An algorithm for partial discharge location in distribution power transformers

Partial discharges (PDs) are a major source of insulation failure in power transformers. Techniques for locating a PD source are of major importance in both the maintenance and repair of a transformer. A technique is described for locating a PD in a distribution power transformer. To study the propagation characteristics of a PD, a simulation model was developed for the transformer winding and the PD pulse. The terminal signals caused by PDs at different locations were analysed and the features related to the location extracted. An algorithm using feature template matching was developed for locating the PD source. Experimental tests carried out on a 110 kV continuous disc-type winding have verified the validity of the location algorithm. Results indicate that a location accuracy better than 5% of the winding length is normally achieved.