ML17340A512

Forwards Addl Info Re Distribution Sys Voltages,In Response to NRC 800819 Ltr.Since Safety Injection Signal Initiates Automatic Fast Transfer from Auxiliary Transformer to Startup Transformer,Only Connection Via Startup Analyzed

ML17340A512
Person / Time
Site:	Turkey Point
Issue date:	12/18/1980
From:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
To:	Varga S Office of Nuclear Reactor Regulation
References
L-80-411, NUDOCS 8012240430
Download: ML17340A512 (28)

Text

REGULA'RY INFORMATION'DISTRIBUTI SYSTEM (RIDSi ACC)SS ION NBR".80 1'2240430 DOC~DATE: 80/12/18 NOTARIZED; NO DOCKET FA$'fL:50-250 Turkey Point Pl anti Uni t 3R Fl or ida Power and Light C S0-2S1 Turkey Point Planti Unit 4E Florida Power and Light'C AUTH BYNAME AUTHOR AFFILIATION UHRIGER.E.

Florida Power 8 Light Co.RECI'P~NAME RECIPIENT AFFILIATION VARGApS,A,~.Operating Reactors Branch 1

SUBJECT:

Forwards addi info re distribution sys vol tagesiin response to NRC 800819 1 tr.Since safety injection signal initiates automatic fast transfer from auxiliary transformer to startup transformer<only connection via startup anal.yzed, DISTRIBUTION CODE: AO IBS COPIES:RECEIVED:LTR ENCL SIZE:~'P~~TITLE: Onsite Emergency Power Systems NOTES: RECIPIENT Io CODE/NAME ACTION: VARGA:E S~04 INTERNAL: AEOD I8,C SYS BR 09 MPA 18 OELD 17 OR A SS BR 12 tR F ILt 01 COPIES LTTR ENCL 7 7 1 1 1 1 1 1 1 1 1 1 1 RECIPIENT ID CODE/NAME GEN ISSUES BR13 I 8'E 06 NRC PDR 02 OP EX EVAL BRil POlt(ER SYS BR 14 COPIES LTTR ENC'L 1 1 2 2 1 1 1 1 1 1 EXTERNAL: ACRS NSIC 16 05 ib 16 1 1 LPDR 03'0 80 logy TOTAL NUMBER OF COPIES REQUIRED: LTTR 37 ENCL 37 FLORIDA POWER da LIGHT COMPANY December 18, 1980 L-80-411 Office of Nuclear Reactor Regulation Attention:..Mr S.A.Varga, Chief Operating Reactors Branch IIIl Division of Operating Reactors U.S.Nuclear Regulatory Commission.Washington, D.C.20555

Dear Mr-Varga:

Re:.Turkey Points'Units 3 8 4 Docket Nos.50-250.8 50-251 Adequacy of Station, Distribution S stem Volta es Florida'Power 8 Light Company's response to a NRC letter dated August 19, 1980, requesting additional information on the above subject is attached.Very truly yours, Robert E.Uhrig Vice President Advanced Systems 8 Technology REU/PLP/ras Attachment cc: J.P.O'Reilly, Region II Harold F.Reis, Esquire ll3i<'e'8'I 833lh83SHOll.":

"'J 38N SA Lf%5 53";fh%:.tsol~ASi BESlQ G3AY~333 PEOPLE...SERVING PEOPLE I'n response to NRC letter to FPL dated August 19, 1980 Y], e: Request for Additional Information, Tux'key Point Units 3&4 Adequacy of Station Electric Distribution System (dated July 1, 1980)

Reference:

1)NRC letter to FPL dated August 8, 1979 2)FPL letter to NRC dated November 9, 1979 This response addresses the NRC's request for Additional Information enclosed in the NRC letter to FPL dated August 9, 1980.Clarification of.assumptions and specific voltage analysis results are provided herein.Also provided is information requested concerning loading configurations that require greater than the minimum expected steady-state grid voltage in order to start all safety loads simultaneously.

Guideline 1 (Reference 1)requires that separate voltage analyses be performed, for each connection to offsite power"...assuming the need for electric power is initiated by (1)an anticipated transient (e.g.unit trip)or (2)an accident, whichever presents the largest load demand situation." At Turkey Point, the largest load demand situation occurs under an accident condition wherein a safety injection signal starts all safety loads simultaneously.

