Modelling of Distance Relays and Impact of TCSC on the Protection of Long Distance Transmission Lines

Abstract

Power system protection is one of the most important and exciting topics, which has been attracting the attention of both academic institutions and utilities ever since the power systems came into being. For the proper operation of the power system, an effective, efficient and reliable protection scheme is desirable. The power system components, which include synchronous machines, bus bars, transformers, transmission lines, distribution systems consisting of complex as well as composite loads are designed to operate under normal conditions of voltage, frequency and power factor. However, due to any reason say some fault; if any of these quantities become abnormal it is necessary that there should be a device which senses these abnormal conditions. This is necessary because the power system components can never be designed to withstand the worst possible conditions, as it will make the whole system highly uneconomical.Therefore, if such abnormal operation takes place in any element or component of the power system network, it is desirable that the affected components are removed from the rest of the system reliably and quickly so as to restore power to the remaining system under normal conditions as soon as possible. In this paper, the effect of TCSC on the protective zone is presented. This paper also presents the modeling and performance analysis of a distance relay in Matrix Laboratory (MATLAB).

Keywords: distance protection, FACTS, impedance trajectory, MATLAB/Simulink, Mho relay, TCSC