Impact of Shunt-FACTS on Distance Protection of Transmission Lines

This paper presents the performance of distance protection of transmission lines when compensated with shunt flexible AC transmission system (FACTS) controllers/devices. The performance of distance protection is evaluated for shunt-FACTS controllers applied for mid-point voltage control. The impact of two types of shunt FACTS controllers, static VAr compensators (SVC) and static synchronous compensators (STATCOM) on the transmission line distance protection are studied for different fault types, fault locations and system conditions. The dynamics of the shunt-FACTS controllers with their associated control systems are considered and simulated using RSCAD/RTDS testing environment. The performance of both the basic/non-pilot distance scheme and a directional comparison blocking (DCB) scheme are evaluated in this paper. The results of the commercial relay testing show the adverse effects of mid-point shunt-FACTS compensation of transmission line on both non-pilot and DCB distance protection schemes