四种潮流计算的近似等值方法及其适用性分析

针对目前采用已有的网络静态等值方法在电网潮流计算不收敛时无法对网络进行等值化简的问题,提出了四种可在潮流结果未知的条件下对网络进行近似等值的方法,给出了每种等值方法的等值模型及计算过程,并通过算例对四种近似等值方法进行了比较分析,进一步探讨了在电网不同负荷水平下各近似等值方法的适应性。结果表明,四种方法均能满足近似等值的精度要求,其中保留PV节点的节点功率转阻抗近似等值法在轻负荷和重负荷条件下均有较好的等值精度,外网近似等值对边界节点的潮流计算结果精度影响最大。

Analysis of Four Approximate Equivalents Methods for Power Flow Calculation and Its Applicablity

In order to solve the problem that it is failed to get the equivalent of network when power flow calculation is not convergent, this article puts forward four approximate equivalent methods without knowing the accurate results of power flow. The equivalent module and calculation progress of each method are given. And then four methods are compared with the examples. Moreover, the adaptability of each equivalent method is discussed under different operation conditions. The results indicate that four methods can satisfy the precision requirements of approximate equivalent, among which the method that transfers node power to impedance with preserving PV nodes has better equivalent precision both under the light and heavy load conditions. The power flow results of boundary nodes are most affected by the equivalent of network.