Electromagnetic Time Reversal to Locate Partial Discharges in Power Networks with Inhomogeneous cables using the Transmission Line Matrix Method

This paper describes a method for the on-line location of partial discharges (PD) in power networks based on the electromagnetic time reversal (EMTR) theory. PDs are localized electrical discharges that partially bridge the insulation between conductors and that start in cable insulation defects. Since the insulation degradation is often caused by PD, PD is regarded as a symptom of insulation degradation and on-line PD location is considered the most suitable monitoring method of network integrity assessment to prevent faults and improve network resilience. The proposed method, reversing in time the measured PD signals, refocuses them to their source allowing the location of PD site. The method uses the Transmission Line Matrix modelling approach to solve the backward propagation equations. In this paper, the effectiveness of the EMTR-based method to locate PDs in inhomogeneous power lines, using only one measurement point at a line end, is investigated and proved in simulation.