In accordance with Guidelines 3 and 5, all automatic actions by the electrical system are assumed to occur as designed.Therefore, since a safety injection signal initiates an automatic fast transfer'from the auxiliary transformer to the start-up transformer, only the connection to offsite power via the start-up transformer was analyzed.In order to obviate the need to repeatedly calculate the voltage at the terminals of each safety load for each case analyzed, as implied by Guidelines 6 and 7 (Reference 1), FPL chose to calculate the minimum voltage at each bus required to start each safety load.The highest minimum required voltages calculated for each bus are listed in Attachment A.If the voltage analysis results (above)are higher than those minimum values, then sufficient voltage would exist at the terminals of all safety loads to assure their successful start.The requirements of Guideline 6 (Reference 1)were addressed in the second and third paragraph of page 2 of our November 9, 1979 response (Reference 2).As stated therein, the minimum expected steady-state grid voltage at Turkey Point is 235 KV and the maximum is 244 KV.All low vol'tage AC (less than 480V)Class IE busses supplying power to vital instrument or control circuits at Turkey Point are powered by inverters supplied from the 125 VDC batteries.

Being independent of offsite power, these busses are not included in the voltage analyses.The heat tracing system is the only safety related equipment powered from busses less than 480V.Since the heat tracing is a purely resistive load, voltage variations vill affect the heat output of the system.llowever, the voltages calculated in the analyses provided herein will have little or no effect on the performance of the heat tracing system because the voltages resulting from these.analyses are the worst momentary voltages that could occur upon start of all safety loads simultaneously.

As the starting motors accelerate, the voltages would increase.On this basis, voltage variations due to motors starting is not considered to have any adverse impact on Class IE equipment powered from busses less than 480V.

though Turkey Point is a multi-unit station, the voltages analysis suggested by Guideline 2 (Reference 1)was not performed since the connections to offsite power for Units 3 and 4 are independent of each other and would, therefore, not be different from those provided herein.In addition to the assumptions contained in the above discussion, the five assumptions listed in our November 9, 1979 response (Reference 2)apply to all cases analyzed.Also, in all cases, no manual load shedding was assumed.In accordance with Guidelines 3 and 5, tripping of the Steam Generator Feedwater Pumps was assumed since this occurs automatically on a Safety Injection Signal.Unique assumptions for each case analyzed involve which Condensate Pumps, Component Cooling Water Pumps, and Intake Cooling Water Pumps are assumed running at the time of the accidents Two out of three of each of these pumps are normally running, but only the A and B pumps receive a start signal on safety injection actuation.

This results in various combinations of starting and running loads as reflected in Attachment B.Attachment C provides the results of the voltage analyses for each case on each unit.In order to provide assurance that no safety loads could experience excessive voltage (Guideline ll, Reference 1)calculations were performed assuming one-half normal load on the 480V busses, minimum pumps running on the 4KV busses, and maximum voltage (244KV)on the grid.The results are presented in Attachment D.Since no calculated voltage is in excesses of 10%of the equipment nameplate (460V or 4000V), the results are considered satisfactory.

In accordance with the subject NRC Request, additional voltage analyses were performed assuming all safety loads have started and are running, and the largest non-Class IE motor is started.(Motor operated valves are assumed to have completed their action}~Because the 7000 HP Steam Generator Feedwater Pumps are tripped off on a Safety Injection Signal, it is possible that an operator could re-start a pump after the safety loads are running (although such action in not per procedure) and is not required for safe shutdown).

Only two cases for each unit were analyzed: Case 2 (Attachment B), which results in the highest load on the"A" train, was assumed when starting the"A" Steam Generator Feed-water Pump.Case 13 (Attachment B)which results in the highest load on the"B" train, was assumed when starting the"B" Steam Generator Feedwater Pump.The results of these analyses are tabulated in Attachment E.Also tabulated are the bus voltages required to maintain minimum guaranteed starting voltages at the running safety equipment terminals.(These voltages are based on voltage drops due to full load current.Attachment A voltages are based on voltage drops due to starting currents).

Only in the case where the 38 Steam Generator Feedwater Pump is started does an analyzed voltage fall below the required voltage.In this case, HCCD is less than 1.8.volts low.Since the equipment is capable of starting and running at the required voltage, it is reasonable to assume that running equipment will continue to run at the analyzed voltage during the starting of the Steam Generator Feedwater Pump.In any event, the voltages do not decrease sufficiently to cause starters or contactors to drop out.On this basis, the results of these analyses are considered satisfactory.

