Fault-current limiter applications in medium- and high-voltage power distribution systems

Electronically triggered fault-current limiters have been used in medium- and high-voltage power distribution systems to limit the available short-circuit current to a lower level, so that the underrated switchgear can be operated safely. However, to insure a safe and proper usage of these devices, the following major operating parameters need to be considered: (1) selection of trigger level; (2) selection of di/dt; (3) effect of the capacitor bank and stray capacitances; and (4) coordination between these devices and phase overcurrent (o/c) relays at the faulted breaker. This paper will examine these major operating parameters, evaluate the performance of the current limiters under various simulated fault conditions, and develop application guidelines for current limiters.