Research On AGC Strategy Of Power System Considering Wind Power Output Uncertainty

Automatic Generation Control(AGC),as an important means of secondary frequency modulation in power systems,has always been valued by various parties.With the continuous expansion of the development scale of the new energy industry and the increasing penetration of wind power,the adverse effects of the intermittent and random characteristics of wind energy on the frequency control of the power grid have attracted widespread attention.Engineering test data and related research show that the higher the proportion of wind power to the system capacity,the more obvious the impact on the frequency characteristics of the power system.Based on the influence of wind power output changes on AGC system parameters,this paper proposes a compensated model predictive control(MPC)strategy to cope with the negative impact of wind power output uncertainty on traditional AGC.The details are as follows:1)Based on the basic principles of AGC frequency modulation,the construction mechanism of the transfer function model and simulation model of each unit of AGC is elaborated to form the AGC model of the regional interconnected power system;the characteristics of power exchange between regions,basic control methods and constraints in the system are described.2)Considering the decisive effect of AGC parameters on the control performance of the system,we focus on the influence of the unit power adjustment and the inertial time constant of the power system on the system control performance index.Define the dynamic wind power penetration as the ratio of the real-time output power of wind power to the system capacity,analyze the mechanism of its influence on the unit power and inertial time constant of the power system,and then obtain the correspondence between the change of dynamic wind power penetration and the performance of AGC relationship.3)Using MPC as the basic control strategy,it is applied to the AGC model of wind power systems.From the aspects of predictive model,rolling optimization and feedback correction,the basic principles and control mechanism of MPC are expounded,and the two-region power system AGC is built through Matlab / Simulik The model and simulation verify the effectiveness of MPC as a controller for automatic generation control.4)On the basis of MPC,combined with the influence of the uncertainty of wind power output on the parameter setting of the AGC system,a compensation MPC control strategy is proposed to construct a series structure of traditional MPC and compensation links.The frequency characteristics of the system are optimized with Particle Swarm Optimization(PSO).The design of the dynamic adjustment mechanism of the compensation link parameters with the change of dynamic wind power penetration enables the controller to adapt to the uncertain changes in wind power output.5)Simulation and verification are carried out in Matlab / Simulik environment.The feasibility and effectiveness of the proposed method for system frequency control are simulated when the dynamic wind power penetration changes due to the simulation of wind turbine chain failure,wind turbine and conventional unit entry and withdrawal,etc.