GB751877A - Improvements relating to high-voltage electric switchgear - Google Patents

Abstract

751,877. Switchgear structures. REYROLLE & CO., Ltd., A. Feb. 23, 1955 [Feb. 24, 1954] No. 5458/54. Class 38(5) In a high-voltage, three phase duplicate - busbar switchgear housed in a building and employing live tank feeder circuit-breakers 4, air insulated busbars 6, 7 and double-break busbar isolators 8, 9, each alternative set of busbars has three phases, A, B and C, housed in three separate compartments and corresponding phases of the two sets housed in adjacent compartments 1, 2. Each pair of adjacent compartments 1, 2. may have a common partition 3 provided with windows so that one of the compartments may be used, when its busbar is dead, as an inspection chamber for the adjacent live busbar. Each circuitbreaker 4 is housed in a separate compartment 5. Isolators 8, 9 are provided for each pair of busbars 6, 7 and the bridging conducter of each isolator is carried in a pivoted insulating bushing 11 extending through the ceiling 12 of compartment 5. Fixed alternative main and reserve busbar isolator terminals 13, 14 are carried by insulating posts so that they can be engaged by the bridging conductor of the associated isolator 8 or 9 and thus connected to the associated busbar 6 or 7. Each busbar isolator is also movable to an open position in which the bridging conductor is earthed. Each compartment 5 houses a line terminal 15. A line isolator 17 is permanently connected to the lower terminal 19 of the circuit-breaker and the terminal 13 is permanently connected to the upper terminal 20 of the circuit-breaker. In the open position the isolator arm 18 engages terminal 13. The terminal 14 is connected to a by-pass isolator 22 having an arm 23 which connects terminal 14 to either of terminals 13 or 15, in the latter position by-passing the circuitbreaker 4. A metal screen 24 can be moved to divide compartment 5 into two enclosures, enabling the circuit-breaker to be examined when it is by-passed. A voltage transformer 25c is housed in compartment 5c. In alternative arrangements the by-pass and line isolators may be replaced by permanent connections, no screen 24 then being provided, or each phase of the circuitbreaker may be of the air-blast type provided with a sequentially operated seriesbreak isolator which also serves as the line isolator.