A liquid nitrogen switch and its working method

Abstract

The invention discloses a liquid nitrogen switch and a working method thereof. The liquid nitrogen switch utilizes liquid nitrogen as an arc-extinguishing medium and an insulating medium for the breaking current, the liquid nitrogen switch includes a dewar tank with a pressure-relieving nozzle, moving and static contacts immersed in the liquid nitrogen environment in the Dewar tank and a conductive rod, a moving end of the conductive rod extends beyond an end portion of the Dewar tank to connect with an operating mechanism, a static end of the conductive rod extends beyond the end portion of the Dewar tank to connect with a current transformer, outer circumference of the Dewar tank is provided with magnets, the Dewar tank is further provided with a nitrogen inlet, a liquid nitrogen inlet,a liquid nitrogen outlet, a temperature meter and a level gauge, a nitrogen storage tank is in communication with the nitrogen inlet, a pressurized air pump and a pressure gauge are arranged on the connected pipeline, a liquid nitrogen storage tank is connected with the liquid nitrogen inlet, a liquid nitrogen pump is arranged on the connected pipeline, the liquid nitrogen is widely used as the insulation medium and the cooling medium for superconducting devices and is widely applied to the superconducting devices, the liquid nitrogen switch can be used with the superconducting devices to share a refrigeration system with the superconducting system, and cooling cost is further reduced.

Description

technical field [0001] The invention relates to the technical field of current breaking of switching devices, in particular to a switching device using liquid nitrogen as an arc extinguishing medium and an insulating medium and a working method thereof. Background technique [0002] After long-term development of power switchgear, the insulating medium and arc-extinguishing medium in the interrupter chamber of the circuit breaker are constantly changing. At present, oil-rich circuit breakers and oil-less circuit breakers have gradually withdrawn from the market, replaced by vacuum and SF 6 Circuit breakers of various voltage levels as the arc extinguishing medium. However, due to the arc extinguishing characteristics, current interception and operating overvoltage are more likely to occur. Vacuum circuit breakers are limited to high-voltage applications. In high-current applications, the contacts are severely ablated, and the heat dissipation of the arc extinguishing chambe...

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Problems solved by technology

[0007] In view of the fact that the existing traditional power switchgear cannot well meet the requirements of the superconducting power transmission network, the invention provides a liquid nitrogen switch and its working method. The invention utilizes the good insulation performance and low temperature performance of liquid nitrogen as an insulation medium and The arc extinguishing medium interrupts the current

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