ML18092B477
| ML18092B477 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 03/24/1987 |
| From: | Public Service Enterprise Group |
| To: | |
| Shared Package | |
| ML18092B474 | List: |
| References | |
| S-C-E130-CEE-01, S-C-E130-CEE-1, NUDOCS 8703310448 | |
| Download: ML18092B477 (11) | |
Text
{{#Wiki_filter:PS~G S-C-El30-CEE-0162-0 Page Date 1 of 4 1/26/87
- TITLE:
Public Service Electric and Gas Company Nuclear Department P 0. Box 236 Hancocks Bridge. New Jersey 08038 ENGG. EVAL. OF VERIFICATION AND VALIDATION OF POWER TECHNOLOGIES INC. PSS/E SOFTWARE PACKAGE AND SALEM ELECTRICAL MODEL 1.0 PURPOSE This Engineerinq Evaluation documents the verification and validation of Power Technoloqies PSS/E software package and model of *the Salem electrical system for predicting voltages during static load and transient load conditions. 2.0 SCOPE This evaluation applies to the Salem Unit No. 1 and Unit No. 2 A.C. electrical system.
3.0 REFERENCES
3.1 Salem Validation Test for Power Technologies, Inc. Computer Model, 12/13/86 3.2 Simulation Run for Validation of Salem Plant Model, prepared by L. N. Hannett, Power technologies, Inc. January 22, 1987. 4.0 DISCUSSION On August 26, 1986 an event occurred.at Salem Unit No. 2 which caused the 4KV vital buses to separate from their offsite power sources. It was discovered that a transient voltage profile study for the Salem A.C. electrical system had not been updated since June 1981. Since the last study, changes to the electrical system had been made which affect system voltages during transient conditions. PSE&G contracted Power Technologies, Inc. (PTI) to perform a transient voltaqe profile study on the Salem electrical system. After PTI developed a model of the electrical system, PSE&G proposed to use results of the model to support operating in a split bus confiquration (2 group buses aliqned to the Station Power Transformer and 2 group buses aligned to the Auxiliary Power Transformer). This configuration and study was presented to the u.s.N.R.C. for their review and concurrence since the config~ration was different from that identified in the UFSAR and justification for continued operation Safety Evaluation S-C-El30-NSE-458 Rev. 1, written after the August 26th event. The NRC ee/mpml EDD-7 FORM l REV 0 10SEPT81
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S-C-El30-CEE-0162-0 Page 2 of 4 Date: 1/26/87 questioned the validity of the model and its results since PTI
- has no formal in-house verification process
- PSE&G proposed a test to verify and validate the Salem model and the PSS/E software package. The test was performed on December 13, 1986 and consisted of logging the operational condition of all of the 4160 volt loads, location of the Station Power Transformer automatic load tap changers (ALTC), measuring the static voltage values of the 500KV grid, 4160 volt, 460 volt and 230 volt buses. The 2B vital bus was loaded with selected motors such that the motors would be operating at their brake horsepower. The loaded 2B vital bus was then swapped between the 22 and 21 Station Power Transformers. The (2) Station Power Transformers and the vital bus voltages were recorded using a Gould VRMS recorder. P.T.I was then supplied the running loads at both Salem Unit No. l and Unit No. 2, the measured 500KV grid voltage and the measured load values at the 4160/460V and 4160/230V transformers. Using this information as input to the PSS/E program and the Salem Model, PTI predicted the above test measurements for comparison.
The transfer test was performed two times. During the first 2B vital bus transfer, the Gould recorder which was being used for the No. 21 and No. 22 Station Power Transformer voltages, did not eject the paper. Although the 2B vital bus recorder did provide the expected trace, (refer to Attachment B). This trace indicated that the No. 21 Station Power Transformer started at a value of 4340 volts and since the transformer was being unloaded it should have increased in voltage. At the beginning of the next trace, the No. 21 Station Power Transfomer voltage was recorded at 4309 volts, refer to Attachment c. This difference in voltage does not agree with the recorded automatic load tap changer position in Reference 3.1, since it indicates that the tap changer never moved throughout the entire test. The automatic tap changer obviously should have moved down in tap position for the voltage to be 4309 at the beginning of the second transfer because all loads in the plant were being maintained at steady state during the test. The steady state results of the test are tabulated on Attachment A. The static measurements were taken with a Fluke 8600A Digital Multimeter that has an accuracy of .5%. The transient recordings are shown on Attachment C & D. The transient recording indicated that the No. 21 Station Power Transformer started at 4309 volts and dipped to 3964 volts after the transfer of the "B" vital bus and finally recovered to 4265 volts. The No. 22 Station Power Transformer started at a voltage of 4384 volts and increased to 4419 volts after the 2B vital bus was unloaded. The accuracy of the recorded values are +30 volts which includes the accuracy of the potential transformers and the legibility accuracy of the
- . recordings.
