含分布式电源的城市电网故障分析方法研究

Ｒesearch on Failure Analysis Method of Urban Power Grid with Distributed Generation

摘要:

分布式电源大规模接入城市电网会给城市电网的故障特征带来一定的影响,其出力的随机性会引起故障特征的不确定。针对现有故障分析方法未考虑出力随机性的影响,提出一种基于蒙特卡洛法的含分布式电源的城市电网故障分析方法。首先,基于分布式电源出力的概率模型,利用蒙特卡洛法进行随机抽样;然后,通过PQ控制和低电压穿越策略下的故障模型进行计算,形成故障电压、短路电流的概率分布;最后,通过算例进行仿真分析。结果表明,分布式电源接入城市电网后故障特征具有概率特性,该方法计及分布式电源出力随机性的影响,可得故障电压、短路电流的概率分布,可对城市电网故障特性分析以及整定值的选取提供依据。

Abstract:

Large － scale access of distributed generation to urban power grid will have certain impact on the fault characteristics of urban power grid，and the randomness of its output will cause uncertainty of the fault characteristics． Aiming at the fact that the existing random analysis methods do not consider the influence of output randomness，a failure analysis method for urban power grid with distributed generation based on Monte Carlo method is proposed． Based on the probabilistic model of distributed generation output，Monte Carlo method is used for random sampling，and then the fault model under PQ control and low － voltage ride － through strategy is used to calculate the probability distribution of fault voltage and short － circuit current． Finally，it is verified with a calculation example． The results show that the fault characteristics of distributed generation connected to urban power grid have probabilistic characteristics． The proposed method can obtain the probability distribution of fault voltage and short － circuit current，and can provide a basis for the analysis of fault characteristics of urban power grid and the selection of setting values