Single-Phase-to-Earth Faulty Feeder Detection in Power Distribution Network Based on Amplitude Ratio of Zero-Mode Transients

Abstract

The single-phase-to-earth fault (SPTEF) current is weak in neutral ineffectively grounded systems. High fault impedance, noise and arc impair the fault feature, which increases the difficulty of faulty feeder detection. Based on the propagation characteristics of zero-mode transients (ZTs), this paper proposes a faulty feeder detection criterion by utilizing the amplitude information of the ZTs captured at both terminals. To conduct the criterion, the historical data of the ZTs recorded at both terminals of each feeder with a bus fault is collected. The standard amplitude ratios of the frequency components in the ZTs of each feeder are extracted by S-transform. After a SPTEF is detected in the system, the actual amplitude ratios of the ZTs are calculated and compared with the standard ones. Theoretical analysis and simulation indicate that the maximum ratio between the standard and actual ratios corresponds to the faulty feeder. In implementation of the criterion, both high sampling frequency and accurate synchronization are not required. A 10kV single-end radial distribution network is constructed by PSCAD/EMTDC. Various fault simulations are carried out and the calculation results demonstrate that the proposed criterion has high reliability and is not affected by neutral grounding mode, fault initial condition, high impedance fault (HIF) and noise.