直流电场下涂层对导线表面水滴电致运动及电晕放电的影响

Effect of Coatings on the Electrostatic Motion of Water Droplets on the Surface of Conductors and Corona Discharges Under DC Fields

架空输电线路上的电晕放电现象通常由导线表面凸起物造成,如雨滴、污秽等,其中雨滴产生的电晕放电现象最为普遍。当前世界各国对于直流输电线路电晕放电机理的研究仍不够深入,因此其也成为发展高压直流输电亟待解决的问题之一。通过球板试验平台研究了涂敷涂层的铝球在表面附着水滴时,涂层对直流电晕特性及铝球表面水滴电致运动特性的影响;利用仿真软件建立了水滴电致运动多相流模型,分析了涂层接触角与水滴运动形态对水滴周围场强分布的影响。结果表明:水滴半径随接触角的增大而减小,水滴长度随接触角的增大先增大后减小;超亲水性涂层表面水滴吸附效应较强,水滴的运动幅度大大降低,水滴周围的电场强度畸变程度较小,同时电晕电流脉冲有效值最低;而超疏水性涂层表面的水滴难以稳定存在,水滴周围场强畸变程度较大,在电场作用下极易发生喷射现象,水滴喷射后场强的畸变程度会降低。

Corona discharge phenomenon on overhead transmission lines is usually caused by conductor surface projections,such as raindrops,dirt,etc.,of which raindrops produce the most common corona discharge phenomenon.At present,the research on the corona discharge mechanism of DC transmission lines is still not deep or enough in the world,thus,corona discharge has also become one of the problems to be solved for the development of high voltage DC transmission.In this paper,the ball-plate test platform was adopted to study the influences of coating of the aluminium ball in the surface layer attached to the water droplets on the DC corona characteristics,and the the droplets electroluminescent movement characteristics of aluminium surface were also investigated.The simulation software was adopted to establish the droplets electroluminescent movement of the multiphase flow model,and the coating contact angle and the droplet movement morphology on the droplets around the field strength distribution of the impact are analyzed.The results show that the droplet radius decreases with the increase of contact angle,and the droplet length increases and then decreases with the increase of contact angle;the droplet adsorption effect on the surface of the superhydrophilic coating is stronger,the motion amplitude of the droplet is greatly reduced,and the distortion degree of the electric field strength around the droplet is small;meanwhile,the RMS value of the corona current pulse is the lowest;it is difficult for the droplet to exist steadily on the surface of the superhydrophobic coating,and the distortion degree of field strength around the droplet is larger,which is very likely to occur under the electric field effect.Under the action of electric field,jetting phenomenon is very easy to occur,and the degree of distortion of field strength will be reduced after jetting of water droplets.