Puffer type liquefied-gas self-injection circuit breaker

Abstract

A puffer type liquefied-gas self-injection circuit breaker, used for the interruption at low temperature of a high current carried by a high-voltage power line. The circuit breaker comprises a first fixed contact and a compression chamber. The compression chamber has a bottom part which is fixed and an upper part of which is movable in the axial direction with respect to the bottom part. The upper part of the compression chamber comprises a second contact and an envelope concentrically disposed thereabout. An insulating nozzle is formed in a top portion of the envelope. The internal wall of the envelope is so shaped as to exactly match the external profile of the bottom part of the compression chamber. The breaker is also equipped with a liquefied-gas self-injection system which injects the liquefied-gas from their storage tank via a feed line and valve directly onto the electric arc formed at the moment of current interruption. This system comprises an injection chamber located in the wall of the moving part of the compression chamber. The injection chamber is terminated at one end by a narrow injection channel acting as a nozzle directed towards the electric arc while the other end rests on a compression piston formed by a pre-injection chamber. The latter forms an integral part of the fixed bottom part of the compression chamber and is equipped at its top end with a check valve permitting its use as a compression piston when the valve is closed and permitting the transfer of liqufied-gas to the injection chamber when the valve is in the open position. A storage tank placed at the bottom of the compression chamber provides for the recuperation by gravity of all the liquefied-gas in the apparatus.