后续雷击对输电线路绕击耐雷性能的影响研究

为分析负极性后续雷击对输电线路绕击耐雷性能的影响,采用电磁暂态程序计算绕击耐雷水平、改进电气几何模型计算线路绕击跳闸率的方法,研究了首次雷击、与首次雷击相同以及不同回击通道的后续雷击下雷电流波形和幅值分布、杆塔高度和地线保护角对典型结构的110、220、500和1 000kV输电线路绕击耐雷性能的影响.结果表明:后续雷击的电流分布对线路绕击跳闸率影响极大,而后续雷电流波形影响很小;异回击通道后续雷击对500kV以下线路的绕击跳闸率影响很大,而对特高压线路影响较小;500kV线路有必要考虑后续雷击的影响;在线路首次雷击和异回击通道后续雷击绕击跳闸率为0的情况下,同回击通道后续雷击仍可能造成绕击跳闸.

Impact of Subsequent Strokes on Lightning Shielding Failure Outage Rate of Transmission Lines

Abstract： The lightning shielding failure withstand current and outage rate (SFOR) of typical single circuit type 110 kV, 220 kV, 500 kV and 1 000 kV transmission lines caused by the first stroke, subsequent stroke through the same and different return stroke channels with first stroke was analyzed based on EMTP and improved electro geometric model (EGM). The effect of peak current distribution and waveform, tower height and shielding angle were analyzed. The results show that the peak current distribution of the first and subsequent stroke has a significant impact on the SFOR while the current front time of the first and subsequent stroke has little effect. The subsequent stroke of  different return stroke channel has a significant impact on the transmission line with a voltage class of less than 500 kV but has little influence on the UHV transmission line. The effects of subsequent stroke of the 500 kV transmission line is worth considering. In the condition of none SFOR owing to the first stroke and the subsequent stroke of different return stroke channel, the SFOR may still occur due to the same subsequent stroke of the return stroke channel.