ML19254D089

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Responds to IE Bulletin 79-23, Potential Failure of Emergency Diesel Generator Field Exciter Transformer. Submits Data Illustrating Extensive Testing of Both Diesel Generators Prior to Startup
ML19254D089
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 10/08/1979
From: Wachter L
NORTHERN STATES POWER CO.
To: James Keppler
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 7910220358
Download: ML19254D089 (2)


Text

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MSP NORTHERN STATES POWER COMPANY MIN N E A PO Li e. MIN N E 5 0 fA 55408 October 8, 1979

Mr. James G. Keppler Director - Region III Office of Inspection and Enforcement United States Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

PRAIRIE ISLAND NUCLEAR GENERATING PLAh"r Dockets No. 50-282 and No. 50-306 The following is in response to IE Bulletin 79-23:

1. The following data applies to emergency diesel generators installed at Prairie Island:

Number of Units - 2 Diesel Manufacturer - Fairbanks Morse Model - 38 TD 8-1/8 Generator Manufacturer - Fairbanks Morse Type - TG2J Frame - 956-34 Rating - 3000 KW (Continuous) 3250 KW (30 Minutes) 3 phase, 60 Hz, 900 rpm

.8 pf, 4160V, 3750 KVA Static Exciter & Voltage Regulator

. Manufacturer - Basler Electric Co

~. Model - SBHV Rating - 2740 KW 0.8 pf, 4160V, 60 Hz FLA 65 amps at 0.8 pf

}l9 i 791022o 3 E 8 OCT 111979

/

NORTHERN STATES POWER COMPANY

" Mr. James G. Keppler

  • October 8, 1979 Page 2
2. Field current for these generators is developed from the vector summation of the outputs of three current transformers, each in series with one phase of generation output, and three saturable transformers star connected across the generator output. The neutral of the saturable transformer is floating. Therefore, the problem described in IE Bulletin 79-23 does not exist at Prairie Island.
3. Both diesel generators at Prairie Island were subjected to extensive testing prio- to startup as illustrated by the following table. No excursions beyond the design limits of the diesel generators were experienced during full load and overload tests.

D1 D2 Hours running 337 337 Hours at full load 55 (including 49 53 (including 35 consecutive hours) consecutive hours)

Hours at 1/2 hr rating 1/2 1/2 Yours very truly, L. J . achter Vice President - Power Production and System Operation cc: Mr. G. Charnoff NRC Office of Inspection and Enforcement Washington, D.C.

i195 345

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