Analysis And Research On Dynamic Simulation Of Double-fed Inductive Wind Generators Connected With Grid

Recently, with the rapid development of the manufacture of power electronic device and its application, large-scale variable speed constant frequency (VSCF)wind units has become one of main technology aspects. However, VSCF double-fed wind units which can connect wind units to power systems flexibly become the mainstream machine model of wind power exploitation at present. Therefore, concerning on the technique of VSCF double-fed wind units, its operation characteristic and the study of power system security and stability on the grid-connected system, and so on, have yet become important investigative direction of wind power field correspondingly. Based on the overseas datum, the dynamic modeling, operation characteristic, along with the stability of wind generators connecting to grid on sustaining the disturb of wind speed, system fault and so on, are studied.The main disquisitive content and production of the thesis are as follows:(1) The dynamic mathematic model of double-fed inductive wind power system used to simulate and analysis is established, including of wind turbine model, double-fed inductive wind generator model(consist of convertor model), and wind model as prime mover. The principle of catching most wind energy and the control theory of ac-dc-ac convertor are analyzed in detail.(2) Using the software flat roof of MATLAB/SIMULINK, the characteristic of wind speed and wind turbine are simulated. At the base of mathematic model, digital simulating tool of VSCF wind power system is built. As ramp wind,gust wind,random wind example, simulated and studied the run characteristic of wind farm which consisted of seven 1500kW double-fed inductive wind generators connected to grid. At the same time, the output characteristic of wind generator and impact on system when the voltage of system fell and fault occurred are analyzed.(3) The content of the thesis is a part of shanxi science and technology tackle key problem item "The study of operation technology of wind power system of shanxi province". This item is invested by shanxi international power group limited company. Through the evaluation of wind energy resource and its can development value, maked out the pre-feasible study report. The wind farm of shuozhou pinglu area is planed to put into production at the end of 2007 year. Combining the item, the impact on operation of shuozhou power system after wind farm of some capacitance connected to it are simulated and analyzed. By uniting MATLAB and PSASP, the output characteristic of double-fed inductive wind generators is simulated and the transient stability of shuozhou power system including wind farm of some capacitance when wind generators bore wind disturb, start-up and halt suddenly is analyzed. Conclude that because double-fed wind generator has preferable control system, its output characteristic is good and the impact on power system is very small, the power system can ensure transient stabilization.Through studying the characteristic of every part of VSCF wind units, this paper built the whole dynamic mathematic model of VSCF wind generator. At the same time, the simulation model which could simulate VSCF wind units dynamic characteristic is established using MATLAB/Simulink. As 10.5MW wind farm connected with system example, aiming at the mode of ramp wind,gust wind,random mode, the voltage of system falling and fault occurring, made simulating VSWT with large capacity of MW level. The result of simulation make out that the model is correct and valid, also illuminate that the predominant operation characteristic of VSCF DFIG. And that the simulation flat based on MATLAB which this paper build provides corresponding technology auspice and analysis means for studying VSCF wind turbine further and establish favorable foundation for the future.