ONS-2018-016, Calculation 0079-0191-CALC-002, Induced Differential Voltage in Control Cables.: Difference between revisions
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{{#Wiki_filter: | {{#Wiki_filter:mMPR Induced Differential Voltage in Control Cables Record No: 0079,.019l~CALC-002 Revision::.O Prepared fo.r: Otohee 1, 2 & 3 I | ||
.O Prepared fo.r: Otohee 1, 2 & 3 I Name Rolf,l | Name Rolf,l StgnatureJDat. | ||
* John Cunningham on 2-016.01-08' 18t15: 54 | Btfan Curran Preparer &1. E-sfgned by, Brian'Cumio on 2016-01-0818:14:55 John cunnlngnarn Cheeker Ill }Ohn | ||
*of Compffanc* | !:-signed by: Michael Katahata on beh91f of CunniMham on 2016*0l*06 l8:16:3S John Cunningham Reviewer llJ E-sfgned*bYt- Mldiael Katatrara-0n behalf of | ||
* John Cunningham on 2-016.01-08' 18t15:54 I | |||
&signed by: Mlctlael Katahara Michael Katahara Approver Ol1'2016-0Ul8 l8:17'°7 QA Stateme.nt*of Compffanc* | |||
Thi&- d0tument.l1a.S beert*prepared, reviewed, and approved ln ac.c~.rdai'lce: with the .Quality Assurance requlrementirotthe: MPR Standard Quality Program, Ml'R As$Qelates. l11c. | |||
2016-01*0818 | Crcat.ed: 2016-01*0818:17:07 3iO 1(1.ng St. | ||
: 17: 07 | * Alexalidrla, VA 22314 Project*T.;sk No. 0079lSl9*0191 l703l 519*02-0Q r www.mpr,com | ||
* Alexalidrla, VA 22314 l703l 519*02-0Q r www. | |||
Calcuration No.: | |||
mMPR 0079-0191-CALC-002 MPR Associates, Inc. Revision Nox O 320 King Street Alexandria., VA .22314 Pag~No.: 2 RECORD OF REVISIONS. | |||
Revision Affected Pages Description 0 AU Initial Issue | |||
Calculation No~:: | |||
, the-voltage expected to be induced ,*ou*acontrof cable by a powex: , cable | 0079-019!'-0ALC-002 MPR AsS<lciates, Inc. Revision No;: O 320 King Street Ale:xandrtcJ,,,VA 22314 Page No:: 3 Table of Contents 1.1 Back~ound ......*.................,.................................................... ,.........,..............,. ............. J 1.1, Purpose ....................................................................." ........................................ M , *** * **** 1 2.0 Summary of Results and Conclusion.,................................~**********"*************"********** 1 | ||
This* calculation u es conservative geometrical arrangemeots of the cables that are *intended. to bound the , | .J..O Methodology;. .......... .........., ....."".~-********.. *******,. "'********,-,.t--*****-.,............~********-:*.,***** *****************,*<<** 2' 3.-l Acce,ptance C.r iteria ...............................,............................ ,.......................................... 2 4.U Assumptlons:.,....*....*...*.."...................- ....... r. . . . . . . . . ... . . . . . . . . . . . . .. ................ . . . . ... . . . . . . . . . . . . . ...._. . ... . ~.!*"** 2 | ||
: 4. I *uuvedfied.Assumptions ................ - ............. ,......................... ,.,.,~ ............ ......~ ........... ,. .....2 4,Z Verified ,A:ssumptiott ...........................,.. ,.......................................................... ,............2. | |||
4;3 Limitatio$.................................................................................................................... 2 5.0 Des~gn*Jnpum*. !' ..... . . . . ....... . . .. ....... .. . . ... . . . . . . . . . . .. .... . . ................... .,,.. ........ . . . . .. .. . . . .. ... - ...... .., ...... .,. .. , . . ....... , ... 3 | |||
: 5. 1 Efectri(?a.lr".~' ~i.:~,. ~....... 11 * . . . . . . . 10 . . ... . .. . . . ""' lt" ..... ,;.................. . . ....... * ~*:;,,, . ....:*.*;** ., .... ****~ ~~***** .......,. ........ ~,. ..... . . ....... .,..,. ~*~* 't..;; .. -. ....... *,.,J 5.2 Geometry .................... **-**** ...,............. .............................. : ..... ~ .......... .. . ...... . 3 6.0 -Calculations and Results ......... ......,. ..... ..................... _ ................, .......................................... 7 6.i Electrostatib Coupling to the Control Cables ........................................................ ,v .... 7 6.20 ,Magnetic.Coupling to the Control Gab-le Coilduetors,.............. u . ..... .................. . .......... 7 6.3 Magnetic Coupling to the,C6nt:rol Cable Aim.or ........................................................ 10 6.4** Effect of Artnor................................. ,...*..*............*........*.*. .. ,~................................... ,.10 7..0 References .,............... Jlf. . . . . . . . .. .. . . ... . . . . ..... .. . . . . . . .--. . . . ... . . . ... ..... . . . . . . . . .............. . .. .. . .. . . . . . . . . . . . .. . . . . . . . . . . . . ,;-.,,.. . . . . . 12 | |||
Calcula1ion No.: | |||
mMPR 0079-0 l 91-GALC-002 MPR Associates, Inc. Revision NCY.: O 320 King Street Alexandria, VA 22314 Page No.: l | |||
==1.0 BACKGROUND== | |||
AND PW~POSE 1.1 Background Oconee Nuclear tation ( $) engineering perfonned testing on. a mock-up of medium-,.voltage cables .in proximity to DC control cables., The purpQse ofthe testingwas to investigate the effects of a medium voltage line to ground sho.rt circuit fault on nearby control cables. The te t involved a parallel run of medium voltage and control cable in a representative cable tray. The. | |||
length of the cable run was approximately 12 feet with the fault site located. in the middle of the 1- foot run of medium voltage cable. | |||
The fault test data indicates that a voltage was pre ent on the control cable during the testing. | |||
0 ngineering r ports that.th voltage was present for. the pre-test circuit calibration as well as various test c-0nfiguration and the magnitude of the voltage was not dependent upon the eparation between the.control cable and power cable. Based on the likelihood that the measured voltage was,induced as a result of 1he test cell configuratiQn (Le..test.configuration noise)~ this caJcufation determines,the-voltage expected to be induced,*ou*acontrof cable by a powex:,cable fault current u ing analytical methods rather than extrapolating th.e voltages measured during testing. | |||
1.2 Purpose The purp0se of this calculation is to estimate the magnitude of the differential voltage :induced on a two conductor circuit as a re ult of a short circuit on a nearby parallel medium voltage pQwer cable. The control cable is armored.and shielded with the configuration of interest being the armor grounded at both ends of the cable and the hieJd floating not grounded). This* calculation u es conservative geometrical arrangemeots of the cables that are *intended. to bound the, configuration o( concern for conee / Keo wee control and power cable routing. | |||
2.0 | |||
==SUMMARY== | ==SUMMARY== | ||
