Research For Inertia Response Of Wind Turbine Connected With Grid By Optimizing Phase-locked Loop

There will be more and more wind power in the grid, and its percentage increases, as wind power technology develops. It means wind power replaces parts of synchronous generators in traditional grid. Currently, wind turbine synchronizes with gird through Phase-Locked Loop(PLL), and PLL with the fast response shields the dynamic variation of grid frequency. It results in the problem of wind turbine does not response to the fluctuation of grid frequency, which means that wind turbine can't present inertia to grid. As wind power goes more, the rotational inertia of grid decreases. The fluctuation of frequency will become wide caused by the imbalance of active power. It might influence the operation of equipment in grid. On the other hand, the start of synchronous generators' primary frequency response need some of time. Therefore, wind turbine presents inertia has the great significance for wind power increases in gird and enhance the stability of gird.This paper focuses in Doubly-Fed Induction Generator(DFIG) Wind Turbine and Full Capacity Wind Turbine(FCWT), proposes the inertial control strategy for each based on optimizing the PLL. The rotational kinetic energy stored in mechanical system of wind turbine can be transferred to electrical energy exported into grid, which means wind turbine has ability of inertial response. Analysis the operating principle of inertia control for each by the response behavior of internal potential. For DFIG, it can present inertia by merely optimizing PLL. However, for FCWT, because of decoupled with grid, in order to realize inertial control, it needs introducing the phase-locked error to regulate the commander of speed controller. It also discusses the principle of optimizing PLL. And verifies the inertial control strategy through simulation on MATLAB/SIMULINK. Design and construct the simulation experimental platform of DFIG based on d SPACE system. Simulate the static and dynamic characters of the actual wind turbine, and verify the inertial control by optimizing PLL effective in practical application through connected to simulation grid in laboratory of power system dynamic simulation.