Research On Renovation Technology Of Electric Control System For Building Grid-friendly Wind Turbines

As the operation time of wind turbines increases gradually,more and more problems are exposed.Wind farms urgently need to transform and upgrade the functions of old wind turbines,so as to improve the generation efficiency of wind turbines,enhance the adaptability of wind turbines to the power grid and build grid-friendly wind turbines.The topic of this thesis comes from the reform of the electric control system of Huaneng International Taobei wind farm.Firstly,the thesis analyzes the main problems existing in wind farm units,and then studies these problems from three aspects of improving power generation efficiency,enhancing voltage adaptability and frequency adaptability.Secondly,the technical methods of software and hardware modification and simulation model design are put forward for simulation test.Finally,the actual transformation and testing are carried out,and the results are analyzed..In terms of improving the power generation efficiency,the control strategy is mainly optimized to expand the wind speed range of the wind turbine operating in the blade tip speed ratio state.In this thesis,a statistical average algorithm for automatically correcting the optimal blade tip speed ratio is proposed,and the simulation model is designed by Bladed software to verify the correctness and validity of the technical method.A modification scheme for different main controllers is designed on the hardware.In terms of enhancing voltage adaptability,this thesis studies the high voltage crossing technology based on virtual impedance and reactive power absorption,and designs a simulation model to simulate the occurrence of high voltage through Matlab/simulink software as well as obtains good simulation results.The chopper circuit is designed on the hardware.In terms of frequency adaptability,this thesis studies the virtual synchronous generator technology and primary frequency modulation requirements.Based on the whole controller of wind power virtual synchronous machine,the judge condition and control strategy of primary frequency modulation are designed.The primary frequency modulation scheme and the reference value of key parameters are proposed as well as the RTDS test platform and three transformation schemes to realize VSG are designed.After that,the reconstruction scheme was applied to the actual wind farm reconstruction and good results were achieved.The purpose of transforming the wind turbines at Huaneng International Taobei wind farm into grind-friendly wind turbines was realized.