According to the information of Energoatom, the operator of nuclear power plants (NPPs) of Ukraine, on November 28, 2014, at 19.24, reactor unit № 3 of Zaporizhia NPP was disconnected from power network by the fault protection system of its generator. The reason of its disconnection was the damage to the coil of the voltage transformer of the unit’s internal power supply section. This damage caused the shutdown of both the transformer of the unit’s internal power supply and of the switches of the unit’s main transformer.
Automatic fault protection system worked according to the established operation algorithm. The unit was put into cold operational mode without any problems. There has been no radiation impact. Preliminary assessment of the level of the event by the international scale of nuclear accidents INES: lower than the scale register / «0» level.
The unit’s internal power supply is now being restored. According to the restoration works schedule, the unit is to be reconnected to the power network on December 5.