Electromagnetic Time Reversal for Power System Reliability

This paper introduces the results obtained so far using electromagnetic time reversal (EMTR) to locate partial discharges (PDs) in power systems, aiming to improve their reliability. PD events, occurring inside insulator defects, can lead to faults or supply interruptions. Accurate PD localisation methods are crucial tools for protecting power systems and improving their resilience. In EMTR-based PD localisation [1], the measured PD signals are time-reversed and re-emitted back into the system model. During the simulation of the time-reversed signals, the maximum value of the signal is expected to occur at the source location. Results so far indicate that the EMTR method, using only one observation point (OP), exhibits significantly improved performance compared to classical approaches based on Time Domain Reflectometry. It has been demonstrated that EMTR is: 1. Robust in the presence of noise, 2. Effective in systems with multiple inhomogeneities, and 3. Capable of handling heavy distortion of the PD signal caused by interfering signals from the cable circuit. As evidence, Fig.1.a) shows the localisation results for a 2 km cable under noisy conditions [1], and Fig. 1.b) presents the results when the PD signal is distorted by interfering signals at the OP, in the Ring Main Unit (RMU), originating from the PILC circuit sections [2]. In the investigated straight system configurations, the method achieves PD localisation with a relative error of less than 1% of the total line length, using only one OP.