考虑不确定性的三相不平衡配网DG选址定容研究

可再生能源的分布式发电(Distributed Generation,DG)因其良好的环境效益受到关注,但分布式风力发电和光伏发电出力具有波动性和不确定性,这类分布式电源配置在网络中的节点位置和容量对于网络优化运行至关重要。由于配网中三相负荷经常不平衡,并且不同相之间的互阻抗也不平衡,这给分布式电源在配网中的选址定容带来了难度。考虑到三相不平衡潮流的影响,利用速度高、精度好为特点的考虑负荷模型和负荷接入类型的线性三相不平衡潮流法进行潮流计算。针对出力不确定的分布式电源在三相不平衡配网中的选址定容展开研究,建立了以减小网损、降低电压不平衡度、防止电压跌落的分布式电源多目标选址定容模型。针对分布式电源选址定容后的运行维护情况,提出了成本效益分析,来考虑中长期选址定容的合理性。为了求解文中的多目标模型,提出了改进磷虾群搜索算法,保留最优个体,提高收敛速度。利用IEEE37节点系统进行算例验证,分析了网损、电压不平衡度、每相电压在分布式电源接入后的情况。

Distributed Generations Optimal Locationing and Sizing in Unbalanced three Phase Distribution Systems considering the Uncertainties

The renewable energy based distributed generation(DG)draws much attention because of its environmental-friendly feature.Meanwhile,this kind of distributed generation and PV generation is volatile and uncertain.So it’s important to make good placement in the distribution network to make full use of the profit.But it must be noted that distribution networks due to the unequal three-phase loads and mutual impedance between various phases of lines are virtually unbalanced.So in this paper,determination of the appropriate size and place of distributed generations is done in unbalanced distribution network that the appropriate size distributed generations obtained with respect to probabilistic methods and their convenient location is selected using weighted multi-objective method.With regard to the impact of exact load flow in calculations,linear three-phase unbalanced load flow method considering the loads model and loads connection type is used which is the fast and accurate unbalanced load flow method.To solve this multi-objective model,an improved krill herd algorithm is proposed,which can bring a rapid convergence.Simulations are done in IEEE 37 bus unbalanced network in Matlab software.The simulation results indicate that network power losses and voltage unbalance factor are reduced,voltage profile of each phase is improved and significant profit is obtained for distribution companies.