摘要
500 kV红甲线、红乙线发生同时跳闸故障,重合成功。经现场故障特巡,发现甲线#88塔C相(上相)和乙线88塔C相(下相)绝缘子串及防震锤有明显放电痕迹。查询电网雷电监测系统故障时段500kV红甲线#88-#89附近有一次250.6 kA主放电,判断本次跳闸故障由雷击引起的嫌疑较大。对#88塔计算分析可知,其单回跳闸反击耐雷水平为176 kA,双回同时跳闸反击耐雷水平为213 kA,而故障时刻250.6 kA的正极性落雷高于双回反击耐雷水平,且故障时刻C相电压为负值,电压差最大,最容易击穿,详细仿真计算也表明了正极性250.6 kA雷电流将造成双回C相同时跳闸,因此得出此次故障由于超大正极性雷电流反击造成。从线路设计规程和过电压配合标准对照来看,500 kV红甲乙线满足设计防雷要求,同时其运行耐雷水平和跳闸率指标也满足国标要求。可见,本次雷击同跳属于小概率事件,但从保障电网安全稳定考虑,后续建议对主网架重要500 kV线路的雷击高风险杆塔适当降低杆塔接地电阻、提高绝缘配置,从而提升双回反击耐雷水平,保障输电通道安全性。
500 kV Hong line A and line B tripped at the same time, and the reclosing was successful. Through the special accident patrol, It is found that there are obvious discharge traces on the insulator strings and shock absorbers of phase C(upper phase) of tower # 88 of line a and phase C(lower phase) of tower 88 of line B. Through the power grid lightning monitoring system, there is a 250.6 kA main discharge near 500 kV Hong line A #88-#89 during the fault period. it can be seen that the trip fault is highly suspected to be caused by lightning. According to #88 tower lightning withstand performance calculation results, the lightning withstand level of single circuit tripping and counterattack is 176 kA, and that of double circuit simultaneous tripping and counterattack is 213 kA.According to the lightning location system, the positive polarity of lightning falling at the time of fault is 250.6 kA, which is higher than that of double circuit counterattack, and the phase C voltage at the time of fault is negative, with the largest voltage difference and the easiest breakdown, The detailed simulation calculation also shows that the positive lightning current of 250.6 kA will cause the tripping of phase C of line a and phase C of line B at the same time. Therefore, it is concluded that the fault is caused by the counterattack of super positive lightning current. From the comparison of line design regulations and overvoltage coordination standards, 500 kV Hong line A and B meets the design lightning protection requirements, and its operation lightning resistance level and tripping rate also meet the requirements of national standards..It can be seen that the lightning strike and the same jump belong to small probability events. However, from the perspective of ensuring the safety and stability of the power grid, it is suggested to appropriately reduce the grounding resistance and improve the insulation configuration of the high-risk poles and towers of the important 500 kV lines of the main grid, so as to improve the light
作者
梁健
张杰
Liang Jian;Zhang Jie(Yunnan Power Grid Co.,Honghe Power Supply Bureau,Mengzi,Yunnan,661100)
出处
《云南电力技术》
2022年第6期93-95,共3页
Yunnan Electric Power
关键词
同塔
雷击
防雷
double circuit
lighting strike
lighting protection