1;)order to verify the accuracy of the voltage analyses, voltage and current measurements were made at all Class IE busses.A voltage analyses was then performed using the measured loads and'he resulting voltages compared with the measured voltages.The close correlation between the measured and calculated values (less than 3%difference) provides assurance that the mathematical model used in the voltage analyses is accurate.In response to Items 5 and 6 of the subject NRC request for Additional Information, the loading configurations that require greater than the cases 13 and 14 in Attachment 8 and result in the calculated'us voltages provided for those cases in Attachment C for Unit 3 only.The operators at Turkey Point have been instructed to avoid operation under these loading configurations.

If, due to equipment malfunction, the plant is required to be operated in one of these configurations, the operators have been instructed to ensure that the switch-yard voltage remains above that.which analyses indicate is sufficient to safely start all safety equipment.

If, while operating in one of these loading configurations, the switchyard voltage decreases below the analyzed safe voltage for, that configuration, the operators are instructed to,decrease the unit's output and thus lower the demand on the electrical system.Such"reduction of loading" as quoted in Item 6 of the subject:NRC request does not imply manual load shedding in that no motor or, equipment is shutdown,.

The reduction of load on the electrical auxiliary system is due to lower power required by the various process pumps in the plant.However, as stated in our letter of November 9, 1980, a design modification is in progress,to add undervoltage relay protection to the 4160V and 480V load center.This modification, will eliminate the need for administrative restrictions on operation of the plant.In response to Item 4 of the subject NRC request, please refer to our response to NRC letter to FPL dated July 26, 1979 attached to FPL letter to NRC dated November 9, 1979 (Reference 2).The review requested by Item 2 of the subject NRC request is contained in Chapter 8 of the Turkey Point FSAR.

A tachment A HIGHEST iilININUll VOLTAGES RE UIRED TO START SAFETY LOADS Page 1 of 1 Unit 3 4KV Bus 3A 4KV Bus 3B 480V Load Center 3A 480V Load Center 3B 480V Load Center 3C 480V Load Center 3D 480V HCC 3A 480V iICC 3B 480V i~lCC 3C 480V>jcc 3D.3214.4V 3213.5V None starting None starting None starting None starting 381.4V 392.2V 399.9V 398.3v Unit 4 4KV Bus 4A 4KV Bus 4B 480V Load Center 4A 480V Load Center 4B 480V Load Center 4C.480V.Load Center 4D 480V>1CC 4A 480V i~lCC'4B 480V;lCC 4C'215.8V 3213.4V None starting None starting None starting None starting 402.9V 396.7V 393.1V Attachment B L ADING CONFIGURATIOiVS Page 1 of 1 In all loading configuration cases listed below, the Safety Injection Pumps and RHR Pumps (1 each per 4KV bus)are assumed to start and the Heater Drain Pumps (1 per bus), Turbine Plant Cooling Mater Pumps (1 per bus), circulating Mater Pumps (2 per bus), and the Reactor Coolant Pumps (1 on A bus, 2 on B bus)are assumed to be running.The Steam Generator Feedwaeer Pumps are tripped off upon Safeey Injection Signal.The running and starting loads on the 480V load centers and motor conerol centers do not vary between, cases analyzed.The cases listed below apply equally to Unit 3 and Unit 4.Case Condensate Pumps+Comp.Cooling Water Pumps+A B C B~: C Intake Cooling Water Pumps+Ai'i'c'OFF RUN RUN START RUN RUN START',.,.:,.RUN,!;,RUN,.;,.RUiV OFF RUN START RUN RUN START RUN RUN OFF RUiN RUN RUN START RUVi START RUN RUN RUN OFF RUN RUVi START RUN START RUN RUN OFF RUN RUN OFF RUN RUiN RUN RUN RUN RUN OFF OFF START START RUN RUN RUN RUiV 10 OFF RUN OFF RUN OFF RUN OFF RUiV OFF RUN RUiV RUiV RUN RUiN START START RUN RUiV RUN RUiN RUN START START RUN RUiV RUN RUN RUN OFF RUN RUN RUN RUN RUN START RUiV START RUN START RUN START RUN START RUN 12 14 16 18 RUN OFF RUN OFF RUVi OFF RUN OFF RUN OFF RUiV OFF RUN OFF RUiV RUiV RUN RUN RUN RUiV RUiV RUN'TART START'UN RUiV RUN RUN RUiV RUN RUN START START RUiV RUiN OFF RUN RUN RUN RUN OFF OFF RUiV RUN RUN RUN RUN RUN RUN START RUN RUiV RUN RUN RUiV RUiV RUiV OFF OFF OFF OFF OFF OFF+Two out of three normally running Pumps start automatically on S.I.S.if not already running.

