Abstract: In response to the unclear impact of vegetation size on the characteristics of high impedance ground fault (THIF) caused by wire tree contact and the difficulty in predicting ignition, this article deeply analyzes the ignition phenomenon and the variation of leakage current during the THIF fault process. Explored the relationship between different vegetation sizes and leakage current, and studied the influence of vegetation size on arc discharge characteristics at tree line contact positions. On this basis, the numerical relationship between vegetation size parameters and leakage current was derived, and a leakage current prediction model at open flame time was established that comprehensively considers vegetation diameter and length. The research results can provide important basis for vegetation management and mountain fire prevention in distribution line corridors.

Key words: wire contact tree, high resistance ground fault, leakage current, vegetation size, prediction model