Grid Characteristic Research Under Large-scale Integration Of Wind Power

At present, the problem of the global conventional energy shortage and the environmental degradation has been attracting more and more attention by the people from all over the world. The large-scale development and utilization of new energy is an effective way to solve the above problems, such as the wind power. The capacity of global wind power increases with each passing day, at the same time, the scale of wind capacity integrated into grid expands year by year. Because of the output power of wind farm is fluctuating and difficult to accurately forecast. So the wind power integration can produce adverse impact about the safe and stable running of power grids, and with the continuous increasing scale of wind power integration, the impact of wind power output fluctuation for power grid stability is more serious. If the problem of large-scale wind power integration has not been solved well can severely restricts the development of global wind power,therefore, it is necessary to study the impact of grid characteristics when large-scale wind power integrated into grid.In this thesis, the permanent magnet direct-drive type wind farm equivalent model and six nodes wind power system model were set up based on the Matlab/Simulink software platform. The influence of wind power distribution and wind power penetration on power system's voltage characteristic was simulated and analysed through above models. And combine the principle of complex system brittleness and the theory cellular automata, the wind power system's brittleness was studied. And the fault evolution rule was obtained when power system is affected by the wind power.Firstly, consider the influence of wake effect and the 150MW permanent magnet direct-drive type wind farm equivalent model was set up by homology equivalence method.The reliability of the equivalent wind farm was simulated and shown through the equivalent wind farm interconnection grid power system model. The correctness of the equivalent method in this thesis was indicated, and a reliable wind power model in the subsequent study was provided on the impact of grid voltage when the wind power integrated into grid.Secondly,the six nodes wind power system model was set up. The 150MW wind farm equivalent model which has been built was connected with the different nodes in power system. The influence of power system's voltage characteristic about the wind power distribution was simulated and studied. The strength of the different nodes was obtained and the best point of common coupled was confirmed. Provide the theory basis for choosing the best point of common coupled in practical engineering wind farm.Again, the different capacity of wind farm equivalent model by the equivalence method in this thesis were set up. And these different capacity of wind farm equivalent model were connected with node 4 and node 6 in the six nodes power system. The influence of power system's voltage characteristic on wind power penetration was simulated and studied. And the wind power penetration limitation of this power system was determined.Finally, Based on the theory of complex system brittleness and the principle of cellular automata, the six nodes power system's brittleness was researched. The power system's brittleness excitation propagation path (fault chain reaction) after the wind disturbance by power flow calculation was determined. Prove that it is a very effective method using the principle of cellular automata to study the wind power system's brittleness. Provide a reliable theory basis for the study on grid's breakdown that contains wind power in practical engineering.