High-Frequency-Based Transmission Line Percentage Differential Protection With Traveling Wave Alignment

This paper presents a wavelet-based differential protection algorithm for transmission lines. It uses restraint and operating components obtained with high-frequency components of a few kHz from instantaneous energy values of the real-time boundary stationary wavelet transform instead of low-frequency components from phasor estimation. It does not require capacitive current suppression as well. Therefore, the proposed method overcomes the limitations of conventional percentage differential protection. Furthermore, the proposed technique uses traveling wave theory to perform the current sample alignment at a few kHz, thereby, not requiring the global positioning system (GPS). The performance of the proposed method is evaluated through extensive simulation of 21,450 realistic cases contemplating internal faults, external faults, high-impedance faults, faults with outfeed, line energization, and CT saturation. When compared to a conventional percentage differential protection the proposed protection method is able to detect faults up to 5 times faster, presenting a success rate of 100% against 98,2% achieved by the conventional one.