交直流电缆共同敷设隧道内电磁场环境

Electromagnetic Environment in Utility Tunnel with AC and DC Cable

为分析交直流电缆共同敷设隧道内出现运维人员电麻痹的原因,基于有限元算法研究了±320kV直流电缆线路和220kV交流电缆线路共沟隧道内电场与磁场分布。首先计算交流在直流线芯以及护套上产生的感应电动势,确定交直流共沟敷设的可行性;其次计算隧道内磁场分布;再次利用高斯计以及对现场进行测量,并与仿真结果相比较;最后利用有限元迭代法确定了沙箱内空间电荷的累积量,分析运维人员发生电麻痹事故的原因。研究发现,隧道内高压直流侧磁感应强度高达1. 6 mT,这一数值大大超过了电缆隧道内磁感应强度的公众曝露极限值,而沙箱是导致这一现象的主要原因之一。

In order to analyze possible reasons for the phenomenon of electric paralysis that happened to the operation and maintenance personnel in the utility tunnel laid with AC and DC cable,the paper studies distribution of electric field and magnetic field in the tunnels with±320kV DC cable line and220kV AC cable line based on the finite element method.Firstly,it calculates induction potential in DC cable core and sheath which caused by AC cable and determines feasibility of AC and DC cables laying in the same tunnel.Secondly,it works out magnetic field in the tunnel,then uses the the Gauss meter to measure the field and compares the result with simulation result.Finally,by using the finite element iteration method,it determines accumulation of space charge in the sandbox and analyzes possible reasons for the phenomenon of electric paralysis.It has discovered that the magnetic induction of the HVDC side of the tunnel is as high as1.6mT,which greatly exceeds the limit of public exposure of the magnetic induction in the cable tunnel,and the sandbox is one of the main reasons for causing this phenomenon.