基于戴维南等值的配电网合环冲击电流计算

Study on Surge Current Due to Closing Loop in Distribution Network Based on Thevenin's Equivalent

针对合环操作冲击电流可能越限的问题,提出一种基于戴维南等值的冲击电流计算方法。该方法以戴维南定理为基础建立数学模型,采用网络潮流计算求得其中的等值电势,采用节点阻抗矩阵求得其中等值阻抗,继而推导出冲击电流和稳态环流的对应关系,并利用电流分布系数法研究合环支路冲击电流对其它支路的影响。针对配电网没有馈线负荷量测的问题,将馈线负荷分别集中于两侧馈线的首末相异端,由潮流计算直接获取馈线合环稳态电流最大值,并进一步求得冲击电流的最大值。通过实际算例仿真,验证了所述方法的正确性和有效性,对实际配电网的调度运行具有一定的指导意义。

The mathematical model of closing loop operation is established and a method for surge current calculation based on Thevenin＇s equivalent is proposed in this paper. The equivalent electric potential and impedance are calculated accurately through network power flow calculation and node impedance matrix, and the relationship between surge current and stable loop current is gained. Further more, the impact of surge current on other branches is studied using current distribution coefficient. Because there is no power measurement on feeder lines, in this paper, the feeder loads are centralized on the different begin or end of the corresponding feeders, then the max stable current and surge current can be gained by power flow calculation. Actual examples and simulation results verify the correctness and validity of the proposed method, which can provide effective decision--making supporting information for dispatchers.