Optical fibre investigation of the arc dynamics of a spiral arc current limiting interrupter

An optical fibre system with 48 optical fibre probes, a 48-line digital input/output card and software to import 48 bits of data at a data acquisition rate of 42×10³ samples/s has been developed and used to investigate the arc dynamics of a spiral arc current-limiting interrupter. Arc position, arc velocity and the current interrupting characteristics for two separate electrode configurations, ring-ring and rod-ring, were analysed using experimental results. A cylindrical test chamber with 115 mm height between the electrodes and 270 mm circumference gave an average arc root velocity of over 100 m/s and an arc root rotation of about ten times per cycle. The effect of electrode polarity, slot size and overall design parameters on the performance of the spiral arc current-limiting interrupter were considered