500 kV同塔四回线路电气不平衡度的研究

为有效提高单位走廊的输送容量,同塔多回路输电技术得到越来越广泛的应用,但是由于换位困难,一旦相序布置不当将造成线路电气不平衡情况更为严重。采用ATP-EMTP和MATLAB程序对500 kV同塔四回路3层横担和6层横担2种塔型的电气不平衡度展开了较为全面的研究。综合考虑负序电压电流不平衡度、杆塔的雷击跳闸率、电磁环境等指标,建议3层横担塔型采用推荐的相序布置方式、6层横担塔型上下两个双回路均采用逆相序布置。计算还表明,对500 kV同塔四回路,单回路停电检修时的感应电压和电流较高,选择接地开关时应予以特别关注。

Research on Electric Unbalance Degree of 500 kV Four Circuits on the Same Tower

In order to increase transmission capacity of electric power corridor significantly, multi-circuit on the same tower was constructed more and more widely in developed area. However, it’s difficult to realize transposition for multi-circuit on the same tower because of complex conductors arrangement, and electric unbalance degree of the transmission lines would get worse if phases were arranged inappropriately. ATP-EMTP and Matlab programs were applied to electric unbalance degree calculation for the three-layer and six-layer cross-arms tower of 500 kV four circuits on the same tower. According to the comparison of negative sequence voltage and current, lightning trip-out rate and electromagnetic environment, better electric unbalance degree was achieved when commendatory phase arrangement was adopted on three-layer cross-arms tower and diverse phase sequence was chosen on six-layer cross-arms tower. The results also showed that induce voltage and induced current from energized circuits got high when single circuit was maintained. It should be paid much attention to isolated switches selection.