Characteristic Research For Doubly Fed Induction Generator Connected In The Grid

With the increasing severity of energy and environment problems, renewable energy is competitively developed all over the world. Wind energy, which is clean and abundant, is attached great importance to and becomes the fastest developing renewable energy.As the rating of wind power in power network rises, the large wind farms often reach several hundred MW. Unlike the other power plants, the active powr from wind farms varies all the time, which may influence the operation and stability of power network after connection, so for the larger wind power penetration limit of grid, the running characteristic of wind generator will be very significant, especially to its dynamic respone characteristic and transient characteristic. And the doubly fed induction generator(DFIG) based on wind turbine is one of the main stream machine type, then studying its running characteristic connected in the grid( including its steady characteristic, dynamic response characteristic and transient characteristic) has the decisive affect on the stability of grid running. So based on the study of each country grid code requirement, and aimed at the characteristic analysis for DFIG at PSCAD platform using simulating after studying each country code guide, and the high voltage direct current transmission based on voltage source converter( VSC-HVDC) is also import in this paper.In this paper, the wind modeling , wind turbine modeling , converter modeling and control modeling etc. are set up. Using the stator flux directional vector control to realize the decoupling control of the active power and reactive power of DFIG by analyzing the modeling of DFIG.. The DFIG steady characteristic is given based on the theory analysis for the DFIG.. The dynamic response characteristic of DFIG in different wind regime is also simulated by the DFIG directly connected in the great grid. And the simulation result show the right of DFIG system dynamic modeling and its fast dynamic response characteristic, as well as the adjusting capability of reactive power and voltage. In the same time, the DFIG transient characteristic during the grid fault is also present, The VSC-HVDC is used in the wind power transmission , and the insulating to the grid fault help the lower voltage riding through of wind farm.