An Innovative Test Method for Multi-Chamber High Voltage Circuit Breakers

Abstract

High voltage circuit breakers are often designed using multiple interrupting chambers connected in series for each pole/phase. These breakers need to undergo type tests and development tests. Especially for very high voltages, no test facilities may exist to perform a short circuit test on a complete breaker. Therefore, the possibility exists for testing only a part of the circuit breaker, termed as “unit testing”. For unit testing, different approaches can be adopted which include only a part of the circuit breaker. Especially for metal enclosed switchgear like Gas Insulated Switchgear (GIS) or a Dead Tank Breaker (DTB), unit testing has required a lot of additional effort and sometimes even a design change of the circuit breaker. In view of the above, a new innovative test method is proposed which uses a Metal Oxide Varistor (MOV) to bridge one unit/interrupting chamber of the test device. This method not only provides ease of testing but also gives sufficient feasibility for proof of dielectric withstand capability in relation to short circuit interruption. The presented method reduces the effort for necessary design changes to a minimum compared to other methods used. The proposed method has been validated by means of simulation and testing.