Experimental Study on the Influence of Wildfires on the Insulation Characteristics of 35kV Transmission Lines

In recent years, transmission lines have been affected by wildfires and tripping frequently, which has seriously affected the safe and stable operation of the transmission network. In this paper, an experimental research platform was designed and built on the impact of wildfire on the safe operation of 35kV transmission lines, a flame-affected gas gap breakdown voltage test was designed and built, a simulated mountain fire was lit by using a wooden stack fire, the characteristics of the three-phase voltage of the transmission line, the leakage current of the wire to the ground, and the opening triangular voltage change characteristics of the transmission line under the conditions of the mountain fire were studied, the effect of the flame on the breakdown voltage was studied, and the effect of flame temperature, flame height, plasma, etc. on the insulation of the 35kV transmission line was studied. Experimental results show that wildfires can cause single-phase grounding and phase-to-phase short circuits of transmission lines, and single-phase grounding and phase-to-phase short circuits are the result of the combined action of temperature and flame, of which temperature and flame are the main factors causing breakdown. The phenomenon that the transmission line discharges the flame and the voltage of a certain phase affected by the flame is significantly lower than that of other phases during the test process is studied, and the reasons and laws of the influence of the wildfire on the 35kV transmission line are obtained. This paper provides a reference for the follow-up study of the fault mechanism of 35 kV transmission lines caused by wildfires and the proposed corresponding protection measures.