High-Frequency Transients-Based Protection of Multiterminal Transmission Lines Using the SVM Technique

The protection of multiterminal transmission lines is a challenging task due to possible infeed or outfeed currents contributed from the taped lines. As a result, the first zone reach of a noncommunication-based scheme (e.g., impedance-based distance relays) usually cannot be extended more than a small portion beyond the tap point. This paper presents a protection technique based on the high-frequency transients generated by the fault to cover almost the total length of multiterminal transmission lines. For this purpose, appropriately designed line traps are installed at terminals of the protected transmission line, and the support vector machine is used to classify the internal and external faults based on the frequency spectrum of the current signals decomposed by the wavelet transform. Extensive simulation studies indicate that the proposed approach is well capable of discriminating between the internal and external faults and provides a very fast, secure, and reliable protection technique.