±660kV直流输电线路反击耐雷性能研究

Lightning Withstand Performance Research of Back Strike for ±660 kV HVDC Transmission Line

在现有输电线路防雷研究成果的基础上,基于ATP-EMTP建立了计算±660 kV直流输电线路反击耐雷水平的模型,模型中杆塔采用多波阻抗模型,绝缘子闪络判据采用相交法,雷电波采用双指数波形,考虑导线电压的影响。所建模型经过验证后,首先分析了杆塔高度和接地电阻对输电线路反击耐雷水平的影响,然后以±660 kV输电线路典型塔形ZP2711为例分析了雷电反击对塔顶电位以及绝缘子两端电压的影响。研究表明,降低冲击接地电阻比降低杆塔高度能更有效地减小线路的反击耐雷水平,±660 kV线路在普通地形段的耐雷水平达232 kA,在大跨越段耐雷水平降低到175 kA,因此在大跨越段应加强接地电阻排查,以防由于接地电阻增大进一步降低线路的耐雷水平,从而引起反击闪络。

On the basis of previous research about transmission line lightning protection, the model of calculating ±660 kV transmission line lightning back strike withstand level was established using ATP-EMTP. In the model, the multi-wave impedance model was adopted for the tower, the intersect method was adopted for the insulator flashover criterion, the double exponential wave was adopted for the lightning current, the conductor voltage was considered also. After the established model was verified, the impact of tower height and impulse ground resistance to the transmission line lightning back strike withstand level was analyzed firstly. Furthermore, the influence of lightning back strike to the voltage of tower top and insulator was investigated. It is shown that decreasing the ground resistance can more effectively improve the transmission line lightning withstand lever than decreasing the tower height. The ±660 kV transmission line lightning back strike withstand level was 232 kA in the common part, and 175 kA in the long span part. Therefore, the inspection for ground resistance in the long span part should be strengthen to prevent lightning withstand level decrease leading to lightning back strike flashover due to the ground resistance increase.