暂态电压失稳模式主导不稳定平衡点的计算

构建了负荷采用三阶感应电动机并联恒阻抗动态模型时电力系统暂态电压稳定分析的数学模型。针对采用牛顿法求取故障后系统电压失稳模式主导不稳定平衡点（CUEP）存在的初值确定难题，提出了一种实用的解决方案：通过判别给定故障的主导负荷母线，对主导负荷母线以外系统由故障后稳定平衡点处的状态进行戴维南等值，对负荷中感应电动机部分采用其稳态等值电路，再由感应电动机的转矩特性求得CUEP附近的一个点作为迭代初值，以计算CUEP；并且，还给出了如何得到更接近CUEP的迭代初值以更可靠求得CUEP的方法。IEEE 9节点系统和IEEE 39节点系统的计算结果验证了该方法的可靠有效。

Computation of Controlling Unstable Equilibrium Point Corresponding to Transient Voltage Instability Mode

The three order induction motor paralleled with const impedance model is used to represent load, and the mathematical model of analyzing the transient voltage stability of power system is built up. Aimed at the problem of choosing the initial point when the Newton method is used to compute the voltage instability mode controlling unstable equilibrium point (CUEP), a practical solving scheme is presented: by identifying the controlling load bus of the given fault, and using the Thevenin equivalent circuit to represent the rest of the system at the state of the post disturbance stable equilibrium point, using the steady equivalent circuit to represent the induction motor in composite load, and then using the torque characteristics of induction motor, a point near the CUEP is gained to be the initial point. Moreover, the method of getting the initial point that is more close to the CUEP and then finding the CUEP more reliably is also given. For the instances of IEEE 9-bus system and IEEE 39-bus system, the credibility and effectiveness of the method is validated.