INES-event
INES 0

UNIT SCRAM DUE TO SHORT-TIME DEENERGIZATION OF AUXILIARY POWER BUSES

The unit was operating at 58% of nominal power. At 05:45 as a result of a thunderstorm disconnection of the 330 kV transmission line and opening of oil breaker of one of the two turbine generators occurred. In the course of automatic changeover (to feed the 6 kV auxiliary power buses from standby source) AZ-1 emergency protection (scram) actuated due to mismatch between the time for automatic changeover and time delay for AZ1 protection actuation. The remaining protections, controls and safety systems actuated as designed. Breach of limiting conditions of operation did not occur.

Location: KOLA-1
Event date: Wed, 12-08-1992
Nuclear event report
Legenda & explanation