一种基于 PSCAD/EMTDC的同塔四回输电线路三相不平衡最优相序筛选方法

同塔双回输电线路采用逆相序排列方式可以很好地解决三相电流不平衡的问题，而同塔四回输电线路的三相不平衡问题要复杂得多，不能简单地采用逆相序排列方式。为此，首先分析了同塔四回输电线路三相不平衡产生的原因，然后利用 PSCAD/EMTDC软件对同塔四回输电线路不同的相序排列方式进行了仿真研究；搭建了基于Multiple-Run模块的同塔四回输电线路最优相序筛选模型，给出了相应的程序流程图，通过该模型可以计算不同目标函数下的最优相序。最后以广东揭阳电网某220 kV和500 kV同塔四回输电线路三相电流不平衡问题为例，利用提出的模型和方法，推荐了最优相序改造方案；该方案已被采纳实施，取得了较好的效果。

Screening Method for Optimal Phase Sequence of Three Phase Unbalance of Quadruple Circuit Power Transmission Line on the Same Tower Based on PSCAD/EMTDC

It is able to well solve problem of three phase current unbalance by using inverse phase sequence arrangement for double circuit power transmission line on the same tower while it is more complicated for three phase unbalance for quadrup-le circuit power transmission line on the same tower which means unable to simply use inverse phase sequence arrangement way. Therefore,cause for three phase unbalance of quadruple circuit power transmission line on the same tower was ana-lyzed and simulation studies on different phase sequence arrangement ways were conducted by using PSCAD/EMTDC soft-ware. Optimal phase sequence screening model for quadruple circuit power transmission line on the same tower based on Multiple-Run module was established by which optimal phase sequence under different target functions were able to be calcu-lated. Meanwhile,relevant program flow diagram was proposed. Taking three phase current unbalance of some 220 kV and 500 kV quadruple circuit power transmission lines on same towers in Guangdong Jieyang power grid as examples and using proposed model and method,optimal phase sequence transform scheme was recommended which was adopted and implemen-ted and proved to be of good effectiveness.