模拟火灾条件下高压电缆绝缘击穿试验研究与失效时间分析  

Test study and failure time analysis of insulation breakdown of power cables under simulated fire conditions

作　　者：郭卫 周士贻 门业堃 普子恒[2] Guo Wei;Zhou Shiyi;Men Yekun;Pu Ziheng(State Grid Beijing Electric Power Research Institute,Beijing 100075,China;College of Electrical Engineering&New Energy,China Three Gorges University,Hubei Yichang 443002,China)

机构地区：[1]国网北京电力科学研究院,北京100075 [2]三峡大学电气与新能源学院,湖北宜昌443002

出　　处：《消防科学与技术》2023年第5期627-632,共6页Fire Science and Technology

基　　金：国网北京市电力公司科技项目(520223200069);国家自然科学基金青年基金项目(51607103)。

摘　　要：高压电力电缆结构复杂,在火灾情况下绝缘的失效时间与低压线缆有较大差异。本文首先搭建模拟火灾试验平台,对110,10 kV阻燃电缆开展模拟火灾情况下的绝缘耐压击穿试验,记录绝缘失效时间、解剖分析内部情况;然后建立三维仿真模型分析火灾情况下电缆内部绝缘层温度变化;参考绝缘层材料高温下的击穿场强,结合仿真和试验分析高压电缆在火灾情况下的绝缘失效机理。结果表明:火灾情况下高压电缆绝缘层在击穿前软化熔融,金属护套发生破裂有熔融物滴落,110、10 kV电力电缆在200 kW火源功率下的绝缘失效时间分别约为130 min和60 min。仿真得到110 kV电力电缆绝缘层的熔融时间约为25 min,击穿时刻均温约为378℃。放电在熔融的绝缘层内部逐步发展最终形成击穿,绝缘失效时间不能以单一的绝缘材料失效温度确定,与绝缘结构和温升变化相关。The structure of high-voltage power cables is complex,and the insulation failure time is different from that of low-voltage cables under fire condition.Firstly,the fire test platform is built in this paper.The insulation withstand voltage breakdown test of 110 kV and 10 kV flame-retardant power cables under fire conditions is carried out.The insulation failure time is recorded,and the internal condition of the cable is dissected and analyzed.Then a 3D simulation model is established to analyze the temperature change of the insulation layer inside the cable under fire.Referring to the breakdown field strength of insulating layer material at high temperature,the insulation failure mechanism of high-voltage cable under fire is analyzed in combination with simulation and test.The results show the insulation layer of high-voltage cable softens and melts before breakdown under fire condition.The metal sheath breaks and the melt drops.The insulation failure time of 110 kV and 10 kV power cables under 200 kW fire source power is about 130 min and 60 min,respectively.The simulation results show that the melting time of insulation layer of 110 kV power cable is about 25 min,and the average temperature of breakdown time is about 378℃.The discharge develops gradually in the molten insulation layer and finally forms breakdown.The insulation failure time can not be determined by a single insulation material failure temperature,which is related to the insulation structure and temperature rise change.

关 键 词：高压电缆 击穿试验 模拟火灾 温度 绝缘失效 

分 类 号：X913.4[环境科学与工程—安全科学] TU990.3[建筑科学—市政工程]