Attachment C Page 1 of 18 VOLTAGE ANALYSIS RESULTS CASE 1 UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235'V)4KV Bus A*01 4KV Bus A**q q.s8tq 4KV Bus B'+4KV Bus B:"~480V LC A 480V LC B'80V LC C 480V LC D 480V NCC A 480V/ICC B'80V NCC C 480V NCC D 3851 432 422 419 430 430 403 407 405 3861 417 423 432 428 430~High-side of current limiting reactor**Low-side, of current limiting reactor+Not on Unit 4 Attachment C Page 2 of 18 VOLTAGE ANALYSIS RESULTS CASE 2 UNIT 3'k UNIT 4 BUS VOLTAGES (Grid at 235 KV)4KV Bus A*4KV Bus A**.i 4KV Bus B*4KV Bus B**480V LC A 480V LC B 480V LC C 3 03 3786 3944 3876 429 425 416 38 8 3781 3953 3888 415 426 F, 480V LC D 433 432 480V HCC A 480V HCC B 480V'CC C 480V'?ICC D 427 406 404 409 408 418 427<<High-side of current limiting reactor**Low-side.

of current limiting reactor+Not on Unit 4 Attachment C Page 3 of 18 VOLTAGE ANALYSIS RESULTS CASE 3 UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235 KV)4KV Bus A*4'us A**4KV Bus B*4KV Bus B**480V LC A 3953 3864 3894 3797 438 3951 3862 3901 3807 480V LC B 480V LC C 480V LC D 480V Mcc A 42 423 436 4 422 480V MCC B 480V>>CC C 480V MCC D 397 413 399 409 436*High-side of current limiting reactor**Zaw-side of current limiting reactor~+Not on Unit 4 Attachment C Page 4 of 18 VOLTAGE ANALYSIS RESULTS cAsE 4 UNIT 3 UNIT 4 BUS VOLTAGES (Grid at,235 KV)4KV, Bus A*4KV Bus A**3 36 3839 3837 4KV Bus B*4KV Bus B**480V L'A 480V LC B 480V LC C 3913 3823 435 419 422 3919 3833 421 420 436 480V LC D 480V'CC A 480V HCC B 433 400 4 412 480V HCC C 480V HCC D 410 402 433*High-side of current limiting reactor**Low-side.

