Modeling and simulation of the impacts of STATCOM control schemes on distance elements

The performance of a distance protection scheme along with related supervisory elements is investigated when a shunt connected static synchronous compensator (STATCOM) is tapped to the midpoint of a transmission line. The paper examines responses for different fault types and locations while the STATCOM absorbs reactive power and is being controlled by two different control schemes. An emtp-type model has been developed to simulate the power system and the impact of the control modes of the STATCOM device. Also, a memory polarized distance relay, digital filter, supervisory element, and trip logic are modeled. Different simulation scenarios are tested and evaluated. Distance relays tend to overreach when STATCOMs are injecting inductive current. However, the simulation results also show that distance relay performance is affected by the control scheme of the STATCOM.