变电站屏蔽电缆端口的雷电感应电压计算方法

变电站内屏蔽电缆容易受到雷电干扰,严重时会造成端接设备损坏,有必要开展电缆端口的雷电感应电压计算研究。基于电磁骚扰的耦合路径分析,提出了依次求解电缆屏蔽层响应和电缆内部响应的耦合分析步骤。对于电缆屏蔽层响应,指出了基于地电位差的传导耦合分析方法和基于空间磁场的感应耦合方法的不足,提出了基于电磁散射理论的更一般的分析方法;对于电缆端口响应,提出了基于转移阻抗和转移导纳的分布激励源的传输线计算方法。通过典型算例,计算了屏蔽电缆单端接地和双端接地时端口雷电感应电压,计算结果表明电缆屏蔽双端接地比单端接地具有更好地雷电屏蔽效果。

Calculation Method of Lightning Induced Voltage of Shielded Cable in Substation

Shielded cables in substation are vulnerable to lightning interference, which even cause serious damage to terminal equipment. It is necessary to carry out the research of lightning induced voltage in ports of shielded cable. Based on the coupling path, the coupling analysis process including the cable shield response and cable internal response are proposed. For cable shield response, the conductive coupling method and the inductive coupling method both have defects. A method based on electromagnetic scattering theory is proposed. For cable internal response, the TL method based on distributed exciting source is proposed. Through a typical example, lightning induced voltage in the ports of the shielded cable are calculated for both single-end grounding and double ends grounding. The calculation result shows a better shielding effect when double ends grounding.