Simulation on propagation of partial discharge pulses in transformer windings

The propagation of partial discharge (PD) pulses in transformers is greatly influenced by their complicated configuration. To study PD propagation in transformer windings, a simulation model is established in the frequency domain. Transfer functions of different propagation paths from PD location to measuring terminals are obtained by simulation. The simulation results demonstrate that transformer windings have different effect on the propagation of PD pulses in different frequency ranges, e.g. in the "oscillatory" frequency range PD signals are distorted, in the "capacitive" frequency range PD signals are attenuated only. The characteristics of transfer functions can be employed to locate PD sources: in the "oscillatory" frequency range, it can be located by analyzing the spectrum of measured PD signals; in the "capacitive" frequency range, it can be located by comparing the ratio of measured signals at two terminals with the prediction curve from simulation.