Field Domain Element And Boundary Element Coupling Method For The Integral Equation Of Insulator Electric Field

In recent years, with the continuous development of HVDC technology and flexible HVDC technology in our country, the structure of the HVDC converter valve tower is constantly changing. The insulator is an important part of the HVDC converter valve. And the electric field analysis of the converter valve is very important for the design of the HVDC converter valve.For the electric field in the insulator, the integral equation field domain element method was proposed in this thesis. The method was used to solve the integral equation of the potential in the dielectric. By use of Galerkin’s weighted residual method, the field is discretized into field domain elements. And the integral equation was discretized into algebraic equations. By solving the equations, the potential of the dielectric can be obtained. In order to avoid the singular integrals, the Galerkin weighted residual method was improved. According to the electric potential, the electric field inside the insulator can be obtained by the calculation of the gradient, and the electric potential and the electric field can be obtained by the integral calculation.The typical examples of the electrostatic field with analytical solution were selected. And the electric field and potential distribution inside and outside the dielectric were calculated by using the integral equation field domain element method. By comparing the numerical results with the analytical solution, the correctness of the integral equation field domain element method were verified.By use of Galerkin indirect boundary element method, the corona rings and the hardware at the ends of insulators were calculated and analyzed. For the system consisting of the insulator, hardware and corona rings, the integral equation field domain element and boundary element coupling method was proposed to calculate the electric field distribution of the insulator, hardware and corona rings by iteration.Taking the post insulator of a HVDC converter valve as an example, the electric field and potential distribution of the insulator was calculated. And the electric field distribution of the hardware and corona rings was calculated. The influence of the insulator on the electric field and potential distribution of the corona rings and the hardware at the ends of insulators was discussed. And the influence of insulator housing on the electric field and potential distribution of the insulator and corona rings and the hardware at the ends of insulators was discussed. The results show that without considering the insulator and ignoring the insulator has little effect on the electric field distribution of the corona rings. But there is a certain effect of the electric field on the interface of insulator and the hardware at the side of the ·high-voltage. It provides an effective way for the engineering practice to simplify insulators.