电力系统暂态稳定概率

在电力系统概率安全性评估中,预想事故下系统暂态失稳概率的计算是一个基本环节.文中基于安全域的研究成果,提出了一个离散和连续相结合的暂态失稳概率模型.其中除计及了节点注入功率不确定性、沿线事故发生地点的不确定性以及事故清除时间的不确定性外,还计及了负荷模型的不确定性.同时,采用以半不变量为基础的Gram-Charlier级数法计算截断正态分布随机变量的联合概率分布,使概率分布的考虑更加符合实际.算例表明该方法具有较高的计算效率.

Transient Stability Probability of Power System

To calculate the probability of system transient instability is a basic step in the probabilistic assessment of power system security. Based on the outcomes of study on the dynamic security region (DSR), a transient instability probability model combining discrete and continuous stochastic variables is proposed. In addition to considering the uncertainties of load forecasting at each node, the fault occurrence location and the fault-clearing time, the uncertainty of load model is also taken into account. Furthermore, the method of Gram-Charlier progression based on the cumulants is adopted to calculate the joint probabilistic distribution of truncated normal distribution, which is closer to real case. Arithmetic examples demonstrate the high calculation efficiency of the approach proposed.