The Research Of Wind Farm Internal Harmonics

With the development of wind energy technology, DFIG-based wind power generator and PSMG-based wind power generator have been widely used. Considering many wind farms are composed by doubly-fed wind power generator and direct-driven wind power generator,also,there are many wind farms composed by doubly-fed wind power generator. When the wind speed is low, DFIG working in subsynchronous state, the converter absorb power. Power flowing between hypersynchronous state DFIG (including PSMG-based wind power generator) and subsynchronous state DFIG will cause more harmonic problems which need to be tested and simulated.The paper analyze general structure of wind power generator, also including the function of each part. On the basis of this study, analyze the structure of wind power generator which being used nowadays. Also including the structure and connection mode of wind farm which using different type of wind power generator. Analyze the working principle of wind turbine transforming wind energy into mechanical energy. On the basis of this study, analyze the principle of influence caused by wake effect between wind turbines. Analyze the wind power generator arrangement principle which cause wake effect. It can prove that different wind energy absorbing caused by wake effect and different wind speed can make influence to the power output of each wind power generator.This paper analyze the structure of doubly-fed wind power generator and direct-driven wind power generator, including generator mathematical model, type of convertor, the structure, characteristic and control strategy of convertor. Analyze4kinds of working state which DFIG can run. Also including existence condition, power flowing of each working state. It means that all the analysis above can take a further step for power flowing research between wind power generators. Use Matlab to build2kinds of wind power generator model, also analyze the detail of control model. Analyze the instantaneous reactive power theory. According to the theory of instantaneous reactive power, also build a testing model which can be used for harmonics testing in wind farm model. Build wind farm model in certain structure, set different conditions(including wind speed and quantity of wind power generator),to simulate and calculate internal harmonics. Conclude the change rule of internal harmonics by the change of wind speed and wind power generator quantity.