Transient Stability Analysis Of New Energy Source Power Grid And Control Strategy Research

With the increase of wind energy penetration,a large number of power electronic equipment are connected to the power grid,and the new energy gridconnected power generation system represented by direct drive fans presents a completely different response behavior from the conventional power generation system,which makes the transient characteristics of the power system qualitatively changed,and the lack of inertia of the power system may cause the transient stability of the system.In order to improve the transient stability of the system,the main contents and results of this paper are as follows:Aiming at the characteristics of multiple control links and multiple time scales coupling of direct drive fan grid-connected power generation systems,and it is difficult to analyze the transient stability of such systems,this paper proposes a research method for transient energy transfer paths.Firstly,this paper reasonably lowers the order of the fan delivery system,divides the fan delivery system into multiple subsystems according to the different physical links and control links in the order reduction system,and constructs the transient energy model of each subsystem by the first integration method.Secondly,the transient components corresponding to each subsystem of the wind turbine downgrading system are obtained by establishing differential equations,and the transient interaction energy corresponding to the subsystem is determined based on the corresponding transient components of each subsystem,and finally,the transient interaction energy corresponding to each subsystem is analyzed,the transient energy transfer path between each subsystem in the wind turbine delivery system is described,and the transient energy convergence link is determined,which provides a theoretical basis for the control strategy of the wind farm.In view of the fact that most of the existing literature does not consider the interaction between wind turbines and wind turbines and between fans and power grids,this paper constructs a transient energy model of direct drive wind farms based on the analysis of the stand-alone model of direct drive fans,considers the interaction between each fan in the wind farm and between the wind turbine and the power grid,and divides the transient energy model of the direct drive wind farm into three parts:the transient energy induced by the fan itself,the coupled transient energy between the machine and the grid.and derive the specific expressions corresponding to the transient energies of these three parts in detail;On this basis,the Lyapunov second method is used to analyze the variation law of transient energy in these three parts,and the influence of wind turbine access distance,voltage drop amplitude and phaselocked loop control parameters on the transient stability of the system is explored.In view of the problem that the existing research does not fully consider the collaborative control ability between the wind turbine and the wind turbine in the direct drive wind farm,this paper quantitatively analyzes the stored energy corresponding to each subsystem in the wind farm,derives the specific expression of the stored energy corresponding to each subsystem,and determines the stability of each subsystem based on the Lyapunov second method,and analyzes the influence of control parameters on the stored energy.On this basis,combined with the transient energy induced by the wind turbine itself,the coupling transient energy between machines and the coupling transient energy of the machine network in the wind farm,the total stored energy of the wind farm is the goal,the corresponding constraints are formulated according to the influence law of parameters,and a collaborative optimization model with multiple constraints and multiple parameters is established to optimize the wind farm globally,and finally achieve the purpose of improving the transient stability of the wind farm.