Modeling of operation of loss of excitation relay in presence of shunt FACTS devices

The proposed modeling of LOE relay operation is negative offset mho distance relay with two zones. The operation of loss of excitation relay will be delayed because of the existence of shunt FACTS devices along with the power system network proposed in this paper. This delay avoids mal-operation of the relay especially from power swings and allows field recovering synchronous generators to regain their capability. Due to presence of shunt FACTS devices, there are chances of mal-operation of LOE relay and it is expected that loss of excitation relay should not operate under any abnormality except excitation failure. This poses a challenging task for power system protection. The coordination between shunt FACTS devices and loss of excitation relay is discussed and modeled for proper discrimination in paper along with results of simulation strategy.