Research On Strategy Of DFIG Participate In Power System Frequency Regulation

Wind Power, as the most widely used and mature of all renewable energy, has got greatly development in recent years. Because of the uncontrollable and randomness of wind power, it brings great influences to power system frequency with the steadily increasing penetration of wind power into the grid. Especially, the vector control mode of DFIG makes the rotor speed and grid frequency decoupling, and this makes worse to grid frequency. Thus, on the base of the analysis of influence of DFIG integrated into grid to power system frequency, the strategy of DFIG participate in power system frequency regulation is proposed, and it’s of great theoretical significance and useful value. The main content of this thesis is as follows:(1) Study the operation principle of DFIG and establish the mathematical model, including wind speed model, aerodynamics model, shaft system model, pitch angle control model, generator model and control system model;(2) analysis the influence of various factors (wind power fluctuations, reactive power control model, the unit type and wind power penetration) on the grid frequency after DFIG integrated into gird; then considering of wind power economics, put forward the strategy of DFIG participate in power system, and discuss the frequency regulation ability of this control strategy by an actual simulation system;(3) propose the evaluation method of economic benefits of grid integrated wind power when DFIG participating in power system frequency regulation, considering of generating revenue, generating cost, ancillary service costs, environmental benefits and the demand of system frequency-regulating, and it’s verified by an example. This more fully confirmed the efficiency of the suggested strategy in economic.