A Microprocessor and Wavelets Based Relaying Approach for on Line Six-Phase Transmission Lines Protection

This paper introduces a microprocessor and wavelets based non communication relaying approach dedicated for on line six-phase power transmission lines fault detection, classification and faulted phase(s) selection. The approach uses wavelets for capturing the fault induced high frequency signals of currents and/or voltages. The captured high frequency signals are then used in conjunction with their energies to determine the faulted line and consequently for making a trip decision. For this purpose, a suitable wavelet for on line protection is chosen and tuned at a suitable band of frequencies. In order to investigate a real time performance of the introduced approach a microprocessor based laboratory prototype has been implemented and tested. The obtained results show that the approach is high speed in faulted phase(s) detection and insensitive for the fault inception angle, fault resistance, and line terminals.