Condensation model and corona inception characteristics on the surface of insulating material under high humidity and high pollution conditions

In recent years, the problem of surface discharge of insulating materials caused by condensation and pollution has become prominent. Therefore, it is of great significance to study the discharge initiation characteristics of insulating material surfaces under wet and dirty conditions to improve the operational reliability of electrical equipment. Firstly, based on the existing condensation growth model, a condensation growth model considering the influence of the surface contamination layer is established, and the visualization dynamic image of the whole process of condensation growth is realized by MATLAB software programming. Secondly, the physical model of a single droplet on the surface of the epoxy resin plate was constructed using COMSOL software and the electric field distribution on and around its surface was calculated. Models with different plate spacing, dewdrop radius, contact angle, and droplet spacing are simulated, and the influence of these factors on the electric field distribution along the surface is analyzed. Then, based on the photoionization criterion, a prediction model of the negative DC corona onset voltage considering temperature and humidity is proposed, and the corona onset voltage under the above conditions is predicted and analyzed. Finally, relevant corona onset experiments were carried out to verify the validity of the prediction method of negative polarity DC corona onset voltage.