of current limiting reactor+Not on Unit 4 Attachment C Page 5 of 18 VOLTAGE ANALYSIS RESULTS cASE 5 UNZT 3 UNIT 4 BUS VOLTSXKS (Grid at 235 KV)4KV Bus A*4'us A**4KV Bus B*4KV Bus B**480V LC A 480V LC B 480V LC C 480V LC D 48OV IICC A 480V NCC B 480V HCC C 3872 3931 3855 439 423 426 43o 437 4o4 414 387o 3939 3865 425 423 44o 428 418 q+~~jul gu ee'~P)p I 480V i~ICC D 4o6*High-side of current limiting reactor**low-side, of current limiting reactor+Not on Unit 4 Attachment C Page 6 of 18 VOLTAGE ANALYSIS RESULTS CASE 6 UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235 KV)4KV Bus A*4KV Bus A**4KV Bus B*'KV Bus B~*.480V LC A 480V LC B 480V LC C 3 43 3847 3948 3880 436 426 423 3 40 3844>>>>}'957 3892 422 426%>>k)<}r 4/>>'}~>>-(>>~~480V LC D 4S2 480V MCC A 480V MCC B 434 406 415 418 480V MCC C 480V MCC D 409*Efigh-side of current limiting reactor**Low-side. of current limiting reactor+Not on Unit 4 Attachment C VOLTAGE ANALYSIS RESULTS CASE 7 UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235 KV)4KV Bus A*4KV Bus A**3853 38 o 4KV Bus B*4KV Bus B**480V LC A 480V LC B 3901 3809 437 418 3818 422'18 480V LC C 480V LC D 480V HCC A 480V HCC B 480V HCC C 480V HCC D 425 435 398 411 4oo 423 416 41o 435~High-side of current limiting reactor'**Low-side, of current limiting reactor+Not on Unit 4 Attachment C Page 8 of 18 VOLTAGE ANALYSIS RESULTS CASE 8 UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235 ZV)4KV Bus A*4KV Bus A**4KV Bus B*4KV Bus B*~480V LC A 480V LC B 480V LC C 480V LC D 480V MCC A 480V MCC B 480V MCC C 480V MCC D 3827 3918 3834 42o 421 428 432 4ol 409 4o4 824~(Vv'3 26 384'2o 421 43C?427 413 413 432 1~V p,?r p q'*High-side of current limiting reactor"*Low-side. of current limiting reactor+Not on Unit 4 Attachment C Page 9 of 18 VOLTAGE ANALYSIS RESULTS CASE UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235'V)4KV Bus A*4KV Bus A**4KV Bus B*3 o6 3867-78 3905/'ll%(gA;~1A'.;F 0 f)Cwf~~$4g')h)+pl)l",(i i~II'3874 4KV Bus B~*480V LC A 480V LC B 3755 411 3764 429 480V LC C 480V LC D 480V NCC A 4 41 441 4a 422 480V HCC B 3 2 4o4 480V NCC C 480V lICC D 394 441*High-side of current limiting reactor**Low-side, of current limiting.reactor+Not on Unit 4 Attachment C P~e 10 of 18 VOLTAGE AHALYSIS RESULTS CASE 10 UNIT 3 U!NIT 4 BUS VOLTAGES (Grid at 235'V)4KV Bus A*4KV Bus A**4KV Bus B*4KV Bus B."" 480V LC A 480V LC B 480V LC C 480V LC D 480V HCC A 480V NCC B 480V HCC C 3881 3884 3780 440 427 422 438 395 3880 3892 3790 426 415 420 407 438 I 4@i yW t W'V~<<g r>f~)'W le~q a~480V IICC D 397*High-side of current limiting reactor<*Zow-side of current limiting reactor+Not on Unit 4 'E Attachment C Page 11 of 18 VOLTAGE ANALYSIS RESULTS CASE ll UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235Ã1)4KV Bus A*4'us A**4KV Bus'3*o 4/i~p~~'I Ro12"'4 i~i~'li~1~~Q s g', p P log%I 1 4471 Bus B*" 3812 3822 480V LC A 480V LC B 480V LC C 480V LC D 480V'HCC A 480V HCC B 480V HCC C 480V HCC D 418 431 425 442 399 418 401 429 419 423 423 411 442\~Eiigh-side of current limiting reactor**Low-side. of current limiting eactor+Not on Unit 4 Attachment C Page 12 of 18 VOLTAGE ANALYSIS RESULTS CASE 12 UNIT 3 UNIT 4 BUS VOLTAGES (Grid't 235 KV)4KV Bus A*4KV Bus A**4KV Bus B*3922 4)1)1(4$~Alp~J)&tggl~gf'kJ~F'J'4KV Bus B**480V LC A 480V LC B 480V LC C 480V LC D 480V MCC A 480V MCC B 480V MCC C 3838 441 421 428 429 439 4ol 416 q84 427 421 442 427 42o 413 43'80V MCC D 404*High-side of current limiting reactor~*Low-side of current limiting reactor+Not on Unit 4 Attachment C Page 13 of 18 VOLTAGE ANALYSIS RESULTS CASE 13 UNIT 3 UNIT 4 BUS VOLTAGES (Gria at 235 KV)4KV Bus A*4KV Bus A**3949.3856 3945 3852 4KV Bus B*4KV Bus B**480V LC A 480V LC B 480V LC C 480V LC D 480V 11CC