Simulation Study on Discharge Process of Negative Polarity in UHV Tower-line Air Gap

Carrying out the research on the physical simulation model of the negative polarity discharge process in UHV tower-line air gap is of great significance to the lightning protection of UHV transmission lines. Based on the physical mechanism of negative discharge in long air gap, a physical simulation model including initial corona initiation and streamer development, leader initiation, streamer-leader system development, and final jump is established. The model considers the characteristics of corona initial development, the randomness of the leader path, and the negative development of the negative leader. Finite element software was used to calculate the background potential distribution of the gap, and the experimental observations were used to verify the model established in this paper. Finally, the model was used to simulate the discharge process of the negative polarity in tower-line air gap under actual size of tower window structure. The results show that the simulation calculations agree well with the test results.