对计算静态电压稳定裕度的连续潮流法和最优潮流法进行比较和分析.针对两种方法求得的静态电压稳定裕度存在差异性的问题,在定义两种方法识别电压稳定临界点类型的等价性基础上,指出它们之间存在差异的原因在于描述潮流的方程不一致.在计算稳定裕度的最优潮流新模型中,引入描述发电机无功出力与其机端电压的互补约束条件,并采用与连续潮流法相同的发电机有功增长方向.分别对IEEE9节点、IEEE39节点和某省级748节点系统进行静态电压稳定裕度计算,结果表明由新的最优潮流模型获得的稳定裕度和分岔点类型均与由连续潮流模型获得的一致.
This paper deals with two methods for computing the stability margin of static voltage, namely the optimal power flow method and the continuation power flow method. In the investigation, first, based on the equivalency definition of the two methods for determining the critical points of voltage stability, the cause of the stability margin difference between the two methods, namely, the ineonformity of power flow equations, is pointed out. Then, the complementarity constraints describing the reactive power and the terminal voltage of generators are introduced in a new optimal power flow model, and the increase direction of the active power outputs of generators, which is the same as that of the continuation power flow model, is adopted. Computational results on the IEEE 9-bus system, the IEEE 39-bus system and a real provincial 748-bus power system illustrate that the stability margin of the static voltage and the bifurcation type obtained by the optimal power flow model accord well with those obtained by the continuation power flow model.