Wavelet-based relay agent for isolating faulty sections in distribution grids with distributed generators

This paper presents an agent based protection scheme to detect and isolate the faults in a distribution system with high penetration of distributed generation. An algorithm that uses wavelet coefficients of the transient fault currents is proposed for the identification of faulted sections. The algorithm is a hybrid of two techniques: one that determines the direction of fault currents based on the sign of wavelet coefficients and the other that estimates the distance to a fault based on the time interval between the travelling waves (and their reflections) arriving from the fault. Studies with a simulated distribution system indicate that the proposed method can correctly recognize the faulty sections.