The initial model's predictions compared to the recorded values
- i - - - - - - - - - - - -EDD-7 -- -----1 FORM l REV 0 10SEPT81 ee/mpml
S-C-El30-CEE-0162-0 Page 3 of 4 Date: 1/26/87 indicated that the model input set points for the Station Power
- Transformers' automatic load tap changers were incorrect. This was indicated by the comparison of the recorded 4KV bus voltages (the model predictions were higher than expected) and the Station Power Transformers automatic load tap changer positions. In addition to this anomally, it was determined that the model input for the No. 22 Station Power Transformer no load turns ratio was in error.
After the model was corrected as identified above, the simulation was run again. The steady state results of the model are tabulated on Attachment A. The time simulation plot is shown on Attachment E. The No. 21 station power transformer started at a voltage of 4326 volts and dipped to 3998 volts after the transfer of the 2B vital bus and finally recovered to 4284 volts. The No. 22 Station Power Transformer started at 4383 volts and increased to 4431 volts. The recorded difference in voltage from start to full recovery for the No. 21 Station Power Transformer is a 44 volt drop as compared to the models prediction of a 42 volt drop. The No. 22 station power transformer when unloaded increased by 35 volts and the model predicted an increase of 48 volts. The maximum deviation for the transient condition as computed on Attachment F for the recorded data is 8.00% and for the model is 7.58%. During the validation process it was recognized that the automatic load tap changer could be positioned at more than only (1) tap location and still be within the control set point band. The control setpoint band width allows the Station Power Transformers secondary voltage to vary approximately 70 volts without a tap change. The 70 volt variation when put on a 4160 volt base is approximately 1.68%.
5.0 CONCLUSION
The P. T. I. Sale*m Electrical Model and PSS/E software package was able to predict the static voltages at the 460 volt and 230 volt buses at Salem Unit No. 1 and Unit No. 2 to within a difference of 1.6% of the measured values. In addition the model predicted the transient condition to a difference of .42% of the measured value. The above comparison of test results and computer model results validate the ability of the model to predict transient voltage levels within the Salem plant both during transient and static conditions. Additionally, it should be noted that when using the model for predictions the load tap changers for the Station Power Transformers should be adjusted to be just inside the control band on the low end to provide worst case data analysis.
- t-----------------l ee/mpml EDD-7 FORM 1 REV 0 l0SEPT81
S-C-El30-CEE-0162-0 Page 4 of 4 Date: 1/26/8 7 6.0 SIGNATURES
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~Group Hea SAG I Dcfte Manager -
Plant Engineering ee/mpml EDD-7 FORM l REV 0 10SEPT81
ATTACHMENT "A" INITIAL STATIC VOLTAGE VALUES Measured Models PU Value Predictions Difference % lA 460V 493 496 +.65% lA 230V 246.l 247.8 +.74% lB 460V 483 489 +l. 3% lB 230V 246 247 +.43% lC 460V 489.5 492 +.54% lC 230V 243.7 247.5 +l. 6% 2A 460V 491. 4 492 +.13% 2A 230V 247.3 247 -.13% 2B 460V 491. 2 492 +.17%
- 2B 2C 2C 230V 460V 230V 245.7 493.4 248.0 246 497 249
+.13%
+.78%
+.43%
+21 Station Power O* 1 Lower Transformer ALTC
+22 Station Power 7 Raise 7 Raise Transformer ALTC
*Should be at a lower tap position - see discussion
