Transient Polarity Comparison for Integrated Protection of Distribution Network

This paper presents a novel integrated protection scheme for distribution networks using the transient polarity directional comparison technique. The technique is based on the detection and processing of fault generated transient current signals, in which specially designed protection relays are installed at each substation of a distribution network. The transient detection unit of the relay detects the faulted generated transient current signals. The transient polarity identification algorithm is then applied to the signals to identify the polarity of the signal detected. The direction of a fault is determined by comparison of the polarity of the signals derived from all the line sections connected to the substation. The actual faulted section is identified by processing the directional information from various substations. Simulation results presented in the paper demonstrate the feasibility of the scheme.