High-voltage tests delivered at the Leningrad NPP

02 June 2020

High-voltage generator testing has been successfully delivered at the turbine hall of the Leningrad NPP VVER-1200 2nd power block: the team verified the winding insulation with an alternating potential of 36 kV. This is one and a half times higher than the generator’s working voltage.

High-voltage tests were completed within one shift. Each of the six phases took one minute. This time was enough to detect all possible insulation defects. A longer exposure might lead to the destruction of the insulation under test, even if it has no defects.

To support generator winding’s insulating properties at the necessary level and to foster reliable operation of the equipment throughout its designed life span (50 years), high-voltage insulating tests will be carried out every four years. The preventive inspections will be combined with major renovations at the power block.

Shortly, the team will continue working at the VVER-1200 2nd power block’s turbine generator: they will place the rotor into the stator, lay out the turbine shafting, and finalize the installation of the turbine onto the engine-turning gear.