基于无迹变换法的电力系统小扰动稳定概率分析

Probability Analysis of Small Disturbance Stability in Power System Based on Unscented Transformation Method

针对电力系统中关于负荷水平随机因素的不确定性,提出一种基于无迹变换法的电力系统小扰动稳定概率分析方法。该方法通过对称采样策略将概率分析问题转换为确定性分析问题,再根据无迹变换法中各个采样点权重的分配计算出小扰动稳定评估指标。基于MATLAB中电力系统分析软件包(power system analysis toolbox,PSAT)的3机9节点系统进行算例验证,并对10机39节点系统进行了小扰动稳定概率分析,通过无迹变换法和两点估计法的对比,验证了所提方法的有效性和实用性。仿真结果表明:无迹变换法与蒙特卡罗法、两点估计法计算结果的相对误差很小,但无迹变换法的时间远远小于蒙特卡罗法,能够实现小扰动稳定概率分析的快速评估,且满足工程应用的要求。

Aiming at the uncertainty of random factors of load level in the power system,a probability analysis method for small disturbance stability of the power system based on the unscented transformation method is proposed.The method transforms the prob⁃ability analysis problem into a deterministic analysis problem through a symmetric sampling strategy,and then calculates the prob⁃ability index of small disturbance stability according to the weight distribution of each sampling point by the unscented transformation method.The example analysis is verified based on the power system analysis toolbox(PSAT)3-machine 9-bus system in MATLAB.Then,the probability analysis of small disturbance stability for a 10-machine 39-bus system is performed.The validity and practicability of the proposed method are verified by comparing the unscented transformation method with the two-point estimation method.The simulation results show that the relative errors among the unscented transformation,Monte Carlo and two-point estima⁃tion methods are small,but the unscented transformation method takes much less time than the Monte Carlo method,which enables the rapid evaluation of small disturbance stability probability analysis and meets the requirements of engineering applications.