OF RESULTS AND CONCLUSION The differential voltage induced on a 300 foot length of unarmored, un hielded co*ntrol cable during a short | OF RESULTS AND CONCLUSION The differential voltage induced on a 300 foot length of unarmored, un hielded co*ntrol cable during a short circuit event on a nearby medium voltage cable i approximately 12 volts. This differenti.al voltage reduce to less than one volt when shielding effects of the galvanized-steel interlocked armor are considered. The actual control cable at Oconee has both a teel atmo.r jacket and a copper shield, thus the differential voltage induced in it will be lower still. | ||
.al voltage reduce to less than one volt | 'The common mode voltage is between. both cables and ground and does not appear across the load tenninals, but from both load terminals to ground. It does not actuate the load but.instead it challenges the diet ctric strength*of th'e insu lating material at the load. The common mode voltage is calculated to be approximately 712 volts for unarmored, unshielded cable~ and 1.4 volts for the armored cable. | ||
The actual control | |||
mMPR MPR | Calculation No:: | ||
mMPR 0079-0 t91-CAJ,C-002 MPR Associates, Inc;. Revision No.:. Q 320-Klng ~treet Alexandria.VA 22314 Page No;;.. 2 3.0 METHODOLOGY this calculation considers electrostatic,(capacitive -and magnetic (inductive coupling modes. | |||
This calculation does not consider couplingthrough electromagnetic radiation. Modeling of coupUng due to radiation.couplingjs.unnecessacyJqr this calculation.due*to the geometry of* | |||
Modeling of coupUng due to radiation.couplingjs | interesti::rfcomparison tO' the.wa,velerigth orthe 60Hz shotrcirctrit*wav-eform. | ||
.unnecessacyJqr this | This calculation uses the partial inductance approach for catcuJating induced voltage on individual circuit elements. See IEEE Paper titled "Partial Inductance/ (Referenc.e 2), for* | ||
*wav-eform. | further discussion on tbe partial inductance drcuif-solving-methodology., | ||
This calculation uses the partial inductance approach for | An estimate for the differential voltage.on the,two*conductofS'is de'1eloped. Nominal values,of the RMS'.sltort circuit curretttr(ise'}~ cabie length *(11), fault ]ocation (lr), ;5eparation of the me~il)i:P voltage cabJe to control cable (d};tv-cc). and maxjmum separation of the control cable conductors | ||
Nominal values , of the RMS'.sltort circuit curretttr(ise'}~ | ( ~c.ce) are used, but the methpdology is applicable to other lengths and configurations. | ||
cabie length *( | 3; 1 A'l:ceptance Criteria There arena acceptance criteria for this calculation. | ||
and maxjmum separation of the control cable conductors ( ~c.ce) are used, but the methpdology is applicable to other lengths and configurations. | 4.0 ASSUMPTIONS. | ||
3; 1 A'l: | 4.1 Unverified Assumptions | ||
4.0 | : 1. None. | ||
: 2. The thickness of the power cable insulation | 4.2 V:erifled Assumptlotis-L The-twist of the cont:rh.Fcable>conductor.s along the core:-of1he bundle.is ignored. This is a conservative as umption as tlie twisting of the conductors wou.fd have the-effect of reducing the induce&voltage. | ||
.shield iSsnot.speciffed in the O:N~ procurement specification Referenc 6). A smaller'Value is conservative for this caJculati:on. | : 2. The thickness of the power cable insulation.shield iSsnot.speciffed in the O:N~ | ||
therefore the.thickness will be assumed to be zero. 3. The-geometrical cross sectional arrangement oftbe control cable can reasonably be assumed to be-cii; | procurement specification Referenc 6). A smaller'Value is conservative for this caJculati:on. therefore the.thickness will be assumed to be zero. | ||
4.3 | : 3. The-geometrical cross sectional arrangement oftbe control cable can reasonably be assumed to be-cii;cular for U1e-purpose o:t'estimatingrseparatioo distance,between: control cabJe conductors. TI1is assumption is appropriate due to the steel armor that en.oirclesthe cable and does not require furthe.r validation. | ||
* MPR AssociateS'. Inc. 320 King Street | 4.3 Limitations, L The predominant frequency of interest is 60Hz. The.wavelength of a 60Hz signal is ignificantly longer: than. the geometry of interest Higher freque.ncy applications may | ||
.002 Revision | :require additional analysi approaches and-consjderatibns. | ||
; 5.0 , | |||
; separation of the mediwn voltage and power cables along this 300 footlen~tl is conservatively set to 3 | Calculation Na.:,, | ||
* inches, which is th.e , minimum spacing ,.o'f two neighboring embedded-~abte. duets (see.Reference | * MPR AssociateS'. Inc. | ||
-! I). Tbe edge-to-edg~ | 320 King Street AlexandriarVA 22314 0079-0191,..CALC-.002 Revision Noo: O PageNo.! 3 | ||
.separation of ilie medium voltage and power-cables along after the 300 foot length is arranged suchtharthe mutual inductance between the cables is negligib'le (Assumption 2 in eotion 4.1 , . The total length of the power and control c.ables , Lt, is , approximately 2000 meters (6562 feet). The eables are evaluate~ | : 2. !his calcuJation does not coriside'iritdiated electtomagi;ietic coupling meclfanisms; 5.0 ,DESIGN INPUTS 6.1 Electrical L The cable run of interest is a 300 "foot length where medium voltage powercable!i' are routed near low voltage,_control cabTes. After the 300 foot length; the cable diverge in a manner where the mutual inductance between t.he cables is negligible an.d therefore coupling between the cables- can 'be neglected Reference 3). | ||
as thougjl they~re parallel for a length of.-?'tA;metets (300feef}. | : 2. 'Ille- short circuit current js assumed to be l 6k:A peak ba ed on.input from Oco:rtee engineers (R-eferen~e 4 . ]nis value,is being.re,-evaluate4 by the $ite and they expe_c:t to conclude a lower value is more appropriate which woul.d make,the results in this, qalculation cons~rvatively high, and bounding._ | ||
The edge , to edge | 5.2* Geometry 11le total length of the power*a11d oontrolcables between Keowee*and Ocone'.e is appro1Citn:ately 2000 meters. However, the cables are only routed in near vicinity of each other for a distance of approxfruately 300 feet before the routing of tlte cables diverge away from each other (Segment | ||
mMPR MPR Associates , Inc. | #7 -see Reference l 0). The edge-to-edge;separation of the mediwn voltage and power cables along this 300 footlen~tl is conservatively set to 3 *inches, which is th.e,minimum spacing,.o'f two neighboring embedded-~abte. duets (see.Reference-! I). Tbe edge-to-edg~.separation of ilie medium voltage and power- cables along after the 300 foot length is arranged suchtharthe mutual inductance between the cables is negligib'le (Assumption 2 in eotion 4.1 , . | ||
The total length of the power and control c.ables, Lt, is,approximately 2000 meters (6562 feet). | |||
