Novel algorithm based on fault type to extract fault components

This paper presents a novel method which is capable of extracting fault components at arbitrary time after fault occurrence. From the result of phase selection, this approach firstly calculates the zero sequence and negative sequence fault components at the location where the protection relay is installed. Then it calculates the positive sequence fault components in accordance with the fault boundary condition. Finally, phase fault components are obtained by synthesizing sequence fault components based on the symmetrical components theory. Comparing with the currently available methods that can only obtain the original short-time fault components, this novel algorithm can extract fault components at arbitrary time after fault occurrence. Hence it may be employed for the fault components in back-up protections to improve their performance.