| In recent years,with the rapid development of the national economy,the number of transmission lines has increased year by year,providing a guarantee for the transmission of clean power.However,the traditional "blocking" lightning protection measures are not effective,and the lightning protection of transmission lines has not been fundamentally addressed.Based on the theory of parallel gap,a new type of arc extinguishing device is proposed in this paper.The device can effectively cut off the power frequency continuous flow of lightning protection gap and prevent arc reignition by injecting high-speed and high-pressure air.In this paper,the electric potential gradient,temperature,volt-ampere characteristic,diameter and plasma current of arc are studied at first.Secondly,the ARC model is established by establishing the equation to describe the arc plasma and analyzing the interaction between the high-speed and high-pressure air flow of detonation stage and ARC plasma with the ARC magnetic fluid model,the interaction between high-speed and high-pressure gas flow and ARC plasma is analyzed.The complex coupling process between high-speed and high-pressure air flow and arc is simulated by using COMSOL simulation software,and the temperature cloud chart of reaction environment at different time in the development process is finally obtained,the temperature drops slowly away from the nozzle,but the final temperature drops below3000K.Finally,in order to test whether the shock intensity of the device conforms to the national standard,the lightning impulse discharge test is carried out,and the power frequency current ARC extinguishing test is carried out to test the effectiveness of the device,it is verified that the ARC can reduce the temperature rapidly under the action of high-speed and high-pressure flow,and finally extinguish at 4.2 ms.Based on the insulation coordination test of the pulsed gas arc extinguishing device at 500 k V voltage level,it is concluded that the insulation coordination ratio of the pulsed gas arc extinguishing device and the insulator is 1:0.9,which can ensure the ARC flashover along the pre-set arc extinguishing channel,and the pulsed gas current arc extinguishing device can work normally.From the actual operation,the device can reduce the lightning trip-out times of transmission lines,which can promote the safe and stable operation of transmission lines and is worth popularizing. |
