分布式电源并网对配网馈线供电能力的影响分析

针对当前缺乏评估分布式电源DG接入对配电网馈线供电能力影响的有效手段的问题,提出一种基于分布式电源置信容量角度的评估方法。首先基于自回归移动平均ARMA模型和小时晴空指数分别建立了风光的随机出力模型,采用全年时序模型叠加随机正态分布模拟负荷。其次应用场景削减技术提高配电网可靠性计算效率,进而基于等可靠性原则提出了考虑网架故障的DG置信容量的求解流程,并从该角度提出了定量计算馈线供电能力增量的算法。最后结合IEEE-RBTS算例分析了馈线负荷、负荷曲线与DG出力相关性以及DG接入位置和容量对馈线供电能力的影响。结果表明选择DG接入负荷曲线与其出力相似度较高的馈线,以及优先规划DG以适当容量接入馈线末端有助于提升馈线的供电能力,延缓配网改造升级进程。

Analysis of Influences of Grid-connected Distributed Generation on Feeder Power Supply Ability in Distribution Network

At present,in light of the fact of lacking an effective method to assess the influences of distributed genera?tion(DG)on the feeder power supply ability(FPSA)after its access to distribution network(DN),an evaluation meth?od based on the credit capacity(CC)of DG is proposed.First,stochastic power models for wind farm and photovoltaic(PV)are established based on the auto-regression moving average(ARMA)model and hourly clearness index,respec?tively.Afterwards,load is simulated by the annual time series model,to which the stochastic normal distribution is add?ed.Then,the scenario reduction technique is applied to improve the efficiency when calculating the reliability of DN.In this way,a solving process for obtaining the DG’s CC,which takes the grid faults into account,is proposed based on the principle of equal reliability.In addition,a method for quantitively calculating the improvement in FPSA is pro?posed from this aspect.Finally,with the combination of an IEEE-RBTS system as an example,the influences of feeder load,the correlation between load curve and DG output,and the access location and capacity of DG on FPSA are ana?lyzed.Results show that connecting the DG to a feeder whose load curve is more similar to the DG output and arranging the DG of an appropriate capacity at the feeder terminal can improve FPSA,and delay the upgrading process of DN.