Microprocessor-based diagnostic device for protecting the generator-transformer unit from a single-phase ground fault

1. A microprocessor-based device was developed for checking (measuring) the level of the insulation resistance of the stator winding of a unit in the range 0.5–500 MΩ and absorption coefficient in the range 1–10 with output of the measurement results to a digital indicator. 2. All measurements are taken on a stopped or operating unit in a semiautomatic regime after pushing a button on the face panel of the device. It is possible to use the device as part of a process control system or in a diagnostic system with automatic control from a computer. 3. The device underwent a check on the units of the Skhodnya and Chirkey hydrostations, where it showed good results. It is suggested that it be introduced.