Research On Multi-Object Coordination And Optimization Automatic Control Algorithm For AC/DC Power Grid

At present,China's energy-rich regions are mainly concentrated in the northwest,southwest,and northeast regions,showing a trend of more in the West and less in the East,while the load centers are located in the east and south.Large-scale renewable energy cannot be absorbed locally,so it needs to be transported to the load center through the AC/DC hybrid network over a long distance.UHVDC transmission has the advantages of long transmission distance,small loss,and large capacity,which will certainly be the development trend of China's power grid in the future.Nowadays,there are more and more decision-making systems and control systems in AC/DC hybrid systems,but they are all self-contained with are problems such as information islands and control isolation.However,the behavior of control system on the power grid affects each other.Mutual coordination can only be achieved manually by the dispatcher at this stage.Because of the various constraints that need to be considered for manual coordinated control,the efficiency is low,and errors are prone to affect the safety of the power grid.As the power grid becomes more and more complex,this contradiction becomes more prominent.At the same time,there are complex logics in each control system.Manually coordinating the various systems for control not only has hidden safety hazards,but also it is difficult to achieve the optimal,and it cannot take advantage of the rapid response of the automatic control system.This paper fully considers the existing control methods and condenses two typical application scenarios for AC/DC hybrid system coordinated control,which are respectively application scenarios for energy-saving optimization and safety and stability.First,the data interface of the power grid is researched,and the calling relationship between the optimization algorithm and each control subsystem is clearly defined.Then,the physical model of the high-voltage direct current(HVDC)is modeled online to implement the conversion of its mathematical model in order to facilitate On this basis,mathematical calculations are performed.Next,establish the optimal power flow(Optimal Power Flow,OPF)model in two typical scenarios:(1)Establish an economical and energy-saving optimization model for the optimal power allocation of channels in the power grid;(2)Establish an orientation for the correction control of important sections Safe and stable optimized model.The model is solved using step-control interior point method in MATPOWER,which is realized by coordinating the Automatic Generation Control(AGC),Automatic Voltage Control(AVC)and Automatic Direct Current(ADC)These two typical scenes.The model verification first uses offline format(BPA format)for data verification,secondly uses online format(E format)for data verification,and finally uses online continuous open-loop operation to verify the comprehensive effect of the model,thereby ensuring that the AC / DC hybrid system On the existing basis,significantly improve the economy and safety.At the same time,in view of the current environment of power market reform,energy-saving optimization for economic dispatch can effectively reduce network losses,reduce variable costs in transmission costs,thereby reducing node marginal electricity prices,and can promote power marketization reform from the transmission end.Finally,an AC/DC hybrid system model based on convex approximation is proposed.Some constraints are transformed into a second-order cone by convex approximation,and a traditional non-convex power flow model is transformed into a convex second-order cone model.By solving this convex problem,The optimal solution is obtained,under the premise of ensuring the calculation accuracy,the calculation efficiency is improved.