Testing of a 13.8 kV air-magnetic breaker in a steam environment

In order to obtain some insight into the performance of an air-magnetic circuit breaker in a steam environment, a 134.8 kV circuit breaker was required to interrupt a 9.3 MVA motor load while subjected to 110°C steam. The authors describe the technical concerns leading to the testing, how the testing was performed, and the observations recorded. Two tests were performed, at 88 s after steam release and some 7 min later, when steam condensation and breaker temperature were at their maximum (for the given steam profile). The breaker successfully interrupted the load twice and there was no flashover. The closing controls failed on the second reclosure attempt