220kV同塔四回输电线路不平衡度分析及抑制措施研究

为了节约占地面积，减少电力系统成本，很多地区采用同塔多回线路的输电方式。但是采用同塔多回输电方式带来电压电流不平衡度问题，影响系统稳定性。本文介绍不平衡度计算方法。并针对220kV同塔四回输电线路，采用PSCAD/EMTDC仿真建模研究进行补偿，明显的降低不平衡度。通过研究可知：在长线路较大负荷下，零序电流与电磁穿越不平衡度是主要补偿对象；采取逆相序排列方式下，零序电流不平衡度依旧较大；在便于工程施工与较低不平衡度相结合的情况下，推荐采用同向三次换位方式进行同塔四回输电线路不平衡度补偿。

Study on Unbalance Degree and Suppression Measures of 220 kV Four-Circuit Transmission Lines on Same Tower

In order to save the area, reduce the cost of power systems, many areas with same tower multi-line transmission mode. But this mode bring the voltage and current unbalance degree, affecting system stability. This article describes the unbalance degree calculation method. For the 220 kV four-circuit transmission lines on same tower, PSCAD / EMTDC simulation modeling to compensate, significantly reduce the unbalance degree. By study found that: the Zero sequence current and through unbalance degree are the main compensation objects under the long line and heavy load; Zero sequence current unbalance degree is still relatively large using reverse phase sequence arrangement; In the case of ease of construction and low unbalance degree, It is recommended to use three times transposition method of Four-circuit transmission lines on same tower unbalance degree compensation.