Partial discharges in power transformers

Abstract

Tansformers are among the most responsible and expensive elements of the power system, therefore monitoring the technical condition of the transformer is an important and urgent task. One of the signs of aging of insulation in a transformer may be partial discharges (PD), leading to its further failure. The use of monitoring systems based on PD analysis makes it possible to prevent the severe consequences of short circuits in transformers and, as a result, achieve significant economic effects during the operation of controlled high-voltage equipment. The transformer monitoring system based on the partial discharge method is complex and not always effective, because fixed discharges in transformer insulation can be observed for years and do not lead to breakdown, and among the PD it is not always possible to identify the leader's transition to the through phase in time, which creates sufficient conditions for breakdown. In practice, the discharge test is performed using chromatographic analysis of dissolved gases in oil (CADG) or by measuring discharge activity. The article analyzes the effectiveness of PD control methods and the need to develop mathematical models of partial discharges that allow studying the dynamics of the streamer-leader transition in controlled isolation.