| With the increasing of wind power penetration and large scale wind power centralized power system,wind power important influence on power system stability.Reasonable of wind farm model is the premise of analyzing the influence of wind power access to power grid.At present,study of static equivalence wind farm is more accurate than the dynamic equivalent research under fault.Output characteristics under fault and dynamic model of wind farms are more complex and important to system,so study of output characteristics under fault of the doubly-fed wind farm and its dynamic model is of great significance.This paper studies the output characteristics under fault of the doubly-fed wind farm and its identification method of dynamic model,the main works are as follows:(1)The detailed mathematical model and general simplified model of the doubly-fed induction generator(DFIG)are analyzed,which provides the theoretical foundation for subsequent equivalent model.(2)The influence of the limits on the output characteristics of DFIG during a Three Phase fault is studied,according to the existing theoretical derivation and simulation data.The mechanism of the characteristics of the steady-state active power output during a fault determined by the active power limit,the rotor current limit and the rated output limit is revealed.(3)Equivalent model of DFIG wind farm is established combined with the theoretical derivation of detailed mathematical model of DFIG and the mechanism of the influence of the limits on the output characteristics of DFIG.On the basis of the analysis of DFIG wind farm equivalent clustering during different fault,this paper proposes a accuracy evaluation method combined with numerical evaluation and situation assessment.Some simulations are implemented to verify the accuracy of the equivalent method.(4)This paper proposes parameters calculating methods of a wind farm equivalent model.The method distinguishes the dominant and non-dominant parameters based on parameter sensitivity analysis.the non-dominant parameters are established by the method of equivalent and the dominant parameters are determined through optimization algorithm.The simulations verify its effectiveness.In this paper,the characteristics under fault of the doubly-fed wind farm and its dynamic model are studied.It puts forward the strategies of effective classifications of wind farm and polymerization methods of parameters,and obtains high accuracy parameter calculating program through the optimization of dominant parameters.The reasonable dynamic model of a DFIG wind farm is established. |
