An effect of fault current limiter to non-utility generator shaft torque under voltage sag

Voltage sag can affect the customer's voltage sensitive loads. To minimize the influence of the voltage sag, the bus-tie breakers are used to disconnect the critical loads and the in-house generator from the utility power systems by detecting the voltage magnitude when the power system fault occurs. Hence, the voltage sag duration at the bus to which the critical loads and the in-house generators connect, is varied according to the types of the breakers and the voltage detection circuit. Two types of switch-gears are demonstrated: a conventional circuit breaker and a high-speed fault current limiter.