Research On Wind Turbine Failure Analysis And Equivalent Model Of Wind Farm

In recent years,with the growing wind power installed capacity in power system,the characteristics of wind turbine which is connected to the grid gains increasing attention.Doubly-fed induction generator(DFIG)has been widely used in wind power generation market.In this paper,the failure characteristics of doubly-fed induction generator,the short circuit current calculation in distribution network which contains doubly-fed induction generator as distributed power supply,the equivalent model of wind farm which connected to grid with large installed capacity are studied in detail.Achieved results are as follows:1)It presents the basic operation principles of doubly-fed induction generator.The control strategies of converters,including grid side converter and rotor side converter,are introduced.Based on the mathematic model of DFIG,the failure characteristics of DFIG with or without crowbar resistance are analyzed according to the different terminal voltage dip.Finally,the analysis results are simulated.2)As for the distribution network containing DFIG,the voltage controlled current source equivalent model was built which is according with newest grid-tied code.Additionally,the node voltage function of the distribution network which containing DFIGs is built with short circuit occurs.In consideration of the non-linear relationship between the fault voltage and fault current,an iterative correction method was presented to solve the function.The case verified the method presented in this chapter.3)An equivalent model for wind farm is proposed in this chapter in consideration of the wake effect and low-voltage ride through demand.The different input wind speed caused by wake effect is used as a clustering index.The wind farm equivalent model is put forward by the aggregation method.And the validation process is also proposed.Finally,summarize the whole paper and point out the thesis which should be deserved more attention in the future.