The eables are evaluate~ as thougjl they~re parallel for a length of.-?'tA;metets (300feef}. The edge,to edge separation,o.f the power and control cab1es;over the 300 foot. length dseii,is7.6 cm 3 inches). See Figure 1. | |||
* | |||
References | Calculation No,; | ||
* 6 and 7 Conductor Shield Thickness. | mMPR 0079-0191-CAtC-002 MPR Associates, Inc. Revision No:: O 320 King *Street Alexandria, VA 2.2314 Page No:: 4 Figure. 1. Cable Run Dimensions. | ||
Ost)., -0.020"' Reference , 6. minimum | Figure 2 i a configuration ketch of a typical lrielded control cable with cabJe armor,. cable hield multiple co1Jductor and multiple jacket/ insa]ation layers. Table 1 summarizes relevant control cable dimensions and properties. Table 2 summarizes relevant power cable dimensions and properties. | ||
I Calculatton *No~: | |||
mMPR 0079-0 l9l'-ALC-002 MPR Associates, lno. Revision No.; O 320 King.Street Alexandrlar VA 22314 Page No.: 5 Om Ccmponent (1) | |||
Figure 2. Cross Sectfon View*ofTypical Ccmtrol Cable Table 1. Parameters for. a Typical Keowee Control Csbte Parameter Rating Dimension. References. | |||
: EPR 0.260'' Reference | Controt Conductor Olameta:r, De 9AWG 0.131 .. Reference-5 Conductor Insulation Thickness. References XLPE 0.0475" Equano (0.226"*0.131j/2 Di.cc Shield Wtdth, D. n.ec Copper,Tape 0,005~ Reference*.!> | ||
Max IO' Shield, 010 - 0.766" Reference 5, Equal to.o.775~* | |||
TI1e edge" to edge separation of the power. and *control | 0.002."'.0.005~..0.002" Steel.Amlor Thicl<ness, o_ | ||
Galvanized 0.025" Reference 5, Minimum Slee! | |||
Tabte 2. Parameters for a Representative Keowee Power Cable Parameter Rating Dimension References Power Conductor Diameter 750MCM 0.998" References*6 and 7 Conductor Shield Thickness. Ost)., | |||
Ml/ | |||
- 0.020"' Reference,6. minimum | |||
*Calculation No.-: | |||
mMPR 0079-0191-CALC-OOZ MPR Associates, Inc. Revision No,; o. | |||
320 King Street Alexandria;.VA 22314 PageNo.: | |||
* 6 Table, 2. Parameters for a Representative' Keoweec Power able Parameter Rating* Dimension References* | |||
Cood,tJctor EPR~in$ulation: EPR 0 .260'' Reference 6i minimum Thickness, 01-MV Them,oset Reference 6, Secifon 4.1 Insulation Shield Thickness.., OMh Unknown Compound Conservatively setto. 0.000" Shield/Armor Tape Thickness, Non-Magnetic Bronze | |||
* 0.020" ReferenGe.6. minimum DMV41* | |||
CabltUacket Thickness, DJac Hypi!lon 0;110~ Reference 6, minimum 5.2.1 Power/ Control Cable Separation (dMV..cc) | |||
TI1e edge"to edge separation of the power.and *control cables, dsep,Js 7:6 cm (3 inches}~. Thlf edge to edge separation of the medium voltage cable: to the nearest contro1 cable dMv-cc is calculated as follows~ | |||
dMv-cc= 3.000''+ 0.020'' + .260'.t'!lf- 0.000'1 + 0.0201,1 + OJ.l O",+ 0.025'' + 0.005'!*~ 0.0475:" | |||
d MV'-CC = 3.488 11 5.2.2 Maximum Control Cable Conductor Se,par.ation Tlie magnitude of differential voltage induced*in a conttoJ cahJe pair: is a function of the separation of the control cables and the current of the current source. The> maximum possible eparation ofa conductor pair in the control cable bundle occurs when th.e conductors in the pair are diametricaJly opposed with the outermost edge of each of the conductors at opposite ends of the bundle. See figure3 , | |||
The m~imum*separation of two conductors, d e- c .is ca.lculated as follows: | |||
dee-cc= 0.766"., ( 2 | |||
* 0.0475° ).-{2 | * 0.0475° ).-{2 | ||
* 0.13'1"), = 0.409" mMPR | * 0.13'1"), = 0.409" | ||
6 .. 1 | |||
Calculation No.: | |||
The mutual indu.ctance, Mp, between anytwo*conductors is.equal to: | mMPR 0079-0191-CALC-002 MPR Associates, Inc. Revision No,~ 0 320 King Street Alexandria, VA 22314 Page No.: 7' Figure 3. Maximum Control Conductor Separation. | ||
6.0 C ALCULATIONS AND RESULTS ThefoUowing ections develop the approach.fore timating *the voltage induced on the conductors of a bundled control cable"pair with the cable armot grounded at both ends.and..the ab.le shield.floating. | |||
: | 6..1 Elec.trostatic. Coupling to the Control Cables The cable armor being grounded at both ends precludes capacitive coupling from the nearby medium voltage cable to th low voltage control cables and to the low voltage control cable armor. ee GER-3205 (Reference 8) for additional infonnation. | ||
;o:& | 6.2 Magneti.c Coup/Ing to the Control Cable Conductors The predominant coupling mechanism is magnetic coupling to the low voltage control eables. | ||
The magnetic.field coupled between the .MV conductor and the control cab.le is proportional to the mutual inductance between th.e MV cable and the LV conductors. The mutual indu.ctance, Mp, between anytwo *conductors is.equal to: | |||
p | |||
Where: , length | µo 1 . lf,d) := -*Ir I It * | ||
({ HJ M J lr | |||
-.+ | |||
~= Mp(l;.dcCi_Cc) | cl | ||
. I( | |||
1+ - | |||
. | d. | ||
2 | |||
- l i | |||
+- + - | |||
'r 2 | |||
. | d f (Reference 2) | ||
-: | C'alcutation,No.,: | ||
mMPR 0079-0191:-CALC-002 MPR Associates, Inc. Revision No.: O 320 King Street Alexandria, VA 22314 Page No.: ~ | |||
* | Wherer | ||
, , | µo = Permittivity;o:&free space, 41T*10'1 :H/m Ir = The length of the parallel current carrying con~u:ctO.fb"': | ||
;. | d = "The separation between .the two paralle.1 conductors,; | ||
The,len~h ,ofthe control cable that isJmmune to magnetic coupling has a self partial inductance, Lp, which must be considered to complete the cable loop. Theo-self partial inductance, Lr, of a, conductor fo a conducto-r pair is equal to~ | |||
(Re:fufence2) | |||
Where: , | |||
length = TJ1e length of the cable. | |||
r The radius ofth:e control cable conductor. | |||
The ciniuitresulting~om the self and mutual partial .ipductances is shown in Figore 4,. with the fo11owing:values: | |||
. | - 4***.* | ||
* | Lp:._ce:1:a:= 1.,(lr,r9 wa) Lp_c 1a= L9s6 1p ff | ||
-4 4>_cq;a := 1p 1f.r9Awo) Lp_cc2 a-- l.986x 'IO H | |||
-3 Lp_CClh ,=~(1t- 1r,l'?A wo) Lp_CCJl.>=, 5..304 10 H | |||
_ 3: | |||
. | 4*:_CG:2b?"" 11,(It - lc,t5M:wG) Lp_ccztr s.so4~:10 R | ||
.: | -4 M:MV_CCJ ;.... Mp(1r , <1Mv_cc) MMV_C 1= L213>< .10 ff | ||
-4 MMv_cci 1=Mp(1f.dror_cc+ 0cc_cd MMv.:..c c2"" Ll93:.: lO H 4 | |||
Mcc1a::_CC2a ~= Mp(l;.dcCi_Cc) Mc;c1a~GC2a"" l ,605x ilf 'Ff | |||
-;3 Mcc1b_CC2b := Mp(~ - 1 r,dcc_cc) M | |||
- | |||
lb CC2b= 4.Slx JO | |||
' | |||
H | |||
* | Calculation.No.: | ||
mMPR 0079-0 I 91-'ALC-002 MPR ASS()ciates, Inc. ReVision No.: 0 320 KJng Street Alexandria, VA 2'2314* PageNo.: 9 | |||
: | ,~- | ||
figµre 4'., Self afiil Mutual ParttaJ Inductance Circuit 6.2.,1 Common Mode Voltage, No Armor Shielding . | |||
The common mode voltage*in the controJ conductor circuit is the voltagejnduced due to the mutual partial inductance between the medium voltag¢ cable and the return leg of the control cable loop. The common mode voltage, without consideration of armor shielding. effects; Vcommpn,,is calculated as follows: | |||