+Initial automatic load tap changer position when 2B vital bus transfered from 22 SPT to 21 SPT
ATTACHMENT B 2B VITAL BUS TRANSFER FROM 21 SPT TO 22 SPT I - I - I* 1-- --\ -- t- I I I - I- -I - I 1- +--I + I -I -- 1----1--+--I--+-~---+ +-t--+--1 I-* +---1----J-+--t-~+--J---'---t--' Paper Speed - 200 mm/sec Scale - 25 VAC to 125 VAC 2 Volts/mm Measuring P.T. Ratio - 35/1 NO~~: This ccpy not to scale
ATTACHMENT C 2B VITAL BUS TRANSFER FROM 22 SPT TO 21 SPT I I I I I I I 1- I I I I I I I *I-+ *I I 4309 V*JLT.S IJI I I . *\ .::: : I I I I *I I I* *l--1--1 I *+--1 -+ *-* 'J: I I I I I I I 4384 VOLTS I - I *I 'i-1**1 1-*l*I 1-1*-+--I +-+* I -+*I* I Paper Speed - 200 mm/sec NOTE: This copy not to scale Scale - 100 VAC to 125 VAC, .5 Volt/mm Measuring P.T. Ratio - 35/l
ATTACHEMENT D 2B VITAL BUS TRANSFER FROM 22 SPT TO 21 SPT I -I I -I I - I I, I I --1 1-*-t -I - I --1 I --1 -I I -I - I 1-- -I - I t*--1 1- I - -I - I --**t - I- +--1 I I I - I - -I - t--1---1---+ - I- -l--+-1----+---+ -+-+-- Paper Speed - 200 mm/sec Scale - 25 VAC to 125 VAC, 2 Volts/mm Measuring P.T. Ratio - 35/1 NOTE: This copy not to scale
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- ATTACHME1'1T "F" Test Values 4305-3964] 100 Maximum Deviation % = = 8.00%
[ 4305 [ Model 4326-399~ 100 Maximum Deviation % = 4326 - J = 7.58%
PSE&G EU;INEra.ING AND PLAN!' BEITEFMENI' lEPAR'IMENl' DESIQl VllUFICATICN R~ GMB-EMP-006
- PART A !XJCUMENTS 'IO BE VERIFIED REV *
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- r: ,1.)G.,1..,~LU~ E.VA 1..1) ATICl~
OCP/OCP I'll. <Ir AfPL. l
\='cwi:-& Tec..t! r~ E.LEe... Mo~J CAb{lJ~IZI Al~ EvAwA-n 1J .J EL/I&C: ~ STRlJCr:
DISCIPLINE(S): M&:H: 00~ 1HIS DESIQl cx:Nl'AIN A.5SUMPI'IONS REJ;lUIRING INPUI' IXX:UMENTS RE.V. I.ATER ~FIRMATION? _ _YES ~00
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SI~TURE
~ * ~~e2 TE PART B Assigned By:
Verifier Assigned (Print) Date PART C MEniOD OF VERIFICATIOO EXTlliT OF VERIFICATIOO O Design Review/!Xleument Review []. Identical to Previously Verified oesiyn (Identify) D Alternate Calculation D ::;imilar to Previously Verified Design (Identify) D Qualification Testina D New (no identical or similar desian) FOR IT~ VERII:'IED BY DE::iIGN REVIE.W, om::K ~~. "YES," "00," CR "N/A" IF f'Ul' APPLICABLE. PROVIDE ADDITIONAL (l)l>l-l.ENl'S, IF NEEDED, IN PARI' E. SEE RE.VERSE SIDE FOR COMPLETE QUESTIOO. YE::; 00 N/A YES NJ N/A DE::;IGN REV! Eli QU~'TIOOS RlliruNSE DESIGN REVIEW QUESTIOO::; RESPONSE
- 1. Appropriate design input? 10
- Material Ccmpatibility
- 11. Maint. Reqnts. Accessibility
- 2. Adequacy of Assumptions?
- 12. I::;I Requirements?
- 3. QA Requirements?
- 13. Radiation Protection?
- 4. Codes, starrlards, regulatory requirements? 14. Inclusion of Acceptance Criteria?
- s. Construction and Uperatirq 15. Test Requirements experiences?
- 16. Handlin;i, Stora;ie, Cleanin;i and
- 6. Design Interface Requirements? Shippin;i Requireme~~s?
- 7. Appropriate Design Method? 17. Identification ReqLirements?
- 8. Reasonable 0-ltput? 18. Recore Preparation, ~eview Approval and Reten~~on
- 9. Proper Canponent Application? Requirements?
PART overifier attests to bein;i independent of the desiyn eftort identified in Part "A" (!Xleuments to be verified). verifier further attests that all a::rmients regardin;i the design effort have been resolved and that the document is verified. ':erifier Signature Date PART E (Use additional sheets if required)
- GMB-EMP-006 Exhibit l (Rev. 1 NED/5 12*-13 Paqe l of 2 Rev. l}}