Photoconductive switches for AC circuit protection

The basic suitability of the photoconductive circuit element (PCE) for protective switching applications in AC power transmission and distribution circuits is examined. Specific applications include circuit breakers and fault-current limiters. This work considers a hybrid switching mechanism, which consists of a parallel arrangement of the PCE with a low-capacity mechanical switch. Electrical, optical, and thermal models are developed for the PCE device, which are incorporated in a system-level computer simulation of a power test circuit. Simulation results show the feasibility of the hybrid switching concept, although device sizes appear to be relatively large due to thermal dissipation requirements.<
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