Parallel line integrated protection based on transient current polarity comparison

A parallel line integrated protection technique based on transient current polarity comparison is presented. An integrated protection relay interfaced to both CTs of the parallel lines, is responsible for the protection of the parallel lines. The polarity ofthe transient current component which comes from the faulted direction on the transmission line is different from the one which comes from the other emanating lines. Protection using this principle can protect not only all lines associated with a busbar, but also the emanating parallel lines. The paper outlines the potential problems, design and implementation of the parallel lines integrated protection based on transient polarity detection using wavelet transform. Simulation studies show that it is feasible to realize the parallel lines integrated protection utilizing the polarity of the transient current component.