Impact of STATCOM on distance relay - Modeling and simulation using PSCAD/EMTDC

With the increase in the number of STATCOM type FACTS devices in transmission lines, operation of distance relays in transmission lines are affected. It is very important that the distance relays do not maloperate under system fault conditions, as this will result in the loss of stability or the security of system, which defeats the main objective of installing a STATCOM. A STATCOM or Static synchronous Compensator is a regulating device used on alternating current electricity transmission networks. An apparent impedance calculation procedure for transmission line incorporating STATCOM based on the power frequency sequence circuits has been explored. The simulation results show the impact of statcom on the Distance protection relay during different fault conditions; the influence of location of STATCOM, the setting of STATCOM control parameters and the operation mode of STATCOM are studied as well. The results are presented in relation to a 138 kv transmission system employing STATCOM. Followed by a review of the effects of a STATCOM connected at the midpoint of a transmission line on the performance of distance protection relays using PSCAD software.