中文摘要：

电压失稳概率受确定因素和不确定因素2方面的影响，针对这一问题，提出基于戴维南等值参数的电力系统电压失稳概率计算方法．选定负荷阻抗模与戴维南阻抗模的比值作为失稳判定指标，在不考虑不确定事故因素的影响下，推导出基于戴维南等值参数的电压失稳概率分布函数的解析表达式．考虑到不确定性事故的影响，最终得到系统电压失稳概率的计算方法．IEEE RTS＇79算例上的仿真计算验证了该方法的可行性与有效性，同时表明该方法能够客观地反映系统发生电压失稳的可能性．

英文摘要：

The probability of voltage instability is dependent upon both definite factors and indefinite factors. To deal with this phenomenon, a new method to determine the voltage instability probability of the power system based on Thevenin equivalent parameters is proposed. The ratio of load impedance module to Thevenin impedance module is selected as the voltage instability index. Then an expression of probability distribution function for voltage instability was developed based on Thevenin equivalent parameters regardless of any indefinite factor. Finally, a more complete method of voltage instability probability calculation was obtained with the inclusion of the uncertain factors. Simulations on IEEE RTS＇79 proved the method is feasible and effective, and indicated that this method can accurately predict the probability of voltage instability occurring in a power system at a given time.