低压配电网三相不平衡负载参数的辨识方法研究

为了解决现阶段计算低压配电网负荷上实际压降、三相负荷不平衡度时忽略三相负荷不平衡与中性线阻抗同时存在的实际情况所引起的求解结果不准确问题,提出一种实时计算负荷实际大小及负荷侧虚拟中性点电压的方法,以此辅助监测低压配电网安全。首先建立与低压配电网等值阻抗网络匹配的高阶微分方程模型,再利用方程系数与等值阻抗参数之间的关系,采用暂态数据辨识模型参数,实时求取三相负荷等值阻抗,中性线阻抗及虚拟中性点电压。仿真结果验证了该方法的有效性和准确性。

Three-phase unbalanced load parameters identification of low voltage power utilization network

In order to solve the inaccuracy problem in calculating the actual voltage drop and the degree of three-phase load unbalanced of low voltage electrical load when takes no consideration of three-phase unbalanced load and non-ignorable neutral line impedance, a new safety monitoring method is presented by real-time monitoring of real voltage drop across the load. The new method establishes a high order equation model matching the equivalent impedance gird of real load of low voltage distribution network, based on the relationship between equation parameters and equivalent impendance parameters, uses transient signal to identify the model parameters, and calculates load fluctuations in real-time, neutral line impedance and load virtual point voltage. Simulation results demonstrate the effectiveness and accuracy of the proposed method.