Construction And Application Of Simplified Equivalent Model Of Wind Farm Considering Wind Conditions

Wind energy has been paid more and more attention in recent years for its clean and renewable characteristics. With the rapid development of wind power and increasing of wind farm scale, influence of large scale wind power which was integrated on the grid to the power system's safe operation and electrical energy quality is also growing, it is urgent to carry out wind power system simulation method. And the capacity of doubly fed wind turbine unit is relatively small, large-scale wind power bases commonly has total of up to thousands of wind turbines, building model for every turbine will complicate the analysis and increase simulation time of the power system, making a more complicated analysis for the power system. In view of this problem, this paper considers to build simplified equivalent model for the wind farm, and then explores the application of the equivalent model on the wind power system security and stability analysis, mainly to do the following research:(1) Take consideration of the interaction between wind turbines, establish a wind speed calculation model for every wind turbine under the influence of the wake effect and wind direction, and based on the wind speed differences between the wind turbines, apply clustering algorithm to group the wind turbines. Finally, considering the characteristics of electric circuit of the wind turbines to make an equivalence of the wind turbines cluster. With this process, a complicate wind farm is simplified to be a simple wind farm with a small number of wind turbines, and its number is determined by the cluster of wind speed.(2) Apply the equivalent model of wind farm on wind power system analysis, based on decision tree classification algorithm, a power system security assessment program is built, the program can orientate the system operation weak point under the contingency, and based on the weak point, give an analysis of power system operation security boundary with changing of wind farm output and the system load.(3) In the light of the weak point of the system, carry out the spare reactive power compensation rules based on trajectory sensitivity of system, and when the standby system reactive power is insufficient, suggest to add additional compensation capacitor group in fault voltage node to achieve low voltage control and prevention of the system weak point under anticipated faults.(4) Create a complete wind power system security and stability assessment and control system. This system include wind farm equivalent, wind power system security evaluation, and the system operation weak point prevention control scheme, provide a reference for the wind power system analysis from not only model building but also analysis methods.