可调间隙防雷装置在35kV变电站防雷中的应用研究

针对广西某地区35 kV变电站的雷害事故,通过对变电站进线段采用的绝缘子进行U50%冲击闪络电压试验和现场调研,发现该地区变电站绝缘配合存在重大问题,线路绝缘水平过高,加之山区土壤电阻率高,导致雷电侵入波在线路上得不到充分的衰减,雷电能量缺乏泄放通道,致使35 kV主变雷击损害事故频有发生。为了解决该地区变电站的雷击问题,提出了在其进线段上加装并联可调间隙防雷装置和站内采用避雷器保护相结合的方案,着重分析了可调间隙防雷装置与绝缘子串绝缘配合方法及设计原则,基于上述思想进行理论计算和试验的方法,设计出适合本地区的可调间隙防雷装置间隙距离,最后利用电力系统电磁暂态程序ATP-EMTP模拟仿真。结果表明采用并联可调间隙防雷保护装置的可行性和有效性,同时针对间隙容易产生截波而且截波影响比较大的情况,采用变压器进线串接电抗器的方式,对截波过电压的影响有很好的抑制作用。

Application of Gap-adjustable Lightning Protection Device to Lightning Protection of 35 kV Substation

Aiming at lightning accidents in 35 kV substations in a certain region,U50% flashover voltage tests for the insulators on incoming line and field investigation were conducted,and severe defect in insulation coordination was found in the substations in this region,i.e.higher insulation level of transmission line and resistivity of the mountain soil cause the lightning invasion wave on the line not to attenuate sufficiently,and cause the lack of lightning discharge channel,which results in frequent lightning strike damages on the main transformers in 35 kV substations.In order to solve the lightning strike problem,a protection scheme is proposed in this paper by installing gap-adjustable lightning protection device in parallel on the insulators on incoming line and adopting arrester at substation.The insulation coordination of the device and insulator string as well as the design principle is analyzed,and the gap distance of the gap-adjustable lightning protection device for the region is designed through theoretical calculation and test.Simulation via the power system electromagnetic transient program ATP-EMTP shows that the gap-adjustable lightning protection device is feasible and effective.Considering that the gap is easy to induce clipped wave,which may significantly impact voltage,a reactor is concatenated to incoming line of transformer for inhibiting the effect of clipped wave over-voltage.