海上升压站主变直击雷过电压仿真计算

Simulating Calculation of Lightning Overvoltage on Main Transformer in Offshore Substation

依据某海上升压站设计实例,主变压器油枕暴露于屏蔽室外,有遭受雷击的可能。本文借助ATP/EMTP电磁暂态仿真软件,分别建立变压器外壳-绕组模型、套管闪络模型和海缆模型,并综合考虑雷电流幅值、海上平台接地电阻等影响因素,研究雷直击主变油枕时产生的过电压对站内设备的影响,校验已有设计方式下低压端设备的绝缘裕度。结果表明:通过加强主变套管绝缘可以降低该种形式的雷电侵入波对站内设备的过电压影响;通过在主变绕组低压侧出口处及集电海缆两端各装设一组避雷器可确保站内设备具有一定的保护裕度,但是绕组低压侧还需加强保护。仿真结果为海上升压站的雷电侵入波保护设计提供了参考。

According to the offshore substation layout, the main transformer conserver was exposed and was likely to be stroke by lightning. Thus ATP/EMTP was used to model the transformer, bushing flashover and undersea cable, and by considering both lightning current amplitude and ground resistance of offshore platform, a study on the overvoltage of substation devices when lightning stroke the transformer conserver was carried out, then the insulation margin of low voltage devices was checked. The result showed that, by reinforcing the insulation of main transformer bushing, the lightning intruding overvoltage of devices in the substation will decrease. By installing lightning arresters in low voltage side of the main transformer and both sides of undersea cable, the devices in the substation will be under good protection, while further measures should be taken for the low voltage side. The result will be reference for the lightning inrush overvoltage protection of offshore substation.