Study On The Influence Of Surface Roughness On The Surface Charge Of PMMA Under DC Voltage

Polymer dielectrics are commonly used as insulating materials in high-voltage electrical equipment due to their excellent insulation and mechanical properties.The surface of polymer is easy to accumulate charge under the DC voltage,which affects the electric field distribution,even cause the surface flashover.The correlation between the dielectric surface morphology and surface charge is not clear.Therefore,exploring the relationship between the dielectric surface morphology and the surface charge is important to ensure the safe and stable operation of the power system.This work intends to carry out research on the effect of surface roughness of polymethyl methacrylate(PMMA)on surface charge under DC voltage.The specific contents are as follows:Based on different mesh sandpaper,polished the surface of PMMA by random grinding and directional grinding.And the surface roughness measuring instrument was used to test the material surface roughness in the process of polishing to obtain order texture or random texture of different surface roughness of samples.On the basis of the original equipment of the research group,the surface potential measuring platform of electric controlled was built by refitting and adding device.The surface of PMMA was charged by corona of pin-plate electrode.The surface potential was measured by the surface potential measurement platform.The effects of surface roughness,polishing orientation,charge polarity and dissipation time on the surface potential distribution of PMMA were investigated.The effects of surface roughness on the surface properties of materials were further analyzed by the total surface charge and dissipation rate.The surface roughness of PMMA was simulated by MATLAB,and the MCC-PIC simulation model was established.The simulation of the surface charge accumulation of PMMA was carried out under vacuum environment based on the principle of secondary electron emission avalanche.Single particles were observed,and then the accumulation of surface charge taken into statistics.The influence of the voltage amplitude on the same roughness and the influence of the two electron emission rate on the surface charge accumulation were further simulated.