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

‘The tests have confirmed the due quality of the generator: there are no ‘bottlenecks’ in it, no cracks, shifts or punctures, and no insulation faults have been detected. That said, the insulation has due dielectric strength capacity and will foster reliable operation of the generator’, Alexander Belyaev, the chief engineer of the Leningrad NPP-2, noted.

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 unit.

Shortly, the team will continue working at the VVER-1200 2nd power unit’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. These operations are to prepare the turbine hall equipment for the key events of 2020 – the physical and the power start-up of the VVER-1200 2nd power unit of the Leningrad NPP.