下穿铁路220 kV电缆爆炸原因分析

近年来,铁路运营里程不断创下新高,铁路线位选址与高压输电线路走廊的冲突无法避免。在某些特殊地形条件下,架空高压输电线路需改电缆下穿铁路。由于高压电缆结构复杂、敷设环境特殊,一旦在下穿铁路段发生爆炸将对周围设备及铁路运营安全造成严重威胁。针对某地220 kV电缆投切时发生爆炸这一情况,利用ATP⁃EMTP中的JMATI电缆模型建立了220 kV电缆投切过电压计算模型,结合故障录波图对实际合闸电压暂态过程进行了复现,考虑操作过电压的分散性,采用统计开关计算了电缆在该运行工况下可能出现的最高过电压倍数,结合计算结论对电缆爆炸原因进行了分析,认为造成电缆爆炸的原因应是电缆接头本身工艺或是安装问题,有必要对同种电缆接头质量进行进一步管控。采用的故障建模方法及校验过程也可为今后同类电缆故障的运行状态分析提供借鉴。

Cause of Traversing under Railway 220 kV Cable Explosion

Recently,the railway route length set another record high.Sometimes,the high⁃voltage cable has to be used to cross the railway.Due to the complicated structure and special application environment,it’ll cause great loss when explosion occurs to the high⁃voltage cable.Therefore,it’s necessary to analyze the failure reason of practical power cable.Based on the JMATI model in ATP⁃EMTP,the paper build the simulation model of 220 kV cables.The model can simulate the transient process of closing operation.The statistical switch is used to calculate the maximum overvoltage in this condition.The results show that the failure reason might be the defect of the cable joints’process and installation.The modeling methods can provide reference for the similar power cable failure.