IVcommon! = 7195V 6.2.2 Differential Voltage, No Armor Shielding The differential voltage at the load end of the control circuit is a. .function of the load current. the medium voltage, l1ort circuit urrent, an~the elf and mutual inductances hown in Figure 4. | |||
The differential load voltage can be,calculated.as. | |||
mMPR -Catculii<<on !'J<F 0079--0191 ..&A:I.:G:-002' MPR Associates, Inc. ..RE'Msion No:t O, 320. King ~feet Alexandn~_NA 223.14 . . Pag~J\10;$ 1W 1 | |||
Vtooo:-Di:fl oontrokisc) _:;= l_ ,_**~_P_<<,_c_-_r._~ *oo_-_ii_*ttu_l -J~-~CGla,,j:J_* zJ_ oo_--ntrot*~:; J*--*_"i' ' | |||
c_ | |||
+J *o:t*f:l!" conicontrcit -:J*co*Mec111: ec2-#coritrol ** | |||
, | +i-©~Mfui:*CG t~c | ||
' | + lJ-fJl*Lp ct2lfoontrol *- J:~MCCJa 6C2ifoontrot *** | ||
+j *m*~- :. | |||
.... | |||
_cc2olcon1;roL -J*(l}*Mtt.1b_0c2{/<X}ntrot ,, | |||
j | |||
++<u*MM-V.:.Cm~ | |||
Tiie-differ,¢.ntial foad'VoJfage.for.-0t1aiJ1!9~ed.unsbielde~ c:ontrofcable;. d~e,~o sho.rt circ9jfevent ,a JS! | |||
6.3 Magnetic* Coupling to ,th~.co.ntrol Cable Armor The control cable anno.r is grounded atbotb ends ot'.the..aQ:Uor. - Il:ds-*eon:fi;gw:ation_ct:eates.a,fo-0p, of imprecise g;i;}gmetfy coilsisting,oflireamiQr and the statiort gr~und bus., 'I11t'self and.~litoal. | |||
partial inductance o-f the-,armor and the:ground bus can be-:estimated usingth~:abnve;formulae.1 hµUhe'Calculatfon*'ii(not necessary"as the voJtag,e 1nd~ce~:m the armorwm raprdty'coriducrno g~c;mnd. Coupling fr<;>1n the annor to*the-ccmductor.:will be a~econd or4er-effect*-and'ihus, significh:ntlt tower than:the values cafou:fate:d above; Th'is- approach is consiste.nt'with the approach ,discussed :in GER...3205,(Refe~nce.8-:}~, | |||
6.4 Effect of Armor | |||
'flie control '<:abfe,anJJ.Or il gah:*anize,g;$tauil¢ss*st~e1,, '\\'~!Ch acts as a low rel~ctatice p~~ for the magnetic ,flqx due to the shortcircuit/;mment insthe medjum; voltage cable; TI1e armor (shield), | |||
' has _the effect_of diverting-the flux awa'Y,: from lliezlow.VQltage .cot1clucto1'.~ | |||
Rosa derives:th_e self and mutuallnduetance.of conductors by, cafou1atmg.t be total H :6¢h;[ that collapses,upon,a conductor wlicna cutfont;i.u~moved from,th:at ¢onductor.(Refer.ence..9,}. *This approach includes. anSroplicit assumption thatthe.medium, of tbat conductori.i; :tmiform: | |||
* Consideration ofthe eftect.ofaJow reluctance armor/shield. upon.the workof:.Rosaas.applied to the ONS.scenario_;friflow:s.: - | |||
Tl1e-introduction *0£ a lowitelucta:nee steeLarmorishield.inthe,:flux fiel.d 'o f a,conducto,r has-.tlittle to no effect on. the J>ar_tial~elfinducfrtnce!q_f.a coricfuctbi\ The sliield 1vHI'fi]!ve:a liJghet fl:~. | |||
density than the.surrounding-air but:does not change the behavior of tbeH field upott' remo.vat of tµe current Namely t:hattl1efie)d collapse.s*upon tliewire in the same mann_e r~ ft~ouldiftliere werll:nQ shield ptt?sentf Sitnilariy; th:e *introduction of a-shield wilt haV<YttegligibieJmpairt. orrthe:~ | |||
partfal *mutna.l i:ridilotance.bet.ween tw9 .cond11ctors *that are bo\Jiwitliin the same .shield.- | |||
L _ _ _ _ _ __ | |||
Calculation No.; | |||
mMPR 0079-0191-CALC: ooz MPR Associates, Inc. Revision No,: O 320 King .Street Alexandria. VA 223:14 Page No;: 11 TI1e introduction of?, low reluctance steel.armor/shield in the:flux field:ofa,conductor will.affect the partial mutual inductance between two conductors. Once again .the-shield bas a higbe.r flux. | |||
density ~an the urrounding.air. However wl1en current is removed from the primacy conductor the.rumor/shield will divert flux away from the econdazy ,conductor thereby reducing the magnitude*offlux that,cQ.Jfapses upo,n the secondary ct.~tiducfor. | |||
IPR Cafoulation0079,.:0191~CALC-003, (Reference 12) estimates the effectiveness of the steel armor to shield conductors from external fields. The calculation determines that the armor reduces the fieid internaJ to the annor by a factor of approximately 9So/&' (i.e. the field .internal. to the shield is*approximately 2% of what it would be if the shield were-not present). | |||
6.4.1 Common Mode Voltage:, With Armor Shielding The common mode voltage-in the control conductorcircu.it is the voltage induced due.to the mutual partial inductance between the mediwn voltage cable*and the return Jeg of the control cable loop. TI1e common mode voJtag~ with consideration of armor shielding effects; Vsbie.lded;JXlll1mOn, is calculated as follows~ . | |||
2 SE:.-- *- | |||
100 shietdtd_comr:u,n~""' SE* IV<:ommonl 6.4.2 Differential'Voltage No Armor Shielding Thecontmon mode' voltage lo the control conductor circuit is thevoltage induced due to(th:e mutual -partial inducUl,llce between the.medium voltage cable and the .return leg of the i;ontrol cable loop-. 'The common mod.e voltage :with consideration of armor shielding effectsc, V s hitldlidi,Load.:;.Ditr, js -calculated as follows: | |||
Calculation No~:, | |||
mMPR 0079-019l;C'AI:.Cw002 MPR Associates, Inc, Revision No;:. o 320 King Street Alexandri~i-VA 22314' Page No:: 12 7 .0 REFERENe'ES | |||
: 1. IBEE 518-1982 1EEE Guide for th/e Installation ofElectrical Equipment to Mi11.im,ize Electrical .N.oiselnputs to Controllers from &temal Sources; | |||
: 2. Article by Cla)'forf R: Paul, ''PartJal'lnductance.;1 IE.EB .EMC Society Magazine, ~2Ql0. | |||
: 3. Email from Bernard A. Norwood ONS) to Michael Katahara (MPR), Re: QUESTION ALERT - Oconee Control Cable Anafysis. Tuesday December 29, 2015 3:38PM.. | |||
: 4. Email from .Bernard::A. Norwood (ONS) to MichaelKatah_ara (MPR , Re,'. Oconee-induced: | |||
Voltage Update. Wednesday December30;-20l5, l:57PM'. , | |||
: 5. Rockbestos Product peci6cation Drawing,. VC9AWG Clas.s lE JOOOV Hypalon ln:ner' | |||
.Jacket GSJA PVC Outer Jacket Nuclear 'afetJl Related, Duke EnergyCorporaiton; Keowee Cable Upgrade. -Dated 5/09/2001. | |||
: 6. Oconee Nuclear Specification Number OSS--139:00.-00-00lO, Keowee Underground'. | |||
Replacement Medium Voltage Single Conductor /!owe,: Cable. Revised January ~" 2002. | |||
: 7. Amold" Thomas and Mercier~David C., Sauthwit:e Power able Manuai~ Fourth:Edition~ | |||
8~ General Electdc: -C~ER-3205, TJteory,ofSJii:eldi'ng andGroUJ1ding ofControl Cables to-Reduce Surges. October 5 1973'. | |||
: 9. Ro a, Edward, B, Bulletin ofthe National Bureau ofStandards, Volume 4 Number 2, the Selfand Mutual Inductances,ofLinear Conductors. | |||
l (},, Oconee Nuclear: St~ltibn drawing:0-398-Al- l 07, Revision 1 "FSW Duetbank. Segment #7, Plan & Elevation. | |||
: 11. Oconee Nuclear Station drawing 0-398-Al-200B Revi ion O "PSW Ductban~ Ducthank Reinforcement Sections B & C." | |||
12~ MPRCalcufa:tion 0079-0191-CALC-003. Finite Eleme'nt Analysi.flo,Calculate Sh'ielding' Effectiveness. Revision 0. -}} |
Revision as of 21:39, 21 October 2019
