PNO-III-85-064, on 850725,low Voltage Station Auxiliary Transformer Tripped,Causing Loss of Power to Safeguard Buses.Caused by Wet Pressure Relay

PNO-III-85-064:on 850725,low Voltage Station Auxiliary Transformer Tripped,Causing Loss of Power to Safeguard Buses.Caused by Wet Pressure Relay

ML20126L215
Person / Time
Site:	Point Beach
Issue date:	07/25/1985
From:	Chrissotimos N, Jackiw I NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
References
PNO-III-85-064, PNO-III-85-64, NUDOCS 8507310113
Download: ML20126L215 (1)

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PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PN0-III-85-64 Date July 25, 1985 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without veri-fication or evaluation, and is basically all that is known by the staff on this date.

Facility: Wisconsin Electric Power Licensee Emergency Classification:

Point Beach Unit 1 XX Notification of an Unusual Event Two Rivers, WI 54241 Alert Site Area Emergency Docket No: 50-266 General Emergency (g Not Applicable

Subject:

LOSS OF POWER TO SAFEGUARD BUSES At6:04a.m.,(CDT), July 25, 1985, the station's Low Voltage Station Auxiliary Transformer (LVSAT) tripped causing a loss of power to the Unit 1 safeguard buses. Both emergency diesel generators automatically started to provide power to the safeguard buses (Power also could have been supplied to the safeguard buses via cross-tie to Unit 2, which was unaffected by the transformer trip).

The licensee declared an unusual event at 6:25 a.m. (CDT), in accordance with its emergency procedures and commenced shutting down.

Tha cause of the transformer trip was attributed by the licensee to a pressure relay that had btcome wet during a rainstorm. The relay problem was later corrected and the transformer restored to operating condition. The unusual event was terminated at 9:13 a.m. (CDT) and the unit was returned to full power.

During the event, the resident inspector was in the control room monitoring licensee activities.

Th2 State of Wisconsin will be notified.

Tha Headquarters duty officer was first notified of this event at 6:37 a.m. (CDT),

July 25, 1985. This information is current as of 3 p.m. (CDT), July ~25, 1985.

CONTACT: NuNb I. Jac hCS

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