Research On Active Power Control Strategy Of Wind Farm With DFIGs

Wind Power, as the most widely used and mature of all renewable energy, has got greatly development in recent years. Because of the volatility and randomicity of wind power, the impact of wind power on the security, stability and economy of power system becomes more apparent than ever with the steadily increasing penetration of wind power into the grid. Against that background, it is of great practical significance and practical value to research the active power control strategy of wind farm with double-fed wind turbines. The main content of this thesis is as follows:(1) Combined with the operation principle of DFIG, its mathematical model is established, which including wind speed model, aerodynamics model, shaft system model, pitch angle control model, generator model and control system model.(2) For the Power Systems with DFIG-based Wind Farms, the impact of wind speed fluctuation, DFIG wind turbine inertia control and reactive control mode on system frequency dynamic characteristic are analyzed, respectively. PSS/E is taken as the simulation platform.(3) One strategy of wind farm active power regulation considering system frequency regulation demand and the corresponding wind power regulate method are proposed, then to support the system frequency stability according to the system frequency regulation demand and reduce the abnormal time of system frequency.(4) Aiming to the practical problem of active power constraint of wind farm cluster, one method for the active output optimal distribute of wind farm cluster is proposed, which is based on the short-term wind power prediction. The impact of short-term wind power prediction error and the power loss in tie-line are considered in the method. Genetic algorithm is applied to solve the optimization problem. The validity and feasibility of the method is verified through the actual data from a wind farm cluster in China.