双回线并列运行三相不平衡的分析研究

Analysis and Research on Unbalanced Three Phases in Parallel Operation of Double-Circuit lines

针对双回线并列运行时负荷电流不平衡,解列不平衡现象消失的问题,利用六序分量法进行了分析。分析出造成这种现象的原因是两回线参数不对称,在双回线中形成了环流不对称电流。当两回线解列运行时环流不对称电流消失,使得不对称现象不存在。以110kVⅠⅡ回线为研究,利用ATP-EMTP建立双回线模型进行了仿真,得到了负荷电流不对称的现象,并且通过仿真证明了并列运行时零序环流的存在,解列运行时环流电流为零,验证了分析的正确性。

Aiming at the imbalance of load current in parallel operation of double-circuit line and the problem of load current symmetry in solution operation,the six-component method is used to analyze in this paper.It is analyzed that the reason of this phenomenon is that the parameters of the two return lines are not symmetrical,and the circulating asymmetric current is formed in the double return line.When the two loop solves the asymmetric current circulation loop disappears,making the asymmetry does not exist.BY the example of Yunnan Lincang 110kV XinyunⅠⅡline,the double loop model was established by using ATP-EMTP and simulated.The load current asymmetry was obtained.The simulation shows that the zero-sequence current in parallel operation is zero,and the circulating current is zero during operation,which verifies the correctness of the analysis.