Dynamic Behavior of Condensation and Its Influence on Properties of Epoxy Resin Insulation

In high-humidity environments, condensation can adhere to the surface of the epoxy resin, resulting in partial discharge or even flashover along the surface. To solve the deterioration of the insulation properties of epoxy resin caused by condensation discharge, the morphological change and flashover process of water droplets under different voltage waveforms are studied, the effects of water droplets on the electric field strength and electron density of the insulation surface are simulated, and the surface conductivity of the epoxy resin, Fourier transform infrared spectrum and microscopic morphology after condensation discharge are analyzed. The results show that the morphology of water droplets is closely related to the type and strength of the applied electric field. The flashover occurs along the surface of water droplets, which causes electrical tracking corrosion on the insulation surface, decomposes epoxy resin to form hydroxyl and carboxyl groups, and increases the surface conductivity. The maximum field strength is located at the junction of epoxy resin, the water droplet, and air. The damage under the impulse voltage is weaker than that under the sinusoidal voltage and the direct current voltage. The distortion of the electric field distribution and the electron accumulation on the epoxy resin surface result from the water droplets and their deformation, which accelerate the flashover and further lead to irreversible deterioration of epoxy resin.