The vertical-flow interrupter and its application to “oil-poor” circuit breakers

The historical background of the development of the vertical-flow interrupter for “oil-poor” circuit breakers is reviewed. A description of the interrupter and its theory of operation is given. The application of two of these interrupters to a 138-kv 1 1/2-nillion-kva “oil-poor” porcelain-clad circuit breaker is shown, together with laboratory test results.