Improved DC surface insulation performance of epoxy resin by gradient plasma fluorination

In order to improve the flashover voltage of the disc insulator in GIL under DC voltage, this paper considers reducing the electric field intensity on the surface by adjusting the surface conductivity distribution. Based on the joint simulation of improved PSO algorithm and finite element, the surface conductivity gradient partition optimization model is constructed to obtain the optimal surface conductivity distribution sequence. The relationship between conductivity and treatment time is obtained by plasma fluorination, and the gradient distribution of the surface conductivity of the sample is realized by adding different ring PTFE baffles. Microscopic tests are used to characterize the differences between different regions of the sample surface. The two-dimensional electric potential distribution, two-dimensional charge density distribution, electric field intensity distribution and flashover voltage on the sample surface under pre-charging condition are studied and compared with the simulation results. The results show that the maximum field strength of the sample with gradient treatment can be reduced by 71% and the flashover voltage can be increased by 45%. The research in this paper provides a good reference and theoretical support for the surface modification of disc insulators, such as the surface parameters with gradient distribution.