含分布式电源配电网供电能力的概率评估

Probabilistic Evaluation on Power Supply Capability of Distribution System with Distributed Generations

随着分布式电源渗透率的不断提高,配电网对供电能力评估变得更加困难。本文考虑到分布式电源出力的随机性,构建了配电网对供电能力的评估指标,利用两点估计方法的特点将研究对象的随机性转化为确定性并进行计算,然后利用重复潮流法计算出供电功率样本值,通过柯尼斯-费希尔级数计算供电功率概率分布函数并建立概率密度模型,提出了含分布式电源的配电网供电能力的概率评估方法。通过IEEE33节点算例与蒙特卡罗方法对比分析,该方法在可行性和快速性方面具有优势,可以有效评估含分布式电源配电网的供电能力。

The increasing penetration of distributed generations(DGs)makes the evaluation on the power supply capability of distribution network more complicated. With the consideration of output uncertainties of DGs,the evaluation indexes for the power supply capability of distribution network are proposed. By using the two-point estimate method, the randomness of the research object can be changed into a deterministic problem,then the repeat power flow(RPF) algorithm is used to calculate the supply power of samples. According to Cornish-Fisher expansion,the probabilistic distribution functions of supply power are calculated,and a model of probability density is established. Afterwards,a probabilistic evaluation method for the power supply capability of distribution network with DGs is proposed. Based on a numerical example of an IEEE 33-bus system,the proposed method is compared with Monte Carlo simulation;the analysis results show that the proposed method has advantages in feasibility and rapidness,which can effectively evaluate the power supply capability of distribution network with DGs.