Analysis of Microscopic Process of Insulator Fittings for DC Transmission Lines

Electrical corrosion of fittings is a persistent problem of porcelain and glass insulators on HVDC transmission lines. In order to study the microscopic process of the corrosion of insulator fittings in DC transmission lines and reveal the key factors for the corrosion of insulator fittings under the action of a strong DC electric field, this paper established the bottom glass experimental model and the bottom ceramic sheet experimental model under bar board voltage, and built a proportional simulation model to analyze the voltage distribution of the corresponding material. The test principle of the experimental model of the bottom glass under the pressure of the rod plate is based on the depolarization potential detection method. The sample solution of different concentrations is pressurized for different times. After short-circuiting, the relationship between the residual voltage at both ends of the electrode and time is measured and analyzed the influence of an external DC electric field on the depolarization potential of the rod-plate electrode. The test principle of the experimental model of the bottom ceramic sheet under the pressure of the rod plate is based on the external electric field affecting the ion migration in the solution, and the ion migration in the solution will cause the local concentration to change, and the conductivity of the electrolyte solution is related to the concentration of the solution. The relationship between the electric field and the conductivity of the solution, and the mechanism of the applied electric field on ion migration is analyzed. The experimental results show that under the action of a DC electric field, the depolarization potential at both ends of the rod-plate electrode connected to the sample will change with the applied voltage time, but the change trend is the same. There is ion migration in the solution; under the action of the DC electric field, Different pressurization time will cause the internal conductivity of the solution to change.