A 480V ailCC B 480V NCC C 480V NCC D 3933 3857 423 431.435 404 412 406 3941 3868 423 438 429 416 416*High-side of current limiting reactor**Low-side of current lim'ting reactor+Not on Unit 4 0 Attachment C Page 14 of 18 VOLTAGE ANALYSIS RESULTS CASE 14 UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 235 KV)4KV Bus A*4KV Bus A**4KV Bus B*4KV Bus B**480V LC A 480V LC B 480V LC C 4SOV LC D 480V lICC A 480V HCC B 480V lICC C 480V lICC D 383o.3950 3883 434 426 421 434'32 4oY 409 41o 3827 1 il I~w g y g~-'3959 3895 42o 427 435'432'13 419 432'I*High-side of current limiting reactor**low-side. of current limiting reactor'Not on Unit 4 Attachment C Page 15 of 18 VOLTAGE ANALYS IS RESULTS CASE 15 UNIT 3 UNIT 4 BUS VOLT&DES (Grid at 235'V)4KV Bus A*4KV Bus A**4'us B*4):V Bus B."*480V LC A 480V LC B 480V LC C 480V LC D 480V NCC A 480V HCC B 480V i~ICC C 480V HCC D 3982 3909 3899 3803 443 43P'424 398 418 400 3 81 3908 il<i<P<<'<P<t~i~l w~<~, P<?I~<<<'<3906 3813 429 417 423 422 41P*High-side of current limiting reactor**m~N-side.of current limiting reactor+Not on Unit 4 Attachment C Page 16 of 18 VOLTAGE ANALYSIS RESULTS.CASE 16 UNIT 3 UNIT 4 BUS VOLTE~(Grid at 235 KV)4KV Bus A*4KV Bus A**4KV Bus B*4KV Bus B~*480V LC A 480V LC B 480V LC C 480V LC D 480V MCC A 480V NCC B 480V NCC C 480V HCC D 3883" 3916-3828 440 42o 428" 428 438 4oo 415 4o3 3882)f~3924 384o 426 42o.441426 42o 412 439 I~~,"r'~l&l~Vigol~(1'4(i t (%~I*High-side of current limiting reactor**Low-side. of current limiting.reactor+Not on Unit 4 Attachment C Page 17 of 18 VOLTAGE ANALYSIS RESULTS CASE 17 UNIT 3'UNIT 4 BUS VOLTAGES (Grid at 235 KV)4KV Bus A*4KV Bus A**4KV Bus B'>>3 1 3936 16 3 44 4KV Bus B**3861.3871 480V LC A 480V LC B 480V LC C 480V LC D 480V NCC A 480V HCC B 480V iXCC C 431 431 404 419 430'445 4z9 423, 442 480V NCC D 407*High-side of current limiting reactor**Le~-side, of current limiting reactor+Not on Unit 4 Attachment C Page 18 of 18 VOLTAGE ANALYSIS RESULTS CASE 18 UNIT 3 lJNIT 4 BUS VOLTAGES (Grid at 235'V)4KV Bus A*4KV Bus A**4KV Bus B*4KV Bus B"*480V LC A 480V LC B 480V LC C 480V LC D 480V hlcc A 480V-hlCC B 48OV hlCC C 480V hlcc D 3 2 3891 3953 3887 441 426 428 435 439 4o7 416 41o s 6 3890 3962 3898 427 427 442 433 42o 419 439*High-side of current limiting reactor**Low-side. of current limiting reactor+Not on Unit 4 Attachment D Page 1 of 1 VOLTAGE ANALYSIS RESULTS ASSPiflifG lfINIBIUi~f LOAD&MXI!'fUi~f SWITCHYARD VOLTAGE UNIT 3 UNIT 4 BUS VOLTAGES (Grid at 244 KV)4KV Bus A*4326 4326 4KV Bus A**4KV Bus B*4KV Bus B**480V LC A 480V LC B 480V LC C 480V LC D 480V HCC A 480V HCC B 480V HCC C 4312 4325 4311 494 494 F06 493 491 493 4312 4328 494 494 494 498 493 493 493 480V l1CC D 500*ffigh-side of current limiting reactor**Low-side of current limiting reactor+Not on Unit 4 Page 1 of 2~'OL~AG-hN" L~STS B" SUL'-Uil"" 3 ASSU?~iING SAFE'Y LOAD HUlli?ZNG AllD STAR ZNG OF LARGEST llOH-CLASS lE LOAD BUS VOL~KG=S (Gr'd at 235 KV)BUS REQUIRED CASE 2 CASE 13~5 A IW 4-'qt"'Vi Bus 3'0;l:80V')~8Pq~C rs 48"V..C D NONE 32O4 NONE 32O4 38O NONE 3537 34 2 3 82 3 3 448 3 6 4 6 4OO8 3 70 35O4 346~33 480V:!".C NONE 44o 48OV:'CC 48Or i:.CC C 48O'!iiCC D 86 442 442*bligh-side of current limiting reactor**.-'Low-side of current limiting reactor Att"chment E Page 2 of 2 VOLTAGE ANALYSiS B" SULTS-UIIIT-", ASSUMING SAFETY OADS BUNNZNG AIID STABTiNG OF LARGEST HON-CLASS IE LOAD BUS VOLTP GES (Grid at 2 g Kv)4'us A'"'KV Bus A~~4I:V Bus B~4kÃBus B-+480V LC A REQUIRED Nol'1E.3203 NONE 32o4 CASH 2 8 3474'4 3968 393'CAS" 13 s~~<~4'7 3go6 4 2 4zo 48OV LC B 480V LC C 48ov LC D NONE 4co 4 6 48ov:.cc A'88 44 48ov I.ICC B 40ov I:cc c NOPE 4*High-side of current limiting reactor>>'Low-side of current 1initing reactor}}