A Conventional Distance Protection for Series-Compensated Lines Considering TCSC Protected by a Metal Oxide Varistor

In this paper, a modified distance protection setting method is proposed to use the conventional distance relays for the transmission lines. The comprehensive studies regarding the impact of the thyristor-controlled series capacitor (TCSC) on a conventional distance relay are shown that the TCSC affects the operation of distance relays not only at the series compensated lines but also at the adjacent lines. The proposed method uses the equivalent impedance of the TCSC considering a metal oxide varistor (MOV), which is one of the overvoltage protection element for the TCSC to calculate the setting values which can prevent the mal-operation of the distance relays. To analyze and evaluate the performance of proposed method, a series of simulation studies were carried out with the PSS/E and PSCAD/EMTDC environment.