Research on localization of partial discharges in transformers based on wideband equivalent circuit

Abstract

When partial discharge occurs within transformers， the pulse current signal propagates along the winding. Detecting this pulse current signal at both ends of the winding enables the identification of partial discharge within the transformer. To this end， a wideband equivalent circuit model for the transformer is established. In high-voltage windings where partial discharges are likely to occur， partial discharge pulses are applied between different wound disks and the ground to simulate the discharge to the ground at different locations of the high-voltage winding. Pulse current signals are then collected at the end screen of the high-voltage casing and at the neutral point to study the propagation rules of the partial discharge pulse current signal at different locations within the transformer windings. Through calculations， it is observed that the energy ratios of pulse current signals in two distinct frequency bands are linearly correlated with the distance ratio of pulse current propagation， and the maximum error observed in this context is 9.80 wound disks. This method facilitates localization of partial discharge within the transformer， and the results of field experiment subsequently validate the effectiveness of this localization technique.

Keywords

• transformer
• winding
• partial discharge localization
• pulse current method