Surface Charge Inversion Calculation Method for Curved Surface Structure

When studying surface charge accumulation and dissipation law of insulating materials under HVDC transmission lines, the charge density can only be calculated by insulating materials surface electrostatic potential inversion. But it is difficult to accurately calculate the surface charge density when the insulating material surface is curved. In this paper, a charge density inversion method for curved surface is proposed. Potential measurement points are selected reasonably and intensively, and then curved surface is divided into triangular meshes according to the selected measurement points. The normal vectors at each point are obtained, and then the surface charge density is inverted. As an example, the surface potential of 3D printed curved surface and suspended insulator is measured, and the surface charge density is calculated. The calculated results are in accordance with the theoretical analysis trend. The electrostatic potential of insulating material surface has a strong correlation with the charge density, and the charge density corresponding to the high potential area is also large. The charge density presents a “concentric circle” distribution according to the distance from the discharge electrode. But the charge near the suspended insulator cap is difficult to accumulate and charge density is small.