Partial discharge influence on dissipation factor values during stator-bar testing

The article investigates how partial discharge activity can influence dissipation factor values in stator-bar testing. In this study, the PD phenomenon was simulated as a process composed of periodic positive and negative bursts of PD pulses over a period T of the applied voltage (frequency = 50 Hz, T 20 ms in this work). These periodic pulses generate a frequency spectrum whose fundamental frequency (50 Hz) can interfere with DF values while DF values are measured at the same frequency. An artificial defect was made on a virgin stator bar to generate PD signals. Both the simulated and real PD signals recorded from the bar at various voltage levels were studied, and the parameters of PD signals that influence the DF values were investigated.