Study on the Influence of the Inclination Angle of the Insulator on the Deformation and Flashover Behaviour of Water Droplet under AC Field

The separation of water droplets on the insulator umbrella surface is an important factor that increases the probability of flashover along the surface. Previous studies have only investigated the motion and deformation of water droplets on the horizontal insulator sample surface and their effect on flashover voltage. In actual composite insulators, the umbrella skirt surface is usually inclined at a certain angle. The influence of the umbrella angle on the motion law and flashover voltage of water droplets has not been fully studied in recent research. In this paper, focusing on the separated water droplet on insulator sample surfaces with different inclination angles, the motion modes and flashover characteristics of the water droplet are studied by using multi-physics finite element simulation and AC flashover experiment. The results show that the motion modes of water droplets change with the inclination angle of the umbrella surface. The water droplet oscillates left and right under the AC electric field when the inclination angle is small. As the inclination angle increases, the oscillating trend of the water droplet weakens. When the inclination angle is large enough, the deformation of the water droplet shows two forms: sliding and stretching. As the inclination angle of the umbrella surface increases, the flashover voltage decreases, and the decreasing trend of the flashover voltage is greater when the inclination angle is larger.