XLPE电缆绝缘在线检测直流叠加法的接地

Study on the Grounding in Superposing DC Current Method for the On-line Monitoring of XLPE Cable

运用直流叠加法的XLPE电缆在线检测装置投入6～35kV系统后,将使系统中PT中性点以及电缆屏蔽层的接线发生改变。通过基于ATP-EMTP软件的仿真计算以及相关分析,针对故障状态下发生PT饱和谐振时,改接线对6～35kV中性点不接地系统可能产生的影响作出分析并找出相应的解决办法。

If the XLPE cable on-line monitoring system, which is based on the method of superposing a low DC voltage on the neutral point of PT ,is used in 6-35 kV power system, the way of grounding of potential transformers and the shielding layer of cable must be changed. Depending on simulations with the ATP-EMTP and some correlative analysis, the paper analyzes the possible effects on power system caused by changes of the grounding way when there is a fault caused by the over saturated windings of a potential transformer, and gives corresponding methods to solve the problems.