High-Speed Protection Scheme Based on Initial Current Traveling Wave for Transmission Lines Employing Mathematical Morphology

In this paper, a novel high-speed protection scheme, for transmission lines based on initial current traveling waves and employing mathematical morphology (MM) is proposed. This scheme, by comparing polarity and arrival time of initial current traveling wave from two terminals of the protected line, can discriminate the fault direction and internal faults from external faults rapidly. A new MM filter to extract transient components from fault-induced transient signals is designed. This MM filter can fast and accurately detect the arrival time and polarity of traveling waves in all conditions. Extensive simulation studies using EMTP and MATLAB have been carried out to evaluate the validity and reliability of the proposed scheme. The simulation results show that the proposed protection scheme can fast and reliably discriminate the fault direction and the internal faults from external faults in the most of conditions, especially in high impedance fault and low inception angle fault situation. The protection performance is immune to fault resistances, fault inception angles, fault types and fault location.