基于外网等值模型的输电线路不平衡度计算方法

摘要

More and more attention is paid for degree of unbalance of power transmission lines due to continuous increases of double-circuit lines or multi-circuit lines on the same tower and untransposition lines,therefore,this paper studies key prob-lems about calculation on degree of unbalance of power transmission lines in aspect of equivalent model of the outer power grid.On the basis of parameters of equivalent impedance of the outer grid provided by power system department-short cir-cuit current program (PSD-SCCP)widely used in domestic,the equivalent model of the outer grid is constructed,method for getting equivalent parameters is provided and from this it is able to get more understanding equivalent parameters of the out-er grid with more clear physical meanings.According to the above equivalent model,accurateπtyped equivalent circuit is used to calculate degree of unbalance of lines.Comparison between results of calculation and simulation indicates that the proposed calculation method for degree of unbalance has excellent veracity and relevant conclusion has been applied in actual engineering.%同塔双回、多回及未换位线路不断的增加,使得输电线路不平衡度越来越受到重视,为此从系统外网等值模型等方面就输电线路不平衡度计算的关键问题进行了研究。基于国内广泛使用的电力系统短路电流程序(power system department-short circuit current program,PSD-SCCP)提供的外网等值阻抗参数,建立了外网等值模型并给出求取等值参数的方法,由此得出更易理解且物理含义清晰的外网等值参数；根据以上等值模型,且输电线路采用精确的π型等值电路,计算输电线路不平衡度。通过与仿真结果的对比表明,所提出的不平衡度计算方法具有极高的准确性,且相关结论已在实际工程中应用。