A study of failure analysis in SF6 circuit breaker

The circuit breaker of SF₆ type has many advantages over conventional type, being better performance and dielectric properties. SF₆ circuit breaker are now being employed widely in substations for better electrical network functioning. Even then, it is associated with some failures which are reported in the field. Two kinds of circuit breaker are studied in this work with point of thermal behavior. A rated current is passed through SF₆ circuit breaker and thermal mapping is recorded at incoming terminal and outgoing terminal, enclosure and other points for investigations. The steady state condition of temperature is taken as reference in finding temperature rise over the environment condition. The temperature at predecided points of circuit breaker both for passed sample and failed sample are recorded. The data obtained is analyzed and attempt is made to understand the failure of SF₆ breaker in the context of excessive temperature than the prescribed limits of International Specifications. This paper deals with sample arrangement, experimental details, results and analysis. Both failed sample and passed sample have shown contrast performance in final analysis.