基于扩展Nataf变换的交直流混合系统概率潮流计算方法

随着新型电力系统高比例新能源与高比例电力电子化的“双高”特征日益凸显,交直流混合已成为中国电力系统的典型特征。伴随着可再生能源出力的随机性,交直流混合系统的潮流也表现出随机性。为此,提出一种基于扩展Nataf变换和拉丁超立方采样的交直流混合系统概率潮流计算方法。首先,建立适用于概率潮流计算的交直流混合系统潮流模型。同时,针对Nataf变换无法处理源荷相关系数矩阵非正定的情况,采用一种基于奇异值分解的扩展Nataf变换,并结合拉丁超立方采样进行交直流混合系统的概率潮流计算。此外,针对传统Gram-charlier级数存在节点电压幅值等状态变量概率为负值的情况,提出一种C型Gram-charlier级数以解决该问题。最后,在改进的57节点交直流混合系统中验证了所提方法的有效性。

Probabilistic Power Flow Calculation Method of AC/DC Hybrid System Based on Extended Nataf Transformation

Along with the "double high" characteristic of high proportion new energy and high proportion electric power electronic in new power system, AC/DC hybrid has become a typical characteristic of Chinese power system. Along with the randomness of renewable energy output, the power flow of AC/DC hybrid system also shows randomness.Therefore, a probabilistic power flow calculation method for AC-DC hybrid system based on extended Nataf transformation and Latin Hypercube sampling is proposed in this paper. Firstly, a power flow model of AC/DC hybrid system is established for probabilistic power flow calculation. At the same time, in the case that the Nataf transform cannot deal with the non-positive definite correlation coefficient matrix, an extended Nataf transformation based on singular value decomposition and Latin hypercube sampling are adopted in this paper to calculate the probabilistic power flow of AC-DC hybrid system.In addition, a C-type Gram-charlier series is proposed to solve the problem that the probability of state variables such as node voltage amplitude may be negative in the traditional Gram-charlier series. Finally, the effectiveness of the proposed method is verified in an improved 57-node AC/DC hybrid system.