A Faulty Section Identification Scheme in Thyristor Controlled Series Compensated Transmission Lines using Superimposed Currents

Thyristor controlled series compensator (TCSC) installed in transmission lines to increase power transfer capacity of the existing line presents challenges to distance protection relaying scheme. This paper addresses the issue of reverse over-reaching of distance relays in TCSC sectionalized transmission lines. Based on the observations, a new faulty section identification scheme has been proposed using superimposed currents to avoid reverse over-reaching of distance relays in TCSC sectionalized transmission lines. This can be achieved by extracting necessary features from the current signals and thereafter giving them to Support Vector Machine (SVM) and Random Forest (RF) classifiers. The feasibility of the proposed method has been tested on a 400 kV, 300 km long, TCSC sectionalized transmission line modelled using PSCAD/EMTDC. Upon testing 10,800 fault cases with diversified fault scenario, the performance of the proposed method has been found promising with an overall accuracy of 99.89%.