ML18046A073 | |
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Site: | Oconee ![]() |
Issue date: | 02/12/2018 |
From: | Duke Energy Carolinas, MPR Associates |
To: | Office of Nuclear Reactor Regulation |
Shared Package | |
ML18046A090 | List:
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References | |
ONS-2018-016 0079-0191-CALC-002 | |
Download: ML18046A073 (15) | |
Text
{{#Wiki_filter:mMPR Induced Differential Voltage in Control Cables Record No: 0079,.019l~CALC-002 Revision::.O Prepared fo.r: Otohee 1, 2 & 3 I Name Rolf,l StgnatureJDat. Btfan Curran Preparer &1. E-sfgned by, Brian'Cumio on 2016-01-0818:14:55 John cunnlngnarn Cheeker Ill }Ohn
!:-signed by: Michael Katahata on beh91f of CunniMham on 2016*0l*06 l8:16:3S John Cunningham Reviewer llJ E-sfgned*bYt- Mldiael Katatrara-0n behalf of
- John Cunningham on 2-016.01-08' 18t15:54 I
&signed by: Mlctlael Katahara Michael Katahara Approver Ol1'2016-0Ul8 l8:17'°7 QA Stateme.nt*of Compffanc*
Thi&- d0tument.l1a.S beert*prepared, reviewed, and approved ln ac.c~.rdai'lce: with the .Quality Assurance requlrementirotthe: MPR Standard Quality Program, Ml'R As$Qelates. l11c. Crcat.ed: 2016-01*0818:17:07 3iO 1(1.ng St.
- Alexalidrla, VA 22314 Project*T.;sk No. 0079lSl9*0191 l703l 519*02-0Q r www.mpr,com
Calcuration No.: mMPR 0079-0191-CALC-002 MPR Associates, Inc. Revision Nox O 320 King Street Alexandria., VA .22314 Pag~No.: 2 RECORD OF REVISIONS. Revision Affected Pages Description 0 AU Initial Issue
Calculation No~:: 0079-019!'-0ALC-002 MPR AsS<lciates, Inc. Revision No;: O 320 King Street Ale:xandrtcJ,,,VA 22314 Page No:: 3 Table of Contents 1.1 Back~ound ......*.................,.................................................... ,.........,..............,. ............. J 1.1, Purpose ....................................................................." ........................................ M , *** * **** 1 2.0 Summary of Results and Conclusion.,................................~**********"*************"********** 1
.J..O Methodology;. .......... .........., ....."".~-********.. *******,. "'********,-,.t--*****-.,............~********-:*.,***** *****************,*<<** 2' 3.-l Acce,ptance C.r iteria ...............................,............................ ,.......................................... 2 4.U Assumptlons:.,....*....*...*.."...................- ....... r. . . . . . . . . ... . . . . . . . . . . . . .. ................ . . . . ... . . . . . . . . . . . . . ...._. . ... . ~.!*"** 2
- 4. I *uuvedfied.Assumptions ................ - ............. ,......................... ,.,.,~ ............ ......~ ........... ,. .....2 4,Z Verified ,A:ssumptiott ...........................,.. ,.......................................................... ,............2.
4;3 Limitatio$.................................................................................................................... 2 5.0 Des~gn*Jnpum*. !' ..... . . . . ....... . . .. ....... .. . . ... . . . . . . . . . . .. .... . . ................... .,,.. ........ . . . . .. .. . . . .. ... - ...... .., ...... .,. .. , . . ....... , ... 3
- 5. 1 Efectri(?a.lr".~' ~i.:~,. ~....... 11 * . . . . . . . 10 . . ... . .. . . . ""' lt" ..... ,;.................. . . ....... * ~*:;,,, . ....:*.*;** ., .... ****~ ~~***** .......,. ........ ~,. ..... . . ....... .,..,. ~*~* 't..;; .. -. ....... *,.,J 5.2 Geometry .................... **-**** ...,............. .............................. : ..... ~ .......... .. . ...... . 3 6.0 -Calculations and Results ......... ......,. ..... ..................... _ ................, .......................................... 7 6.i Electrostatib Coupling to the Control Cables ........................................................ ,v .... 7 6.20 ,Magnetic.Coupling to the Control Gab-le Coilduetors,.............. u . ..... .................. . .......... 7 6.3 Magnetic Coupling to the,C6nt:rol Cable Aim.or ........................................................ 10 6.4** Effect of Artnor................................. ,...*..*............*........*.*. .. ,~................................... ,.10 7..0 References .,............... Jlf. . . . . . . . .. .. . . ... . . . . ..... .. . . . . . . .--. . . . ... . . . ... ..... . . . . . . . . .............. . .. .. . .. . . . . . . . . . . . .. . . . . . . . . . . . . ,;-.,,.. . . . . . 12
Calcula1ion No.: mMPR 0079-0 l 91-GALC-002 MPR Associates, Inc. Revision NCY.: O 320 King Street Alexandria, VA 22314 Page No.: l
1.0 BACKGROUND
AND PW~POSE 1.1 Background Oconee Nuclear tation ( $) engineering perfonned testing on. a mock-up of medium-,.voltage cables .in proximity to DC control cables., The purpQse ofthe testingwas to investigate the effects of a medium voltage line to ground sho.rt circuit fault on nearby control cables. The te t involved a parallel run of medium voltage and control cable in a representative cable tray. The. length of the cable run was approximately 12 feet with the fault site located. in the middle of the 1- foot run of medium voltage cable. The fault test data indicates that a voltage was pre ent on the control cable during the testing. 0 ngineering r ports that.th voltage was present for. the pre-test circuit calibration as well as various test c-0nfiguration and the magnitude of the voltage was not dependent upon the eparation between the.control cable and power cable. Based on the likelihood that the measured voltage was,induced as a result of 1he test cell configuratiQn (Le..test.configuration noise)~ this caJcufation determines,the-voltage expected to be induced,*ou*acontrof cable by a powex:,cable fault current u ing analytical methods rather than extrapolating th.e voltages measured during testing. 1.2 Purpose The purp0se of this calculation is to estimate the magnitude of the differential voltage :induced on a two conductor circuit as a re ult of a short circuit on a nearby parallel medium voltage pQwer cable. The control cable is armored.and shielded with the configuration of interest being the armor grounded at both ends of the cable and the hieJd floating not grounded). This* calculation u es conservative geometrical arrangemeots of the cables that are *intended. to bound the, configuration o( concern for conee / Keo wee control and power cable routing. 2.0
SUMMARY
OF RESULTS AND CONCLUSION The differential voltage induced on a 300 foot length of unarmored, un hielded co*ntrol cable during a short circuit event on a nearby medium voltage cable i approximately 12 volts. This differenti.al voltage reduce to less than one volt when shielding effects of the galvanized-steel interlocked armor are considered. The actual control cable at Oconee has both a teel atmo.r jacket and a copper shield, thus the differential voltage induced in it will be lower still.
