Insulation Property of Wire-plane Gap under Fire Condition: Effects of Vegetation Flame Conductivity

摘要

Energy distribution and economic development level of our country are imbalance, and a large number of EHV and UHV transmission lines pass through high forest fire risk zone, and insulation property of transmission under mountain fire condition is a critical issue needed to be considered during survey, design and operation and maintenance. Gap discharge under mountain fire condition is affected by high temperature, flame conductivity (electron and ion) and large particles (smoke fog and ash), etc. This article studied characteristics of leakage current of different vegetation flames and the effect of flame conductivity on wire-plate gap breakdown characteristics with the sample of typical vegetation that causes line trip under transmission line. Research result show that conductivity of three kinds of typical vegetation flame is quite high, breakdown voltage is decreased obviously with rising of flame conductivity, and discharge pattern is transited from streamer discharge lead to electric arc discharge. Discharge characteristic of different vegetation flames can be identification basis of mountain fire risk region and dangerous vegetation, which improves reliability of line under mountain fire condition.