Steady State Current Limiting Characteristics of Fault Current Limiter at Three-Phase Short Circuit Fault in Electric Power System

Fault current limiter (FCL) is a power apparatus which suppresses the fault current by generating the limiting impedance when the fault occurs and expected to be applied to electric power system. In the design of the FCL, it is important to choice the limiting impedance properly according to the purpose of the introduction of FCL, the installed location of the FCL in the power system and so on. In this paper, we investigated the influence of the magnitude and phase angle of the limiting impedance on the current limiting performance in the steady state after the FCL started the limiting operation based on the circuit theory. We supposed two installed locations of the FCL, i.e., the bus exit and bus tie. In the case of the introduction of the FCL on the bus exit, the limiting impedance having same phase angle as that of system impedance can bring about the highest limiting effect for same magnitude of limiting impedance. On the other hand, in the case that the FCL is installed on the bus tie and relatively high limiting performance is desirable, there is the situation where the limiting effect grows with phase difference between limiting impedance and power system.