Protection Issues Associated with the Proliferation of Static Synchronous Compensator (STATCOM) Type Facts Devices in Power Systems

With the increase in the number of static synchronous compensator (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 mal- operate under system fault conditions, as this will result in the loss of stability or the security of the system, which defeats the main objective of installing a STATCOM. As STATCOM type FACTS devices have fast response and their functional characteristics and control system introduce dynamic changes during fault conditions in a transmission line it is important that distance relays perform correctly irrespective of such dynamic changes introduced during fault. In this paper, a general survey of the FACTS devices employed in the power systems is presented. This is 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.