OPTICAL-FIBER INVESTIGATION OF THE ARC DYNAMICS OF A SPIRAL ARE CURRENT LIMITING INTERRUPTER

An optical fibre system with 48 optical fibre probes, a 48-line digita l input/output card and software to import 48 bits of data at a data a cquisition rate of 42 x 10(3) samples/s has been developed and used to investigate the arc dynamics of a spiral arc current-limiting interru pter. Arc position, are velocity and the current interrupting characte ristics for two separate electrode configurations, ring-ring and rod-r ing, were analysed using experimental results. A cylindrical test cham ber with 115 mm height between the electrodes and 270 mm circumference gave an average are root velocity of over 100 m/s and an are root rot ation of about ten times per cycle. The effect of electrode polarity, slot size and overall design parameters on the performance of the spir al are current-limiting interrupter were considered.