SVM based zonal setting of Mho relay for transmission line having TCSC

Presence of series FACTS (Flexible Alternating Current Transmission System) device significantly affects the performance of protection system and may create security and reliability issues. This paper introduces a novel approach for zone identification in transmission line employing Thyristor Controlled Series Capacitor (TCSC). The technique depends on the modified apparent impedance seen by the impedance relay for all possible operating conditions. In this technique the Support Vector Machine (SVM) is used for discriminating faulty zone (zone 1 or zone 2). In addition an optimization technique viz. Genetic Algorithm (GA) is used to optimize SVM parameters. A typical 220 kV system was simulated in PSCAD/ EMTP software and the results show that the proposed scheme is secure, accurate and reliable under the wide variation in power system parameters like load angle, fault resistance, fault location, inception angle and compensation level.