Study on Surface Electric Field Distribution Characteristics of Polluted Composite Insulator for ± 800 kV Transmission Line

Under the example of ±800 kV DC composite insulator sample model which provided by southern power grid technology center in this paper. To calculate the surface electric field distribution characteristics and surface current density and umbrella voltage, a series of three-dimensional electric field calculation models was established by changing the composite insulator surface filth type and the setting of pollution levels of the composite insulator. The results show that the electric field distribution on the surface of the composite insulator under uniform wet pollution is generally linear along the voltage distribution on the surface of the insulator, but the voltage distribution on the surface of the insulator is locally uneven due to the uneven diameter of the insulator's umbrella skirt and pole diameter. When the pollution turn into wet, the voltage and electric field distribution characteristics of the composite insulator are seriously distorted. The current density of the part with small diameter of composite insulator is large, and the current density distribution on the whole composite insulator changes in an overall cycle according to this law.