A Novel Partial Discharge Localization Method in Transformer based on Signal Propagation in Winding

Partial discharge is one of the important causes of transformer faults. The detection and localization of partial discharges in transformers are of great significance to ensure the safe operation of power systems. The finite element model of the transformer winding was built, lumped parameters of the transformer winding were solved by the finite element method. The equivalent circuit with two disks as the unit of transformer winding was established, and the propagation principle of the pulse signals excited by main insulation partial discharge and longitudinal insulation partial discharge were studied. Research showed that the signals of the main insulation partial discharge received at both ends of the winding were of the same polarity, and the pulse amplitude attenuated with the increase of the propagation distance. The localization of the main insulation partial discharge could be realized by calculating the proportion of energy in the middle-frequency region; The longitudinal insulation partial discharge signals received at both ends of the winding were of different polarity, and the pulse amplitude hardly attenuated with the increase of the propagation distance. the Localization of the longitudinal insulation partial discharge could be realized by calculating the arrival time of the first peak of the pulse. This study provided a new method of electrical localization of the partial discharge in transformer