A fast faulty phase selection algorithm based on S-transform

This paper proposes a novel approach to faulty phase selection using S-transform and phase current integration for the fast transmission line protection. The paper analyzes the modulus characteristics of various types of fault and the characteristics of phase current for two phases to ground fault. On the basis of it, the phase selection algorithm first uses S-transform to get single frequency phasor of module components at a specific time, and then the relation among module phasors is analyzed to classify the fault type. The algorithm use phase current integration distinguishes the faulty phases in the two phases to ground circumstance. The PSCAD simulation results show that the algorithm can quickly and accurately identify the fault phases, and the identification performance is not affected by the fault position, fault inception angle, fault resistance and the structure of bus.