'The common mode voltage is between. both cables and ground and does not appear across the load tenninals, but from both load terminals to ground. It does not actuate the load but.instead it challenges the diet ctric strength*of th'e insu lating material at the load. The common mode voltage is calculated to be approximately 712 volts for unarmored, unshielded cable~ and 1.4 volts for the armored cable.
Calculation No:: mMPR 0079-0 t91-CAJ,C-002 MPR Associates, Inc;. Revision No.:. Q 320-Klng ~treet Alexandria.VA 22314 Page No;;.. 2 3.0 METHODOLOGY this calculation considers electrostatic,(capacitive -and magnetic (inductive coupling modes. This calculation does not consider couplingthrough electromagnetic radiation. Modeling of coupUng due to radiation.couplingjs.unnecessacyJqr this calculation.due*to the geometry of* interesti::rfcomparison tO' the.wa,velerigth orthe 60Hz shotrcirctrit*wav-eform. This calculation uses the partial inductance approach for catcuJating induced voltage on individual circuit elements. See IEEE Paper titled "Partial Inductance/ (Referenc.e 2), for* further discussion on tbe partial inductance drcuif-solving-methodology., An estimate for the differential voltage.on the,two*conductofS'is de'1eloped. Nominal values,of the RMS'.sltort circuit curretttr(ise'}~ cabie length *(11), fault ]ocation (lr), ;5eparation of the me~il)i:P voltage cabJe to control cable (d};tv-cc). and maxjmum separation of the control cable conductors ( ~c.ce) are used, but the methpdology is applicable to other lengths and configurations. 3; 1 A'l:ceptance Criteria There arena acceptance criteria for this calculation. 4.0 ASSUMPTIONS. 4.1 Unverified Assumptions
- 1. None.
4.2 V:erifled Assumptlotis-L The-twist of the cont:rh.Fcable>conductor.s along the core:-of1he bundle.is ignored. This is a conservative as umption as tlie twisting of the conductors wou.fd have the-effect of reducing the induce&voltage.
- 2. The thickness of the power cable insulation.shield iSsnot.speciffed in the O:N~
procurement specification Referenc 6). A smaller'Value is conservative for this caJculati:on. therefore the.thickness will be assumed to be zero.
- 3. The-geometrical cross sectional arrangement oftbe control cable can reasonably be assumed to be-cii;cular for U1e-purpose o:t'estimatingrseparatioo distance,between: control cabJe conductors. TI1is assumption is appropriate due to the steel armor that en.oirclesthe cable and does not require furthe.r validation.
4.3 Limitations, L The predominant frequency of interest is 60Hz. The.wavelength of a 60Hz signal is ignificantly longer: than. the geometry of interest Higher freque.ncy applications may
- require additional analysi approaches and-consjderatibns.
Calculation Na.:,,
- MPR AssociateS'. Inc.
320 King Street AlexandriarVA 22314 0079-0191,..CALC-.002 Revision Noo: O PageNo.! 3
- 2. !his calcuJation does not coriside'iritdiated electtomagi;ietic coupling meclfanisms; 5.0 ,DESIGN INPUTS 6.1 Electrical L The cable run of interest is a 300 "foot length where medium voltage powercable!i' are routed near low voltage,_control cabTes. After the 300 foot length; the cable diverge in a manner where the mutual inductance between t.he cables is negligible an.d therefore coupling between the cables- can 'be neglected Reference 3).
- 2. 'Ille- short circuit current js assumed to be l 6k:A peak ba ed on.input from Oco:rtee engineers (R-eferen~e 4 . ]nis value,is being.re,-evaluate4 by the $ite and they expe_c:t to conclude a lower value is more appropriate which woul.d make,the results in this, qalculation cons~rvatively high, and bounding._
5.2* Geometry 11le total length of the power*a11d oontrolcables between Keowee*and Ocone'.e is appro1Citn:ately 2000 meters. However, the cables are only routed in near vicinity of each other for a distance of approxfruately 300 feet before the routing of tlte cables diverge away from each other (Segment
#7 -see Reference l 0). The edge-to-edge;separation of the mediwn voltage and power cables along this 300 footlen~tl is conservatively set to 3 *inches, which is th.e,minimum spacing,.o'f two neighboring embedded-~abte. duets (see.Reference-! I). Tbe edge-to-edg~.separation of ilie medium voltage and power- cables along after the 300 foot length is arranged suchtharthe mutual inductance between the cables is negligib'le (Assumption 2 in eotion 4.1 , .
The total length of the power and control c.ables, Lt, is,approximately 2000 meters (6562 feet). The eables are evaluate~ as thougjl they~re parallel for a length of.-?'tA;metets (300feef}. The edge,to edge separation,o.f the power and control cab1es;over the 300 foot. length dseii,is7.6 cm 3 inches). See Figure 1.
Calculation No,; mMPR 0079-0191-CAtC-002 MPR Associates, Inc. Revision No:: O 320 King *Street Alexandria, VA 2.2314 Page No:: 4 Figure. 1. Cable Run Dimensions. Figure 2 i a configuration ketch of a typical lrielded control cable with cabJe armor,. cable hield multiple co1Jductor and multiple jacket/ insa]ation layers. Table 1 summarizes relevant control cable dimensions and properties. Table 2 summarizes relevant power cable dimensions and properties.
