GB1287301A - Cubicle switchgear - Google Patents

Abstract

1287301 Switchgear structures DELLEALSTHOM 6 Oct 1969 [7 Oct 1968 30 Dec 1968 7 March 1969] 49063/69 Heading H1N In a cubicle switchgear circuit breaking and isolating means 101, 102 of each pole lie on a common axis the axes of the various poles lying parallel to one another and spaced apart in a plane perpendicular to a set of bus-bars 119, the circuit breaking and isolating means 101, 102 all being assembled as a withdrawable unit which can be coupled to a truck (Fig. 5, not shown) for removal and metal screens 107 being deployed automatically on withdrawal of the unit. In Figs. 1-10 (not shown) the circuit breakers are isolated by withdrawing them from the cubicle by means of the trolley and a screw and nut coupling. The screens are arranged to be drawn out from the back of the cubicle as the circuit breakers are withdrawn and to spread out as the unit leaves the cubicle. The three poles are arranged one behind the other in the cubicle with the bus-bars above and the cable inlets below the withdrawable unit; current transformers and an earthing/shorting switch are associated with the cable inlets. The earthing switch comprises a rod inserted from the front of the cubicle and therefore can only be operated when the circuit breaker unit and its handling truck are removed; its final movement may release the front cover of the compartment housing the cable inlets (Figs. 7, 8, not shown). A dummy unit may be inserted in place of the circuit breakers (Fig. 10, not shown); this places a screen between the bus-bars and cables. The front cover of the cable compartment moves to a position to prevent withdrawal of the dummy unit allowing servicing of the cables with the bus-bars live. As the circuit breaker unit is withdrawn a screen may be drawn across its top surface (Fig. 5, not shown) by a rack and pinion device coupled with the screw and nut. In Figs. 11-14 the circuit breakers 101 are isolated, by switch blades pivoted to each terminal, prior to withdrawal of the unit. Folding shutters 107 are coupled to the linkage operating the isolating switches. The shutters 107 can only be operated with the circuit unit in place when a pin 124 on the operating shaft 106 couples with the shutter mechanism. Shaped members 116, 117 prevent operations of shutters or isolators while the circuit breakers are open. To permit access to the cable compartments the slides in which the lower shutters 107 move may be pivoted upwards when earthing blades 108 have beenmoved to engage the cables. In a modification (Figs. 15-17, not shown) the bus-bars are at the bottom of the cubicle, the cables extending to the top and being connected to the isolating contacts by conductors embedded in a block of insulating material and by plug in current transformers.