改进先导模型法交流特高压线路雷电屏蔽性能分析

Analysis of Lightning Shielding Performance of 1000 kV UHV AC Transmission Lines Based on Improved Leader Progression Model

先导传播模型法已被用于超高压线路雷电屏蔽性能的分析,对特高压交流输电线路,由于其本身的特殊性和高度重要性,先导传播模型法的应用仍值得研究。针对特高压交流输电线路的实际情况,提出进一步改进多分裂导线的先导起始判据,建立特高压交流输电线路绕击性能分析的改进先导传播模型法。考虑晋东南-南阳-荆门1000kV线路走廊所处位置的雷电活动特性,对特高压试验示范工程采用的4种塔型进行了绕击性能分析。考虑到特高压交流输电线路对安全运行的严苛要求,还对特高压输电线路进行了局部屏蔽分析。研究表明,与500kV超高压交流输电线路相比,特高压输电线路的绕击侧距和绕击电流明显变大。按初步设计的特高压交流输电线路在平原地区应不会发生绕击跳闸,拟用于山区的ZBS1和ZBS2型杆塔的线路绕击率最大为0.0012次/(100km·a),满足线路的设计要求。作为对比,拟用于平原的ZMP1和ZMP2型杆塔如用于山区,则绕击跳闸率可达约0.17次/(100km·a)。考虑到实际线路弧垂的影响,同一输电线路不同位置线路段的局部绕击性能也不相同,对于重要和特殊线路段建议进行局部屏蔽性能的复核。

An improved leader progression method （LPM） based on long gap discharge studies has been applied in the analysis of lightning shielding performance for EHV transmission lines. Because of the specificity and great importance of UHVAC transmission lines, the application of LPM in UHVAC transmission lines needs further studies. Considering the practical characteristics of UHVAC transmission lines, an improved LPM is proposed in this paper in which the leader inception criteria of the bundled conductors are modified. The shielding failure performance of the UHVAC transmission line of the Chinese Test Model Proiect with four types of towers is calculated. The lightning activity parameters in the right-of-way of the transmission line are adopted in the calculations. Partial shielding performance at different segments in a line span is also investigated considering the strict safety requirement of the UHVAC transmission lines. The research indicates that the side-distances and lightning currents of shielding failure for UHV transmission lines are obviously bigger than that for 500 kV EHV lines. The UHVAC line should be free of shielding failure brip-out under flatter terrain conditions. Undeer slope terrain condition, the maximum shielding failure trip out rate of ZBS1 and ZBS2 towers （slope-terrain-type tower） is only 0. 0012 times/ （100km·a）, which fulfills the design requirement. As a comparison, if the ZMP1 and ZMP2 towers （flat-terrain type tower） were applied in slope terrain area, the shielding failure trip-out rate will reach 0. 17 times/（ 100km·a）. Considering the influence of the line sag, partial shielding failure performances at different segments in the same span are different, It indicates that the partially shielding failure performance analysis is necessary for important and special transmission line parts.