计及感应电动机负荷的电力系统在线电压稳定指标

在任意时间断面上可以从某一负荷母线向系统看进去，将整个系统等值为一个电压源经输电线路向所研究的负荷母线供电的两节点系统，在此基础上计及动态感应电动机负荷，提出了负荷母线在线小干扰电压稳定指标。利用实时等值得到的系统等值电势和阻抗，经过简单的计算，可以得到被监测负荷母线的电压稳定指标。将系统中所有负荷母线的最小指标值作为该系统的电压稳定指标，该最小值所对应的母线为系统中的最薄弱母线。系统电压稳定指标与临界值0之间的距离反映了系统的电压稳定裕度。EPRI-36系统的数值仿真结果验证了该指标的有效性和准确性。所提出的指标克服了以往在线应用中基于潮流模型指标的不准确性问题，计算量小，适合于电力系统在线电压稳定分析与监测。

An On-line Voltage Stability Index of Power System Considering Induction Motor Loads

For some load bus, the whole power system can be equivalent to a two bus system with source voltage supplying a load though a transmission line, as seem from the load bus at any time. An on-line voltage stability index has been presented considering induction motor loads based on the equivalent simple system. The on-line small disturbance voltage stability index can be easily calculated using the voltage phasor of equivalent source voltage and impedance from real time equivalence. The minimum value of all load bus index values can be looked as the voltage stability index of the whole power system. Correspondingly, the load bus with minimum value of the index is the weakest load bus. The distance between the index value and the critical value of 0 indicates the margin of voltage stability. The results of EPRI-36 system show that the validity and accuracy of the index. The voltage stability index avoids the inaccuracy of load flow model based indices and can be used to real time monitoring of power system voltage stability.