GB1081994A - Improvements relating to gas-blast electric circuit-breakers - Google Patents

Abstract

1,081,994. Gas blast switches. A. REYROLLE & CO. Ltd. May 13, 1964 [May 13, 1963], No. 18927/63. Heading H2B. In a multi-break gas-blast circuit breaker of the kind in which blast gas is discharged from a high pressure reservoir 20, across each break 61, 62 through a nozzle 34, 35 and into a cooling chamber 30 at lower pressure, the chamber or chambers 30 have metal or metallized surfaces 50 connected with the current path on one side of the break and co-operating with either a similar surface 50 of an adjacent chamber or with an electrode 52 connected to the other side of the break so as to form a voltage grading capacitor. The surfaces 50 may be the metal or metallized walls of the chambers 3U or separate plates secured thereto. Each adjacent pair of breaks is associated with one chamber 30 and comprise a bridging contact 63 on an insulating rod 64 movable rectilinearly by pneumatic means controlled by solenoid valves (Figs. 5, 7, 8, not shown) and co-operating with rigid fixed contacts 59, 60 within the high pressure reservoir 20. Each break has an arcing electrode (121) connected to a metal blast chamber 33 common to the two adjacent breaks and connected with the capacitor plates 50 of chamber 30; each blast chamber has a valve 32 exhausting through a pipe 31 into the chamber 30. Each chamber 30 comprises a pair of multi-walled polygonal toroidal tubes 41 having a plurality of staggered vents (Fig. 4, not shown) from which the cooled gases pass into the lower pressure tank 11 (Fig. 1, not shown) surrounding the breaker. The gas is recirculated by a pump (25). The contact structure is assembled on a frame 58 slidable from the tubular reservoir 20 on runners 55; connections to bushing conductors (16, 17) are made by sliding plug-andsocket connectors (66, 68). In a modification (not shown) the cooling chambers 30 are located within the high pressure reservoir allowing the surfaces 50 to be closer together to provide greater capacitance. Additional flat disc electrodes may be placed between the surfaces 50 and connected to the contacts 60 to improve the voltage grading. The spaces between the surfaces 50 may be filled with cast synthetic resin which may contain bubbles of a compressed inert gas of high dielectric strength. The surfaces 50 may alternatively be covered with a skin of P.V.C.