三相不平衡配网多目标优化迭代求解方法

A multi-objective iterative optimization method for three-phase unbalanced distribution net-works

针对分布式可再生能源三相不平衡接入配网后的影响,文章提出了一种三相不平衡配网多目标优化迭代求解方法。基于柔性多状态开关调控手段,考虑三相线路间的耦合关系,建立了半正定多目标优化模型,以柔性多状态开关各端口三相有功和无功功率指令为优化变量,对系统网损和三相不平衡度进行综合治理。针对当三项不平衡度在优化目标中权重较大时,半正定优化模型秩1约束松弛不精确的问题,提出了一种基于支路电流矩阵主对角元不等式约束的迭代求解方法,能以较小的计算负担显著减小的半正定松弛间隙,进而提高最优潮流计算结果的准确性与调度指令的可靠性。

To alleviate the impact of output uncertainty of renewable energy sources(RESs)in unbalanced distribution networks,this paper proposed a multi-objective iterative optimization method for three-phase unbalanced distribution networks.Based on the soft open point(SOP)control techniques,a semidefinite programming(SDP)optimization model is established considering the coupling relationship between three phases.The active and reactive power operation points of the SOP were optimized to minimize system loss and mitigate three-phase unbalance together.To efficiently solve the proposed model,an iterative solving method based on the inequality constraints of the principal diagonal elements of the branch current matrix is proposed to strengthen the exactness of the SDP rank-one relaxation.Case studies show that the proposed method can fully utilize the flexible power flow regulation ability of the multi-terminal SOP to reduce system loss and mitigate three-phase unbalance.The proposed iterative solving method can improve the accuracy of the optimization results.