Research On Digital-physical Hybrid Simulation Technology For Grid-connected Wind Farm

In order to achieve China’s goals of carbon reduction,energy carbon reduction and dual carbon reduction,expanding the proportion of non-fossil energy consumption represented by wind power and building a new power system with new energy as the main body have become the only way.Wind power generation is greatly affected by weather,region and other factors,and has the characteristics of intermittent,cyclical and fluctuating.After the wind farm is connected to the grid for power generation,higher requirements are put forward for the economic operation,stability control and distribution network operation of the power grid.In reality,the wind power system is poor in economy and bulky,and it is very inconvenient to directly use it as a research target.In order to have a deeper understanding of the operation mechanism of wind farms connected to the grid,it is necessary to find appropriate and effective simulation methods.Digital physical hybrid simulation combines the advantages of pure digital simulation and pure physical simulation to open up a new path for simulation development.The simulation method can not only save cost but also show the operating characteristics of the system well,which is an effective means to study the grid connection of wind turbines.This paper introduces the research status and related classification of wind turbines,and reviews the research status of digital-physical hybrid simulation.The structure of doubly-fed wind turbine power generation system was studied in depth,the mathematical model of wind turbine was established,and the principle,efficiency and output characteristics of wind energy conversion were studied in detail.The mathematical model of doubly-fed generator under different coordinate systems is established.On this basis,the control strategies of rotor-side converter and mesh-side converter are studied.The principle of digital physical hybrid simulation system is analyzed in detail,and five commonly used interface algorithms are summarized.Then,the principles,applicable scenarios and stability conditions of these five interface algorithms are derived and explained in detail.By comparing the ITM algorithm as the hybrid simulation interface algorithm,the stability of the algorithm is improved.The simulation model of wind farm grid connection was constructed,and the model was segmented by improved ITM interface algorithm.The simulation results verify the effectiveness of the segmentation method.On this basis,the converter is used instead of the grid-side controlled source to simulate the digital-physical hybrid simulation experiment of wind farm grid-connected.The simulation results verify the effectiveness and correctness of the proposed method.We introduced a self-designed general-purpose real-time simulator and an open converter system as an interface device.Its principles and functions are described in detail.Based on the general real-time simulator and open converter system,the digital physical hybrid simulation experimental platform of wind farm grid connection is designed,the wind farm model is designed in the digital subsystem,and the laboratory power grid and some equipment are designed as physical side subsystems,and the information exchange between the two is realized through the open converter system.Through the digital physical hybrid simulation platform of wind farm connection,the wind farm grid connection experiment and the tracking experiment of wind farm output active power were carried out.Finally,the simulation data are analyzed,and the correctness and effectiveness of the digital-physical hybrid simulation system of grid-connected doubly-fed wind farm studied in this paper are verified.