Influence Mechanism of Dielectric Coated Electrodes on Metallic Particle Lift-Off in SF6 Gas under DC Voltage
Lü Fangcheng1, Liu Hongyu1, Li Zhibing2, Dong Meng1, Yan Xianglian2
1. State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China; 2. China Electric Power Research Institute Beijing 100085 China
Abstract：In order to study the influence mechanism of dielectrically coated electrode in SF6 gas under DC electric field on metallic particle lift-off, experimental platform was setup and motion trajectory was recorded by high-speed camera. The experiment results showed that with the increasing of SF6 gas pressures, the lift-off field of metallic particle was increased and the time to reach the high-voltage electrode was shortened. Instantaneous displacement of metallic particle was gained on the basis of image processing and computational method of charge quantity was raised on the combination of dynamics equation and least square method,analyzing of charge quantity showed that the metallic particle’s charge quantity decreased. Meanwhile, theoretical analysis model of field distribution around metallic particle under dielectric coated electrode was established, analyzing of electric field indicated that there was a enhance of electric field between coating and metallic particle and a transform of charge density distribution, which leaded to a downward polarization force for metallic particle. Both the decreasing of the electric charge quantity and the downward polarization force result in the increasing of lift-off field. On the whole, this article maintains that partial discharge is the charging mechanism of metallic particle; the enlargement of SF6 gas pressure brings about the raise of initial electric field of partial discharge, causing the increase of downward polarization force with higher electric field to lift-off.
律方成, 刘宏宇, 李志兵, 董蒙, 颜湘莲. 直流电压下SF6气体中电极覆膜对金属微粒启举的影响机理[J]. 电工技术学报, 2017, 32(13): 239-247.
Lü Fangcheng, Liu Hongyu, Li Zhibing, Dong Meng, Yan Xianglian. Influence Mechanism of Dielectric Coated Electrodes on Metallic Particle Lift-Off in SF6 Gas under DC Voltage. Transactions of China Electrotechnical Society, 2017, 32(13): 239-247.
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2017, Vol. 32 
