220kV同塔双回线路雷击同跳事故仿真与闪络相分布

220 kV线路广泛采用同塔双回架设方式,在遭受雷击时容易引起2回线路同时跳闸,严重影响电力系统的可靠运行。首先分析了发生在丽水和宁波地区的2起220 kV线路雷击同跳事故的全过程,进而在EMTP程序上搭建了考虑接地电阻、感应电压分量等因素的计算模型。仿真研究结果表明：丽水象鹤/象睦线在幅值为-179 kA的雷电流下发生四相闪络事故和宁波晓昌/晓洲线在-140 kA的雷电流下发生的三相闪络事故均得到准确复现,雷电流幅值、工频电压相位与闪络发生相可以很好地吻合,模型的计算结果与实际情况一致。基于上述仿真模型,进一步研究了220 kV同塔双回线路同跳事故的闪络相分布规律,结果表明工频电压是决定同跳事故闪络相最关键的因素。

Lightning Multi-Tripping Accidents and Flashover Phases Distribution in 220 kV Double-Circuit Transmission Lines

The multi-tripping accidents often occur in 220 kV double-circuit transmission lines under lightning,which has serious influence on the reliability of power system. Firstly,two lightning multi-tripping accidents that happened in Lishui and Ningbo were analyzed. Then,the model with considering grounding resistance,induced voltage component and other factors was built based on EMTP program. The simulation results show that it can realize the accurate reappearance of the four-phase flashover accident caused by the lightning current with- 179 kA amplitude in Lishui Xianghe / Xiangmu line,as well as the three-phase flashover accident caused by the lightning current with- 140 kA amplitude in Ningbo Xiaochang / Xiaozhou line. The lightning current amplitude and the phase of power frequency voltage can be good match with flashover phases,and their values derived from the model match the real data perfectly. Based on the simulation model,this paper further studied the flashover phase distribution law of multi-tripping accidents in 220 kV double-circuit transmission lines. The results show that the power frequency voltage is the key issue that decides the flashover phases of multi-tripping accidents.