Field detection of ultra-wideband partial discharge of generator stator insulation

The stator winding insulation is the important part of a large generator. The stability of its service depends on the performance of stator winding insulation. The characteristics of partial discharge of 300 MW, 18 kV turbo-generator stator insulation in Yaomeng Power Plant Co. Ltd of China are studied by the developed ultra-wideband (UWB) partial discharge measurement system. The characteristics of partial discharge in the bus room, the ground-wire room and the end of excitation are studied. The partial discharge signals can be detected correctly and sensitively in these three places. The interfering signals are detected in the field too. The PD signals and the interfering signals are analyzed in the time domain and the frequency domain. The result shows that the characteristics of time-domain and frequency-domain depend on the position of partial discharge signals. It is useful for UWB partial discharge detection to be used in field test.