Investigation of Interrupting Performance of Puffer Type Gas Blast Circuit Breaker Under Various Nozzle Clogging Conditions

The interrupting ability of a puffer type Gas Blast Circuit Breaker (GCB) was investigated under various nozzle clogging conditions. A model puffer type GCB was used in the interrupting experiments, in which nozzle diameter, nozzle geometry and current wave form were varied. The following results were obtained from the experiments, 1 At a nozzle current density of 2.5-5.5kA/cm2, the low puffer pressure makes it possible to interrupt a current with a large dI/dt. 2 An increase of base gas pressure effectively contributes to improving interrupting ability. 3 The puffer chamber pressure rise which is caused by excess nozzle clogging does not improve interrupting ability.