Mitigation of Adverse Effects of Midpoint Shunt- FACTS Compensated Transmission Lines on Distance Protection Schemes

This paper presents practical solutions to mitigate the adverse effects on distance protection schemes when they are used to protect transmission networks that are compensated by shunt connected flexible AC transmission system (FACTS) controllers/devices. Two types of shunt-FACTS devices, static var compensator (SVC) and static synchronous compensator (STATCOM), are considered and designed to regulate the midpoint voltage of the transmission line. The mitigation techniques are implemented in commercial relays and tested using real time digital simulator (RTDS). The results show the effectiveness of the proposed modifications to the channel aided distance protection schemes under various faults and varying operating conditions.