核电厂母线接地短路对二次电缆影响的研究

Analysis on the Impact of Ground Short Circuit on Secondary Cable in a Nuclear Plant

变电站发生母线接地短路故障时,会在屏蔽层双端接地的二次电缆屏蔽层上产生电位分布并在电缆与二次设备连接端口产生骚扰电压。通过CDEGS(Current Distribution,Electromagnetic Interference,Grounding and Soil Structure Analysis)建立了某核电厂的计算模型,基于矩量法计算了该核电厂GIL-GIS(Gas Insulated Transmission Line-Gas Insulated Substation)系统发生单相接地短路故障时二次电缆上产生的电磁骚扰,并分析了母线外壳的有无、外壳接地导体的数量以及短路点位置等相关因素对单相接地短路故障情况下二次电缆上的电磁骚扰的影响,得到了一些有益的结论。

During the ground short circuit failure on the bus in substation, potential distribution appears on shielding layer of secondary cables in two-terminal-grounding connection, and interference voltage is generated on the cable ports connected with secondary equipments. In the paper, the models of a nuclear plant built by CDEGS （Current Distribution, Electromagnetic Interference, Grounding and Soil Structure Analysis） is presented. The e- lectromagnetic interference on secondary cable results from the ground short circuit of GIL-GIS （ Gas Insulated Transmission Line-Gas Insulated Substation） system in the nuclear plant is calculated based on the method of moment. Some affecting factors such as the enclosure of bus-bar, the number of grounding conductor and the scene of ground short circuit failure are investigated. Some useful suggestions are proposed.