线路避雷器提高超高压大跨越架空线路绕击耐雷水平的仿真研究

Simulation Research on Improvement of Lightning Shielding Level of Long Spans of EHV Overhead Lines by Installing Surge Arresters

为研究加装线路避雷器对提高超高压大跨越段绕击耐雷水平的有效性，参照官亭一兰州东750kV输电线路实际参数，建立了雷电流、输电线路、杆塔、绝缘子串和线路避雷器的EMTP-RV仿真模型，分析了不同雷击位置、不同避雷器装设方案、不同杆塔接地电阻对耐雷水平的影响。仿真结果表明：在跨越段两端各加装1组线路避雷器可将线路整体绕击耐雷水平提高至81～119kA，远远超过理论最大绕击雷电流30kA，并克服了接地电阻的影响，其中本基塔绝缘子被完全保护，但附近杆塔上绝缘子获得的保护作用有所弱化，若要实现完全保护，则需在跨越段两端及其相邻杆塔上都加装线路避雷器。

To study the effect of surge arrester installation on improving the lightning shielding level of long spans of EHV transmission lines, we established EMTP-RV simulation models of lightning current source, transmission lines, towers, insulator strings, and line an＇esters based on the actual parameters of Guanting-East Lanzhou 750 kV transmission line. Factors, such as grounding resistance, location of lightning, distribution of surge attesters installation, which could affect the minimum shielding failure current to cause flashover, were analyzed. The simulation results show that installing surge attesters at each end of the long span to three phases significantly improves the lightning shielding level to 81-119 kA, which is far beyond 30 kA, the theoretically calculated maximum shielding failure current. This setting of surge ar- resters also conceals the influence of grounding resistance variation. While the insulators at each end of the long span are fully protected, the protection of insulators on nearby towers is weakened. To achieve a full protection, additional surge arresters should be installed on the adjacent towers.