Research On Impact Of Large Grid-Connected Wind Farms To The System And Maximum Setting Capacity

The wind power is a kind of renewable green power resources. The wind energy is developing fastest among all kinds of renewable resources. The characteristic of wind resource is the randomicity of the magnitude and direction of wind speed. The power output of a wind power plant is fluctuant and intermittent, which is determined by the instability and intermittence of wind speed, so it will produce severe influence to voltage quality and stability of the power system. With the development of wind industry in the world, more wind turbine generators are used in wind farms, the percentage of wind power in the power system has been increasing and the influence which large grid-connected wind farms bring to the power system will be more remarkable. As a result, researches on characteristics of grid-connected wind farms and the maximum setting capability of wind farms become an important issue crying for solving.The major research and contributions are as follows:(1)The influences which large grid-connected wind farms bring to the power system are analyzed roundly and thoroughly. The influence on power system stability is the emphasis.(2)Common dynamic mathematic models of wind speed and wind turbine are introduced. Reduced order model of wind farms is built.(3)The indices that weight the scale of wind farms are analyzed. The main factors and actual research methods about the maximum setting capacity of wind farms are also discussed.(4)With Power System Analysis Toolbox, the paper analyses the influence of operation of the power system by time domain simulation. The simulation results show that system voltage will keep varying with the change of the wind plant's power output.(5) The results on IEEE New England 39-bus system gained from time domain simulation and power flow calculation show that the fluctuation of bus voltage will increase along with the increase of grid-connected capacity of wind farms.