Transient Stability Tripping Control Of Sending-end System With Multiple Wind Farm Clusters

The transmission of wind power cluster can not only improve economy but also change the transient stability and control method of the power system. When urgent generator tripping control is needed during a serious fault, it is hard to ensure stable operation of the power system or the cost of tripping generator is too high by only tripping conventional thermal generation units, therefore, in order to maintain the stable and secure operation of power network at a small cost, it is necessary to properly take the wind power farm into account. Based on an actual technical project, this paper studies the transient stability gripping control strategy by taking an actual grid with multiple wind power clusters as the object of the research after analyzing the impact of wind power and thermal power on the grid. The major work of this paper sums up as follows:(1)The mathematical model of wind turbine system is established. Based on analyzing the characteristics of different wind turbines,the wind speed model, wind power model, pitch angle control model, shafting models, generator model, converter model and electrical control model of wind turbine are established respectively, then the models of different wind turbines are established, at last,the method of wind farm dynamic modeling is selected.(2)The transient characteristics of wind power and thermal power are analyzed as well as the influence of urgent generator tripping on the grid. Firstly, based on the equal area rule, the influence of thermal generator tripping on the grid is analyzed from the perspective energy, and the computing method of the quantity of generators to be tripped; Then, the transient characteristics of different kinds of wind farm are analyzed as well as the influence of wind farm tripping on the grid by simulation in an actual grid with multiple wind power clusters.(3)A coordination generator tripping strategy of thermal generation unit and wind farm which apply to the sending end system with multiple wind power clusters is proposed, and the validity of the strategy proposed is verified based on an actual power grid. Firstly, the principles of the selection of thermal generation units and wind farms to be tripped are proposed respectively based on their characteristics, then an algorithm about the priority coefficient of generator tripping is put forward. Based on the priority coefficient of generator tripping, a coordination generator tripping strategy of thermal generation unit and wind farm is proposed aimed at recovering stability and reducing the quantity of generators to be tripped. At last, the validity of the strategy proposed is verified based on an actual power grid, and applicabilities of generator tripping strategy based on thermal generation unit, wind farm and coordination generator tripping strategy of thermal generation unit and wind farm are compared.