Coordinated Optimization And Control Of Distributed Network With Flexible Multi-state Switches

Due to the increasing number of DG,stored energy and controllable load attached to the distribution network,it's hard for the traditional regulation method to meet the needs of security,stability and flexibility.Under this background,flexible multi-state switch(FMSS)is derived.Taken the functional characteristics of FMSS into consideration,there will be a long time for several FMSSs and conventional switches coexist.As a result,investigation is required for the coordinated optimization control technology,which improves the coordination between several FMSSs,and the coordination between FMSS and conventional regulation method.Based on three time scales,the partitioning method,multi-objective stochastic operation method and distributed adaptive control method are proposed in this paper.They comprise the overall framework of the distribution network with FMSS.Major outcomes of this research work include:(1)A partitioning method for distribution network with FMSS is proposed.Targeted at the circumstances that several areas with different voltage level of the distribution network are flexibly connected by FMSS,the partitioning method is given based on the theoretical framework of the multi-level graph partitioning.The proposed partitioning method can not only optimize the operation index,but also coordinate with the regulation of FMSS,which further improve the operation state of the distribution network.(2)A multi-objective stochastic operation optimization for distribution network with FMSS is studied.Firstly,multi-objective stochastic operation optimization model of the distribution network with FMSS is proposed.In the model,the influence of the new energy sources is taken into consideration.Optimization variables of the model are the power of FMSS,the action time and on-off state of the conventional switches.And the model contains two sub-problems,network reconfiguration and FMSS regulation.Secondly,the operation method is obtained by the hybrid optimization algorithm.In the case study,the feasibility and the validity of the method are proved.(3)A distributed adaptive control for distribution network with FMSS is provided.First of all,the overall framework of the distribution network with FMSS is introduced.Based on the improved discrete consensus algorithm with constraint and model free adaptive control theory,control strategies for the feeder load index and voltage are presented.In the case study,the validity of the control strategy is proved.Furthermore,its effect is compared and its applicability is analyzed.