Three-position isolating switch

Abstract

The invention discloses a three-position isolating switch for overcoming the problems that electric field strength between alternative and opposite isolating fractures of the existing three-position isolating switch is higher, the insulating strength requirement can be satisfied by only charging high-pressure sulfur hexafluoride gas, and a gear rack which is adopted for meshing drive has big noises, and bad security and reliability; a middle fixed contact adopts a hyperbola body, a telescopic field control spherical conductive cover assembly is mounted in a hole in an isolating fixed contact,wherein the hole is connected with a movable contact and is in an insolating fixed contact, and a brass nut is matched with an insulating screw to form the screw drive; compared with the prior art, the three-position isolating switch has the beneficial effects that the electric field distribution is improved to reduce the electric field strength between alternative and opposite isolating fractures and to improve the insulating performance; the three-position isolating switch is suitable for low-pressure environments so as to reduce the use of the sulfur hexafluoride gas and to improve the security of the product; and since the movable contact can move stably and is free from noise in the motion process, the service life of the machinery product is improved, and the operation of the deviceis more reliable.

Description

technical field [0001] The invention belongs to the technical field of high-voltage electrical appliances, and in particular relates to a three-position isolating switch used in an inflatable cabinet for charging 0.1-0.2 Mpa low-pressure sulfur hexafluoride gas at a voltage level of 126kV. Background technique [0002] In the prior art, the three-position isolating switch used in the sulfur hexafluoride inflatable cabinet of the 126kV high-voltage system is limited by its structural form and structural size, especially the middle static contact adopts a small-diameter cylinder, and the two ends The fillet radius is small, generally 8-10mm, and the electric field strength between phases, opposite grounds and isolated fractures is high, so it needs to be filled with sulfur hexafluoride gas at high pressure (generally the inflation pressure is 0.5-0.6MPa). To meet the requirements of its insulation strength, since sulfur hexafluoride gas is one of the greenhouse effect gases re...

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Problems solved by technology

[0002] In the prior art, the three-position isolating switch used in the sulfur hexafluoride inflatable cabinet of the 126kV high-voltage system is limited by its structural form and structural size, especially the middle static contact adopts a small-diameter cylinder, and the two ends The fillet radius is small, generally 8-10mm, and the electric field strength between phases, opposite grounds and isolated fractures is high, so it needs to be filled with sulfur hexafluoride gas at high pressure (generally the inflation pressure is 0.5-0.6MPa). To meet the requirements of its insulation strength, since sulfur hexafluoride gas is one of the greenhouse effect gases restricted by the "Kyoto Protocol", filling high-pressure sulfur hexafluoride gas means that the amount of sulfur hexafluoride gas used Larger, not conducive to environmental protection, therefore, reducing the use and emission of sulfur hexafluoride gas is a means and measure to protect the environment

In addition, in the prior art, the drive of the moving contact of the three-position isolating switch adopts the meshing transmission of the rack and pinion, which is noisy, and it is easy to grind metal chips from the tooth surface during the meshing transmission process, resulting in fracture insulation damage. Cause major accidents and reduce the safety and reliability of power supply

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