500kV同塔四回线路电气不平衡度的研究

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

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。

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.