特高压交流输电线路雷电流监测

Observational Technique of Lightning Current Striking to UHVAC Overhead Transmission Line

为了掌握特高压(UHV)线路雷击故障的类型以及击于线路的雷电流幅值和极性,进一步优化我国特高压架空输电线路防雷设计,采取了在特高压交流示范工程输电线路上广泛布置磁钢棒的雷击电流监测方法。即在每基塔的塔顶地线羊角处安装引雷针,并在引雷针和杆塔两侧地线上分别布置6个测点,每个测点采用磁钢棒来记录雷击电流,并通过与雷电定位系统相结合提高雷击故障杆塔的定位效率。试验测试和理论分析表明,通过在6个测点安装新研制的具有涡流损耗更小、灵敏度更高、稳定性和线性度更好等优点的新型磁钢棒获取雷电流幅值和方向,可直接判别出线路雷击故障类型;另外,通过与仿真计算相结合,可推算出线路绕击雷电流的幅值以及雷击塔顶和档距中央避雷线的雷电流幅值,从而可以更高效、准确地判别出特高压线路雷击故障的类型以及击于线路的雷电流幅值和极性。

For the sake of differentiating shielding failure trip from back stroke trip and observing the amplitude and polarity of the lightning stoke current, so as to realize the further optimization on lightning protection calculation method and design of China UHVAC overhead transmission line, we put forward a lightning observation method suitable for UHVAC overhead transmission line by widely arranging magnetic steel sticks. We installed two lightning rods at the top of each transmission tower, and placed magnetic steel sticks on each rod and on ground wires of both sides of each tower, namely, six points in total per tower, to measure lightning current. Furthermore, the location efficiency was improved by combining lightning strip towers with lightning location system. Test results indicate that the new type of magnetic steel sticks have less eddy current loss, higher sensitivity, better stability, and larger linearity scope. According to the amplitude and flow direction of the lightning curent measured by the new type of magnetic steel sticks, and combining with simulation calculation, we can .not only differentiate shielding failure trip from back stroke trip and observe the amplitude and polarity of the lightning stoke current, but also define the location of lightning stroke on the line and the distributary coefficient of the tower.