Influence of fault current limiter on allowable interconnecting time period of customer power system with synchronous generator

Distributed generators will be disconnected from a grid with a short-circuit fault to protect the generator and load in the customer system. In order to keep an isolated operation of the generator after the disconnection of customer system from the utility system, the customer system must adjust the power balance between supply and demand. This paper has investigated an influence of a fault current limiter on a probability of isolated operation after the disconnection of customer system with a synchronous generator from a medium voltage feeder. An allowable interconnecting time period, which is a critical time period from the fault occurrence to the isolated operation, has been simulated. It was assumed that the fault current limiter was installed in an interconnecting line between customer system with the synchronous generator and power distribution system. It was found that a resistive type fault current limiter does not improve the allowable interconnecting time period since the consumption power of fault current limiter causes the generator to decelerate. However, it was shown that the allowable interconnecting time period increases owing to the application of inductive type fault current limiter. This is because the active power of load is nearly equal to the generator output.