I Calculatton *No~: mMPR 0079-0 l9l'-ALC-002 MPR Associates, lno. Revision No.; O 320 King.Street Alexandrlar VA 22314 Page No.: 5 Om Ccmponent (1) Figure 2. Cross Sectfon View*ofTypical Ccmtrol Cable Table 1. Parameters for. a Typical Keowee Control Csbte Parameter Rating Dimension. References. Controt Conductor Olameta:r, De 9AWG 0.131 .. Reference-5 Conductor Insulation Thickness. References XLPE 0.0475" Equano (0.226"*0.131j/2 Di.cc Shield Wtdth, D. n.ec Copper,Tape 0,005~ Reference*.!> Max IO' Shield, 010 - 0.766" Reference 5, Equal to.o.775~* 0.002."'.0.005~..0.002" Steel.Amlor Thicl<ness, o_ Galvanized 0.025" Reference 5, Minimum Slee! Tabte 2. Parameters for a Representative Keowee Power Cable Parameter Rating Dimension References Power Conductor Diameter 750MCM 0.998" References*6 and 7 Conductor Shield Thickness. Ost)., Ml/
- 0.020"' Reference,6. minimum
*Calculation No.-:
mMPR 0079-0191-CALC-OOZ MPR Associates, Inc. Revision No,; o. 320 King Street Alexandria;.VA 22314 PageNo.:
- 6 Table, 2. Parameters for a Representative' Keoweec Power able Parameter Rating* Dimension References*
Cood,tJctor EPR~in$ulation: EPR 0 .260 Reference 6i minimum Thickness, 01-MV Them,oset Reference 6, Secifon 4.1 Insulation Shield Thickness.., OMh Unknown Compound Conservatively setto. 0.000" Shield/Armor Tape Thickness, Non-Magnetic Bronze
- 0.020" ReferenGe.6. minimum DMV41*
CabltUacket Thickness, DJac Hypi!lon 0;110~ Reference 6, minimum 5.2.1 Power/ Control Cable Separation (dMV..cc) TI1e edge"to edge separation of the power.and *control cables, dsep,Js 7:6 cm (3 inches}~. Thlf edge to edge separation of the medium voltage cable: to the nearest contro1 cable dMv-cc is calculated as follows~ dMv-cc= 3.000+ 0.020 + .260'.t'!lf- 0.000'1 + 0.0201,1 + OJ.l O",+ 0.025 + 0.005'!*~ 0.0475:" d MV'-CC = 3.488 11 5.2.2 Maximum Control Cable Conductor Se,par.ation Tlie magnitude of differential voltage induced*in a conttoJ cahJe pair: is a function of the separation of the control cables and the current of the current source. The> maximum possible eparation ofa conductor pair in the control cable bundle occurs when th.e conductors in the pair are diametricaJly opposed with the outermost edge of each of the conductors at opposite ends of the bundle. See figure3 , The m~imum*separation of two conductors, d e- c .is ca.lculated as follows: dee-cc= 0.766"., ( 2
- 0.0475° ).-{2
- 0.13'1"), = 0.409"
Calculation No.: mMPR 0079-0191-CALC-002 MPR Associates, Inc. Revision No,~ 0 320 King Street Alexandria, VA 22314 Page No.: 7' Figure 3. Maximum Control Conductor Separation. 6.0 C ALCULATIONS AND RESULTS ThefoUowing ections develop the approach.fore timating *the voltage induced on the conductors of a bundled control cable"pair with the cable armot grounded at both ends.and..the ab.le shield.floating. 6..1 Elec.trostatic. Coupling to the Control Cables The cable armor being grounded at both ends precludes capacitive coupling from the nearby medium voltage cable to th low voltage control cables and to the low voltage control cable armor. ee GER-3205 (Reference 8) for additional infonnation. 6.2 Magneti.c Coup/Ing to the Control Cable Conductors The predominant coupling mechanism is magnetic coupling to the low voltage control eables. The magnetic.field coupled between the .MV conductor and the control cab.le is proportional to the mutual inductance between th.e MV cable and the LV conductors. The mutual indu.ctance, Mp, between anytwo *conductors is.equal to: p
µo 1 . lf,d) := -*Ir I It *
({ HJ M J lr
-.+
cl
. I(
1+ - d. 2
- l i +- + - 'r 2
d f (Reference 2)
C'alcutation,No.,: mMPR 0079-0191:-CALC-002 MPR Associates, Inc. Revision No.: O 320 King Street Alexandria, VA 22314 Page No.: ~ Wherer
µo = Permittivity;o:&free space, 41T*10'1 :H/m Ir = The length of the parallel current carrying con~u:ctO.fb"':
d = "The separation between .the two paralle.1 conductors,; The,len~h ,ofthe control cable that isJmmune to magnetic coupling has a self partial inductance, Lp, which must be considered to complete the cable loop. Theo-self partial inductance, Lr, of a, conductor fo a conducto-r pair is equal to~ (Re:fufence2) Where: , length = TJ1e length of the cable. r The radius ofth:e control cable conductor. The ciniuitresulting~om the self and mutual partial .ipductances is shown in Figore 4,. with the fo11owing:values:
- 4***.*
Lp:._ce:1:a:= 1.,(lr,r9 wa) Lp_c 1a= L9s6 1p ff
-4 4>_cq;a := 1p 1f.r9Awo) Lp_cc2 a-- l.986x 'IO H -3 Lp_CClh ,=~(1t- 1r,l'?A wo) Lp_CCJl.>=, 5..304 10 H
_ 3: 4*:_CG:2b?"" 11,(It - lc,t5M:wG) Lp_ccztr s.so4~:10 R
-4 M:MV_CCJ ;.... Mp(1r , <1Mv_cc) MMV_C 1= L213>< .10 ff -4 MMv_cci 1=Mp(1f.dror_cc+ 0cc_cd MMv.:..c c2"" Ll93:.: lO H 4
Mcc1a::_CC2a ~= Mp(l;.dcCi_Cc) Mc;c1a~GC2a"" l ,605x ilf 'Ff
-;3 Mcc1b_CC2b := Mp(~ - 1 r,dcc_cc) M -
lb CC2b= 4.Slx JO
'
H
Calculation.No.: mMPR 0079-0 I 91-'ALC-002 MPR ASS()ciates, Inc. ReVision No.: 0 320 KJng Street Alexandria, VA 2'2314* PageNo.: 9
,~-
figµre 4'., Self afiil Mutual ParttaJ Inductance Circuit 6.2.,1 Common Mode Voltage, No Armor Shielding . The common mode voltage*in the controJ conductor circuit is the voltagejnduced due to the mutual partial inductance between the medium voltag¢ cable and the return leg of the control cable loop. The common mode voltage, without consideration of armor shielding. effects; Vcommpn,,is calculated as follows: IVcommon! = 7195V 6.2.2 Differential Voltage, No Armor Shielding The differential voltage at the load end of the control circuit is a. .function of the load current. the medium voltage, l1ort circuit urrent, an~the elf and mutual inductances hown in Figure 4. The differential load voltage can be,calculated.as.
mMPR -Catculii<<on !'J<F 0079--0191 ..&A:I.:G:-002' MPR Associates, Inc. ..RE'Msion No:t O, 320. King ~feet Alexandn~_NA 223.14 . . Pag~J\10;$ 1W 1 Vtooo:-Di:fl oontrokisc) _:;= l_ ,_**~_P_<<,_c_-_r._~ *oo_-_ii_*ttu_l -J~-~CGla,,j:J_* zJ_ oo_--ntrot*~:; J*--*_"i' ' c_
+J *o:t*f:l!" conicontrcit -:J*co*Mec111: ec2-#coritrol ** +i-©~Mfui:*CG t~c + lJ-fJl*Lp ct2lfoontrol *- J:~MCCJa 6C2ifoontrot *** +j *m*~- :. ....
