Shape and Evolution Mechanism of Insulator Local Arc Based on Energy Level Transition

Insulation pollution flashover is one of the most common faults on the transmission and distribution lines, but a comprehensive theoretical explanation of the discharge mechanism and accurate prediction methods are lacking because of its complex surface discharge mechanism and numerous influencing factors. Current research mainly uses macroscopic analysis approaches such as empirical formulas and experimental testing, which cannot fully reveal the discharge mechanism of the formation and development process of local arc. To address this, this article introduces the energy level transition theory to calculate the critical condition for the development process of local arc and establishes a force analysis model based on the chain arc theory. Using this model, the evolution process of local arc shape is studied, and the effects of applied voltage, pollution degree, wind velocity, and wind direction on the floating arc shape are analyzed. In the validation experiment, the experimental values of the critical leakage current, local arc development time, and limit arc floating degree are consistent with the theoretical values. The research results can reveal the flashover mechanism of polluted insulation surface and provide theoretical support for accurate fault prediction and efficient operation and maintenance of power transmission and distribution equipment.