Investigation on the phase selection criterion based on improved modular fault component

Under the conditions of the various system parameters and fault types, the performance of the phase selector based on modular fault component are analyzed. Compared with the phase selector based on difference of two phase currents, this phase selector is better in terms of overall performance. However, this phase selector cannot achieve theoretical selectivity for a real fault. Furthermore, this phase selector may lack of sensitivity where the relay is equipped on the side of weak source. So an improved scheme is presented to make up for above shortcomings, and the EMTP simulation has shown that the improved scheme is effective.