适应于可再生能源接入下配电网极限线损的计算方法

Calculation method of limit line loss of renewable energy distribution network

随着可再生能源的开发与利用大幅提升,分布式的电源接入给中压配电网潮流分布带来了波动性和不确定性,从而加大了线损计算的难度,不利于电网经济性考核指标的制定.因此,极限线损的计算方法与模型越来越引起重视.提出了一种基于半不变量的配电网极限线损计算模型,以实现含可再生能源配电网极限线损的快速计算.首先,分别依据潮流计算与统计数据进行计算,得到配电网各节点与电源的各阶半不变量;然后,用Gram-Charlier(GC)级数展开式计算得到各个状态变量的分布函数与概率密度函数;最后,根据置信区间确定配电网极限线损.以IEEE34节点系统为算例,分析了不同节点分布式电源接入对配电网的影响,验证了应用半不变量法的线损计算模型的计算精度及其在大规模配电网应用中的计算速度优势.

With the advancement of renewable energy technology and increasing demand,the access of distributed generations introduces volatility and uncertainty to the power flow distribution within medium voltage distribution networks.Consequently,the volatile and uncertain nature significantly hinders the accurate line loss calculation and establishment of grid assessment indicators.This study proposes a semi-invariant calculation model that aids realize an efficient calculation approach for limit line loss of the distribution network containing renewable energy.Initially,according to the power flow calculation and statistical data,the semi-invariants of each node and generations in the distribution network are calculated.Next,the distribution function and probability density function of each state index are calculated with the Gram-Charlier(GC)series expansion formula.Finally,the limit line loss of the distribution network is determined according to the confidence interval.IEEE34 node system is chosen as an example in this study to analyse the influence of different node distributed power access on distribution network.The calculation accuracy of line loss calculation model based on semi-invariant method and its calculation speed advantage in large-scale distribution network application is verified.