_cc2olcon1;roL -J*(l}*Mtt.1b_0c2{/<X}ntrot ,, j
++<u*MM-V.:.Cm~
Tiie-differ,¢.ntial foad'VoJfage.for.-0t1aiJ1!9~ed.unsbielde~ c:ontrofcable;. d~e,~o sho.rt circ9jfevent ,a JS! 6.3 Magnetic* Coupling to ,th~.co.ntrol Cable Armor The control cable anno.r is grounded atbotb ends ot'.the..aQ:Uor. - Il:ds-*eon:fi;gw:ation_ct:eates.a,fo-0p, of imprecise g;i;}gmetfy coilsisting,oflireamiQr and the statiort gr~und bus., 'I11t'self and.~litoal. partial inductance o-f the-,armor and the:ground bus can be-:estimated usingth~:abnve;formulae.1 hµUhe'Calculatfon*'ii(not necessary"as the voJtag,e 1nd~ce~:m the armorwm raprdty'coriducrno g~c;mnd. Coupling fr<;>1n the annor to*the-ccmductor.:will be a~econd or4er-effect*-and'ihus, significh:ntlt tower than:the values cafou:fate:d above; Th'is- approach is consiste.nt'with the approach ,discussed :in GER...3205,(Refe~nce.8-:}~, 6.4 Effect of Armor
'flie control '<:abfe,anJJ.Or il gah:*anize,g;$tauil¢ss*st~e1,, '\\'~!Ch acts as a low rel~ctatice p~~ for the magnetic ,flqx due to the shortcircuit/;mment insthe medjum; voltage cable; TI1e armor (shield), ' has _the effect_of diverting-the flux awa'Y,: from lliezlow.VQltage .cot1clucto1'.~
Rosa derives:th_e self and mutuallnduetance.of conductors by, cafou1atmg.t be total H :6¢h;[ that collapses,upon,a conductor wlicna cutfont;i.u~moved from,th:at ¢onductor.(Refer.ence..9,}. *This approach includes. anSroplicit assumption thatthe.medium, of tbat conductori.i; :tmiform:
- Consideration ofthe eftect.ofaJow reluctance armor/shield. upon.the workof:.Rosaas.applied to the ONS.scenario_;friflow:s.: -
Tl1e-introduction *0£ a lowitelucta:nee steeLarmorishield.inthe,:flux fiel.d 'o f a,conducto,r has-.tlittle to no effect on. the J>ar_tial~elfinducfrtnce!q_f.a coricfuctbi\ The sliield 1vHI'fi]!ve:a liJghet fl:~. density than the.surrounding-air but:does not change the behavior of tbeH field upott' remo.vat of tµe current Namely t:hattl1efie)d collapse.s*upon tliewire in the same mann_e r~ ft~ouldiftliere werll:nQ shield ptt?sentf Sitnilariy; th:e *introduction of a-shield wilt haV<YttegligibieJmpairt. orrthe:~ partfal *mutna.l i:ridilotance.bet.ween tw9 .cond11ctors *that are bo\Jiwitliin the same .shield.- L _ _ _ _ _ __
Calculation No.; mMPR 0079-0191-CALC: ooz MPR Associates, Inc. Revision No,: O 320 King .Street Alexandria. VA 223:14 Page No;: 11 TI1e introduction of?, low reluctance steel.armor/shield in the:flux field:ofa,conductor will.affect the partial mutual inductance between two conductors. Once again .the-shield bas a higbe.r flux. density ~an the urrounding.air. However wl1en current is removed from the primacy conductor the.rumor/shield will divert flux away from the econdazy ,conductor thereby reducing the magnitude*offlux that,cQ.Jfapses upo,n the secondary ct.~tiducfor. IPR Cafoulation0079,.:0191~CALC-003, (Reference 12) estimates the effectiveness of the steel armor to shield conductors from external fields. The calculation determines that the armor reduces the fieid internaJ to the annor by a factor of approximately 9So/&' (i.e. the field .internal. to the shield is*approximately 2% of what it would be if the shield were-not present). 6.4.1 Common Mode Voltage:, With Armor Shielding The common mode voltage-in the control conductorcircu.it is the voltage induced due.to the mutual partial inductance between the mediwn voltage cable*and the return Jeg of the control cable loop. TI1e common mode voJtag~ with consideration of armor shielding effects; Vsbie.lded;JXlll1mOn, is calculated as follows~ . 2 SE:.-- *- 100 shietdtd_comr:u,n~""' SE* IV<:ommonl 6.4.2 Differential'Voltage No Armor Shielding Thecontmon mode' voltage lo the control conductor circuit is thevoltage induced due to(th:e mutual -partial inducUl,llce between the.medium voltage cable and the .return leg of the i;ontrol cable loop-. 'The common mod.e voltage :with consideration of armor shielding effectsc, V s hitldlidi,Load.:;.Ditr, js -calculated as follows:
Calculation No~:, mMPR 0079-019l;C'AI:.Cw002 MPR Associates, Inc, Revision No;:. o 320 King Street Alexandri~i-VA 22314' Page No:: 12 7 .0 REFERENe'ES
- 1. IBEE 518-1982 1EEE Guide for th/e Installation ofElectrical Equipment to Mi11.im,ize Electrical .N.oiselnputs to Controllers from &temal Sources;
- 2. Article by Cla)'forf R: Paul, PartJal'lnductance.;1 IE.EB .EMC Society Magazine, ~2Ql0.
- 3. Email from Bernard A. Norwood ONS) to Michael Katahara (MPR), Re: QUESTION ALERT - Oconee Control Cable Anafysis. Tuesday December 29, 2015 3:38PM..
- 4. Email from .Bernard::A. Norwood (ONS) to MichaelKatah_ara (MPR , Re,'. Oconee-induced:
Voltage Update. Wednesday December30;-20l5, l:57PM'. ,
- 5. Rockbestos Product peci6cation Drawing,. VC9AWG Clas.s lE JOOOV Hypalon ln:ner'
.Jacket GSJA PVC Outer Jacket Nuclear 'afetJl Related, Duke EnergyCorporaiton; Keowee Cable Upgrade. -Dated 5/09/2001.
- 6. Oconee Nuclear Specification Number OSS--139:00.-00-00lO, Keowee Underground'.
Replacement Medium Voltage Single Conductor /!owe,: Cable. Revised January ~" 2002.
- 7. Amold" Thomas and Mercier~David C., Sauthwit:e Power able Manuai~ Fourth:Edition~
8~ General Electdc: -C~ER-3205, TJteory,ofSJii:eldi'ng andGroUJ1ding ofControl Cables to-Reduce Surges. October 5 1973'.
- 9. Ro a, Edward, B, Bulletin ofthe National Bureau ofStandards, Volume 4 Number 2, the Selfand Mutual Inductances,ofLinear Conductors.
l (},, Oconee Nuclear: St~ltibn drawing:0-398-Al- l 07, Revision 1 "FSW Duetbank. Segment #7, Plan & Elevation.
- 11. Oconee Nuclear Station drawing 0-398-Al-200B Revi ion O "PSW Ductban~ Ducthank Reinforcement Sections B & C."
12~ MPRCalcufa:tion 0079-0191-CALC-003. Finite Eleme'nt Analysi.flo,Calculate Sh'ielding' Effectiveness. Revision 0. -}}