含相关性随机变量的概率潮流三点估计法

摘要

采用三阶多项式正态变换方法,将非正态相关的多维随机变量变换到正态不相关的变量空间,在正态不相关的变量空间中取采样点,最后将这些采样点通过逆变换重新变换到非正态相关的变量空间中进行潮流计算。这种变换—逆变换的过程使得点估计方法能够处理含非正态相关随机变量的概率潮流问题。利用该技术,提出了一种求解包含风力发电和负荷随机性的概率潮流问题的三点估计法。基于IEEE 118节点系统的算例分析表明,该方法具有较高的精度,且计算效率高,为讨论基于相关性的概率潮流问题提供了一种有效的工具。%The third-order polynomial normal transformation （TPNT） technique was employed to transform a multivariate non-normal dependent random variables group into a multivariate standard normal independent one. Sampling points were obtained in the standard normal independent variable space and transformed into multivariate non-normal dependent ones. Incorporating three-point estimate method with TPNT technique, a TPNT-based three-point estimate method is proposed to solve probabilistic power flow problems with non-normal dependent variables. A case study on a slightly modified IEEE 118-bus system shows that, the proposed method has high accuracy and computational efficiency. It is a qualified tool to discuss the probabilistic power flow problems with non-normal dependent variables.