基于2m+1点估计法的考虑风力发电接入时电力系统谐波概率潮流算法

An Algorithm Based on 2m+1 Point Estimate Method for Harmonic Probabilistic Load Flow Calculation of Power Systems Incorporating Wind Power

谐波概率潮流是评估风电接入对电网运行影响的基础。针对具有间歇性和波动性的风力发电装置接入电网时注入的谐波电流幅值和相位具有不确定性的问题,提出了一种基于2m+1点估计法的谐波概率潮流分析方法。该方法避免建立已知随机变量和待求随机变量之间的解析关系式,也无需已知输入随机变量的概率密度分布,仅根据样本数据的高阶矩构造估计点,得到电网支路谐波电流的期望、方差等统计信息,进而求得电网各支路谐波电流的分布范围。基于实际电网算例对文中所述方法进行验证,结果表明在计算精度相仿的情况下该方法比蒙特卡洛法仿真计算量更少,并且比区间分析法所得的结果更科学、合理。此外,考虑谐波注入源谐波电流幅值和相位的双重不确定性分析所得结果更符合实际情况。

Probabilistic harmonic power flow（PHPF） is basis of evaluating impact of wind power integration on grid. A PHPF scheme based on 2m＋1 point estimate is proposed on account of uncertainties of injected harmonic current amplitudes and phases caused by intermittent and volatile new energy power generation device connected to electricity grid. This method eliminates establishment of analytic relationship between input and output random variables,dispenses withprobability density function of input random variables. According to higher moment of sample data for making up estimation point, expectation, variance and other statistical parameters of branches can be calculated. Actual example is adopted to validate theproposed method and results show that accuracy of this method is similar to that of the Monte Carlo simulation with less calculationtime. In comparison with interval analysis method, the proposed methodis more scientific and reasonable. Moreover, results considering double uncertainty amplitude and phase of harmonic injection source conform practical situation better.