Application of electromagnetic time reversal for online locating partial discharges in power networks

Partial discharges (PDs) from inhomogeneities, potential sites for future faults, in cable defects, generate high-frequency pulses traveling along electric power networks. Online PD signal detection and location permits proactive maintenance, minimizing the impact of or, ideally, preventing outages, reducing the overall repair time and the customer minutes lost. PD monitoring techniques are commercially available, but their cost-effective implementation requires guarding large parts of a network at once. The signals experience multiple reflections from within the monitored sections and from the externally connected sections. These techniques require that the incident waveform's structure be identified with respect to reflection points in order to locate the PD origin. This challenge can be relaxed by performing synchronized measurements in more than one observation point along the network or by involving complex denoising techniques. This chapter presents a method for localizing the source of PD using the Electromagnetic Time Reversal (EMTR) theory and shows its potential to improve PD location performance in complex network configurations. EMTR has the advantage of requiring no a priori knowledge of the waveform structure. Furthermore, the method makes it possible to localize a source using measurements in one observation point.