Research On Surface Charge Characteristics Of Dielectric Film Under The HVDC Test Wire

High Voltage Direct Current(HVDC)system has its special advantages for long-distance and bulk-power transmission,the development of HVDC can help to optimize the allocation of resources,and solve problem of unbalanced energy resource distribution and economic development in China.And many HVDC projects have been built in latest several years in China.But with the increasing awareness of environmental protection,more and more people are concerned about the electromagnetic environment problem caused by HVDC transmission lines.In China,greenhouses are widely used in agricultural activities,when the greenhouse is close to the HVDC transmission lines,the charges generated by corona discharge would accumulate on the greenhouse and result in the distortion of the electric field around the greenhouse.With a lot of construction of HVDC transmission projects,HVDC transmission lines may pass over the greenhouses,and result in disputes.Researches on surface charge characteristics of dielectric film under the HVDC lines can help solve the practical problems.This paper mainly focuses on the factors that influence the surface charge characteristics of dielectric film.A set of experiments are performed in the laboratory,The surface potentials of dielectric film were measured by a vibrate capacitor electrometer,and the surface charge distributions of dielectric film were obtained by the surface charge method.The surface charge distribution characteristics of dielectric film under different condition are compared,and the factors that influence the surface charge distribution characteristics are discussed.The surface charge characteristics of PVC and PE film are also compared,and based on the detecting result of Atomic Force Microscope(AFM),the influence of material itself are discussed.Through a lot of experiments,this paper analyzes the factors that influence dielectric film surface charge characteristics from two aspects of internal and external.The research results of this paper lay the foundation for the experimental study on the real HVDC transmission lines.