745 / 2022-03-31 20:35:56

Experimental study on the influence of wildfires on 35kV transmission lines and their insulation characteristics

fire; 35kV transmission lines; insulation characteristics

Experimental study on the influence of wildfires on 35kV transmission lines and their insulation characteristics

Yang Jiacai, Li Weijia, Chen Tianxiang, Yang Nongchao, Yang Chunlan

Chengdu University of Technology

897015066@qq.com

Purpose/Aim

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. It is imperative to study the changes in insulation characteristics of transmission lines under wildfire conditions.

Experimental/Modeling methods

In this paper, we design and build a test research platform for the impact of wildfire on the safe operation of 35kV transmission lines and a test model of flame-affected gas gap breakdown voltage, use wood stack fire to simulate wildfire conditions, study the three-phase voltage of transmission lines under mountain fire conditions, the leakage current of wires to the ground, and the variation characteristics of open triangle voltage, study the influence of flame on breakdown voltage, and study and analyze the effects of flame temperature, flame height, etc. on the insulation of 35kV transmission lines.

Results/discussion

Wildfires can cause single-phase grounding and phase-to-phase short circuits in transmission lines, and single-phase grounding and phase-to-phase short circuits are the result of the combined action of temperature and flame.

Conclusions

1)The size of the breakdown voltage is inversely correlated with the temperature, and the flame as a plasma bridge pole can significantly reduce the breakdown voltage. Both flame and temperature are the main factors affecting the breakdown voltage.     2) Zero-sequence voltage and leakage current are related to temperature and fire potential; the phase voltage affected by the wildfire is not the lowest compared with other phase voltages, which makes it difficult to identify the selected line of the mountain fire fault.