Active Power Coordination Control Strategy For AC/DC Hybrid Systems Considering Wind Farm Regulation Capability

The vast area of China contains a large number of wind energy resources,and the establishment of large-scale wind power generation energy bases is an important way for my country to achieve "Carbon peak carbon neutralization".In recent years,with the rapid development of high-voltage direct current transmission systems,the transmission of power grid with the high-proportion wind power to the load center through the AC/DC hybrid system has become a mainstream form of power transmission.However,the grid connection of large-scale wind farms has profoundly changed the dynamic characteristics of traditional power system,increased the complexity of operation analysis of modern power system,and further affected the safe and stable operation of power systems with the high-proportion wind power.To better into the future of the power system planning,control and operational aspects of providing positive feasible solutions,based on the AC/DC hybrid system with the high-proportion wind power as the research object,the system model is built and the relevant coordination control strategy of AC/DC hybrid delivery system is studied,and the specific research work are as follows.In terms of model building,this paper established the model of AC/DC hybrid system with the high-proportion wind power on the electromagnetic transient simulation platform.In particular,in order to improve the operation efficiency of the model,this paper conducted in-depth research on wind farm equivalent modeling.First of all,according to the clustering equivalent index proposed in this paper,a wind farm clustering equivalent modeling method based on an improved clustering algorithm is proposed,which greatly improves the simulation efficiency of the wind farm model.Secondly,in order to overcome the problem of large operational data errors between the clustering equivalence model and the detailed model,a neural network-clustering hybrid equivalence modeling framework was designed by deep learning method,and the historical data of the model was collected to train the deep neural network to establish the error correction model between the clustering equivalence model and the detailed model.Finally,the proposed equivalence model is verified in different typical scenarios,and the results show that the proposed wind farm equivalence model not only retains the advantages of high simulation efficiency of cluster equivalence model,but also more accurately reflects the operation characteristics of detailed model.In terms of the active power coordination control strategy of the AC/DC hybrid system that mitigate the HVDC subsequent commutation failures,firstly,based on the established wind farm equivalence model,the power flow transfer trend of the system is analyzed,and it is proposed to reduce the active power transmission of the DC transmission system to reduce the reactive power demand of the inverter side,so as to mitigate the HVDC subsequent commutation failures.Secondlly,since the adjacent AC transmission line faces the risk of overload when the HVDC commutation failure occurs,a power judgment method for the sending-end power grid with the high-proportion of wind power is proposed.The power control mode adjusts the power output of the sending end grid,fully taps the potential of the wind farm to participate in the grid regulation,and realizes the active power coordination control of the AC/DC hybrid systems considering the wind farm regulation capability.Finally,the proposed control strategy has been simulated and verified in the electromagnetic transient simulation platform and the actual power grid simulation system.The simulation results show that the strategy not only fully exerts the control potential of the wind farm in the sending grid with high-proportion wind power,but also compared with the traditional control method,this strategy can greatly save the economic cost of power grid regulation at the sending end.