Research On Dynamic Characteristics Optimization Control Of Smart Distribution Network

With the increasing penetration of distributed generators,flexible loads,electric vehicles and energy storage devices in the power grid,the structure of distribution network has become diversified.It is no longer confined to the traditional power supply and distribution,but to form a modern energy network that can not only provide comprehensive energy,but also provide a variety of interactive services.But with the adverse dynamic problems such as voltage fluctuation,harmonic pollution and power flow instability,the dynamic process of distribution network becomes extremely complex,which brings unprecedented challenges to the safe,stable and economic operation of distribution network.Based on this background,this paper focuses on the technical methods of optimizing the dynamic characteristics of intelligent distribution network,and proposes the energy compensation method and the dynamic characteristics optimization control method based on closed loop.The details are as follows:Firstly,taking wind power system,photovoltaic system and electric vehicle system as the research objects,this paper analyses their respective mathematical models,grid-connected mode and control strategy.On this basis,a smart distribution grid model including wind power generation system and photovoltaic power generation system is constructed,and the possible adverse dynamics problem are analyzed.Secondly,aiming at the bad dynamic problem of intelligent distribution network,an energy compensation method is proposed,and an energy dynamic compensation device is designed based on this method.The device consists of VSC,DC/DC converter and supercapacitor.Supercapacitors can send energy to the power grid through DC/DC converters and VSC.Similarly,the power grid can send energy back to the supercapacitor bank through VSC and DC/DC converters for storage.Supercapacitor is used to suppress the fluctuation of voltage and power of the system by its fast charging and discharging characteristics.At the same time,the mathematical model and control strategy of the device are analyzed in detail,and the parameters of each part are designed.The improvement function of the device to the dynamic characteristics of the system is verified by simulation.Finally,based on the improvement of the energy dynamic compensation device,a dynamic characteristic optimization control method based on active connection is proposed and an active connection device is designed.The device adopts three-layer control architecture,namely,state identification layer,system control layer and signal output layer.This paper describes the mathematical model and control strategy of the active contact device,and focuses on the analysis of the control strategy of the active contact device working in the closed-loop state.The correctness and effectiveness of the device for optimal control of distribution network dynamic characteristics are verified by simulation.