capable of accepting them. Timers will be used to (1) prevent a race with the next auxiliary in the chain and, (2) l to initiate tripping of a ecmponent which fails to start and l the starting of the next component, thereby preventing the sequence from hanging up.
I l
1 O
0001 149 O, i'I c-7 (?!evised 12-22-c7)
DELETED h Starting of a diesel-engine generator vin take 7-1/2 to 10 seconds , depending upon the =anufacturer. Frem a dead start, the high pressure and low pressure injectics systems vin be in operation within 25 seconds.
S.2.3.2 Power to Vital Leads and Lead Shedding All of the power sources vill supply pcver to the bl60 volt bus sections which serve the engineered safeguards auxiliaries and reactor protective systems. The engineered safeguard auxiliaries and reactor protective syste=s vill be arranged so that a failure of any single bus section vill not prevent the respective systems from fulfilling their protective func-tions. On loss of its nomal source of power, i.e. voltage failure, the associated safeguards bus vill be cleared of all auxiliaries and ties and the corresponding diesel-generator vin be started, brought up to speed and voltage and tied to the bus auto =stically. In the absence of safety injection or reactor building depressurizing requirements, only selected h80 volt auxiliaries will autcmatically start. Logic and control circuitry will be fed without interruption from d-c sources and inverter buses.
Engineered safeguards buses vill cnly be tied together nanually. During both nomal and emergency modes of operatien these buses vill nomally be fed frem different transfomers or diesel-generators.
8.2.3.3 Reliability consideratiens Upon a total system blackout, there vill be two remaining pcuer sources ,
i.e. , the unit and the diesel-engine generators. The coincident failure of all remaining power sources and a system blackout is incredible.
Ecvever, should this occur safe shutdevn ecoling without electric power vill be acecmplished as described in lb.l.2.8.3.
8.3 TESTS AND INSPECTIONS Control of the diesel-engine generators vill be provided en a panel located in the control roczn. Provisions vill be made in the control panel to
- =anuany initiate a fast start of any of the generators with closure of l the associated air circuit breakers connecting the generator to the h160 l volt engineered safeguards auxiliary busses. Testing of this system may l
be done by the centrol rocm operator at his convenience any time the units are tot othervise running.
The 230 kv circuit breakers vin be inspected, =aintained, and tested as l fonovs :
l l
- a. 230 kv transmission line circuit breakers vill be tested on a routine basis. This can be accceplished on the breaker and a g half scheme without removing the transmission lino frem service.
9 j. i 'I;,';6 8-8 (Revised 12-22-67)
[
i l
i I
- b. 230 kv generator circuit breakers can be tested with the gene-rator in service.
Transmission line protective relaying vill be tested on a routine basis.
Generatar protective relaying vill be tested when the generator is off-line. The hlc0 volt circuit breakers , motor starters , and associated equipment vill be tested in service by cpening and clesing the circuit breakers or starters so as not to interfere with operation of the station.
Emergency t'ransfers to the various e=ergency pcver scurces vill be tested on a routine basis to prove the operaticnal ability of these systems.
The ungrounded d-c system vill have detectors to indicate when there is a ground existing on any leg of the system. A ground en ene leg of the d-c system vill not cause any equip =ent to malfunction. 2 Grounds vill be located'by a logical isolation of individual circuits connected to the faulted system, while taking the necessary precautions to maintain the integrity of the vital bus supplies.
Motor operated valves will be tested in service so as not to interfere with the operation of the statien. Motor operated isolating valves vill be tested when the unit is off-line.
O O
O 0001 151 3-9 (Revised 10-2-ci)
7 23
_ .:Jh n.,
.n o-
- ,tl&- :: ri 0 <2 r
c[ .; :: 0 i.
'pli N.rfid~
i 4 ?
si
- i:jD : a p iE 1C J.3)si ., 1 ! EE 9 'I-in;i i
' y [ s <
' lf !:
,e 5"I$!
e1 l : !. Ei , v l ., -
5 s:
,I I ? 4L 1. E
&n 2y, j, i
j, ~ .'} l 3!
1 1 1! 1
, ! _ il'- -g_ *% '
a 2 :
l ! 4
.-.5.--,. }I'l it, al I 1;
-o.-;
- 4 c 1. .
-ll 2I !: ,
I
} .[< !IIE)I j j ~ii' ,
i l1 !
j.
e pm i: ,i x
l} II I8 is
'i
'h!
3
! "- ,-ig L L; ~1-]d 1) ! '.,- 2 i ti! i 'e' 4
- ll I d,
,3 lj li l i i
}II il!;
p . .11 i,:
'r - 6 :-.-:
l;-~-.U q I,t
- - lllii l i ! 3 H .
!! i l 7
, 1 I Jl!
l' 1 I u
- - 1; }
}
1;.
'- c- } f j
- > ;l jj } E}l I w "L i l- = g l b l -e- .c +
! i
--c--
gjjj,1L+j .L f) l jl. 1; i , 1
-:: s a,h.
.-.L -c- -
4 _L
- i i
f !
,i i lli l -W'
. < get.
j)J j 3 i I J 1 p i l ll s' j I l j i i ! > f,
+ . + . + < )$
l I J, & f ( j'.I A i l
. i, e J j .
"I i fil i 3
l! i l ! lL c--c - pLJ 4- . s- . + , i 1 i vsp liii _ % : '; pis i i
! a u i >
'< . o ; l} 2 i
- t }
Ij' I - !- ji! I
, !. .!! 3 i n 1 j
-C- : ,p j .
)
- i
; ! }
w.: - - 0001 152 O
7 . eg
'..y?$, ;I . U ::
i n' ~ t. ; U r e.-=* _ k
'b.
'.\.%
Ns
\ 'hY a h. .g k, gli r : $s s .
- s. L ? . fji h5*
3 ~5hIg
% ',;n -
'p3 1 ,N ' 6
- w. : E
\ sr V.,i. ' N' ~
i.; f
%. \r ,,a. - . .s
\ 'i , e
}3 - ,
[ . s
/ .
,i,'? 4 -
x/i b
-+! ,f (
hl1 ?
\l\. \.
\: w08
, 'y
\
\ .\ im r;
N
\\ 6. . <
1-
\
14 . , j
.\ ti \1 ,;
.' ?
\ '. i '\
-.;b
\' fl
/
L:l;; *
. ) Y'l, f .
'l- '
l ,.;[
, t i
.k j i - ,
't i / l ,
l j . >
.. Jl
! ' l l '
l
) ,! 'l~
j . I
~
jm l ~j l, -
.i l
f
- = :' ?
_! ti ',- ,
~..
l:; , j .
$. 1 t
l
'i
- i U '
/
9 Niif f*
.g
' }\ 4
{ j . i . l
!'1y):a) ll A
, a .e'/ / /
m.
'i ;i 'i
<- .! /)
\ ..
kl j [
/ /-
0001 ;53 O l' . i; f ) /u ,
.fj ~ .m ul .
.}}