考虑变量相关性的配电网电压稳定性分析

Voltage Stability Analysis of Distribution Network Considering Variable Correlation

接入配电网的分布式光伏发电出力具有强随机性和弱可控性,其与随机负荷共同作用导致配电网潮流呈现不确定性。为了在潮流计算中模拟光伏发电和光敏负荷之间的相关性,运用Copula函数建立两者的联合概率分布模型。通过拉丁超立方采样获取具有一定相关性的时序样本对,并代入配电网潮流方程计算潮流的联合概率分布。通过对IEEE33配电系统的仿真表明,考虑随机变量相关性的概率潮流结果更符合实际,更有助于分析节点电压的概率稳定性。

The distributed photovoltaic generation system connected to distribution network has strong randomness and weak controllability,which combined with random loads will cause the uncertainty of the power flow in distribution network.For simulating the correlation between photovoltaic generation and photosensitive load in the calculation of probabilistic power flow,the joint probability distribution model about the two random variables is established on base of Copula function.The time-ordered samples with certain correlation are obtained by Latin hypercube sampling technology firstly,and then are substituted into equations of power flow to calculate joint probability distribution of power flow.The simulation results of IEEE33 distribution system show that the probabilistic power flow considering the correlations of random variables are more in line with the actual,and are more helpful to analyze the probabilistic stability of node voltage.