Fault detection and faulty phase(s) identification in TCSC compensated transmission lines

Abstract

Detection of fault in compensated transmission lines during power swing is a complicated task. The distance relay functioning is blocked during stable power swing while it is expected to react as quickly as possible to faults. Non-linear behaviour of metal–oxide varistor and thyristor-controlled series capacitor (TCSC) make even the issue more complicated. In this study, the cumulative sum of the phase current second harmonic is proposed as a unique fault isolation feature. Various low-impedance, high-impedance, symmetric, and asymmetric types of fault signals are collected and to exhibit the algorithm robustness, several disturbance events and measurement noise are applied. The algorithm is conducted over a single machine infinite bus, and a Western System Coordinating Council 9-bus, 3-machine network with TCSC compensated lines. The results of extensive simulations indicate that the algorithm performs excellent regarding some recently developed algorithms. Accurate single, two of three faulty phases are marked despite disturbances and powerful swing. As so, a simple and effective fault detection algorithm has been introduced, which correctly resolves the challenges.