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 1½-million-kva ``oil-poor'' porcelain-clad circuit breaker is shown, together with laboratory test results. A review is given of important field tests on a 138-kv single-pole unit, tested line to ground on a large 220-kv operating system up to approximately 2¼ million three-phase kva. Magnetic and cathode-ray oscillograms of these tests are shown.