Hybrid current limiting interrupting device for 3-phase 400 V AC applications

Hybrid current-limiting and interrupting device (HCLID) for 3-phase 400 V AC applications was worked out by the authors and subjected to switching operation tests. The design of the 3-pole HCLID model was based on a single pole HCLID model of breaking capacity 75 kA (RMS), previously reported by the authors elsewhere. The research showed that the main parameters for characterising the 3-pole HCLID's breaking operation as the fault clearance time, the peak let-through current and also Joule's integral of the let-through current under severe fault conditions, are very advantageous in comparison to the breaking performance of conventional mechanical circuit breaker. The following experiments were successfully carried out on a physical model of 3-pole HCLID: short circuit current limitation and interruption in 3-phase low voltage systems, in the case of 3-phase and 2-phase faults; protection of diode rectifier against internal and external (DC output side) faults. The 3-pole HCLID can perform the function of a universal "life" overcurrent protection against disastrous fault effects, for 3-phase 400 V AC various applications.