With large scale dispersed generation integrated into distribution network

the classical load model is no longer able to describe the dynamics of the generalized synthesis load with distributed energy resources integration. To solve this problem

a simplified model of direct-drive permanent-magnet(DDPM)wind turbine is proposed

which neglects the mechanical subsystem in the generic model of DDPM wind turbine. The combination of particle swarm optimization method and Levenberg-Marquardt method is used to estimate the simplified model parameters

and the model adaptability is also studied. Furthermore

the simplified DDPM wind turbine model and the classical load model are paralleled to illustrate the generalized synthesis load in the distribution network. The parameter identifiability and estimation difficulty of the generalized synthesis load model is analyzed according to trajectory sensitivities. The parameters are estimated according to different levels of voltage dip and different levels of wind power ratios. The effects of distribution network equivalent parameters on estimation accuracy are discussed. The estimation results have validated the applicability of the proposed modeling method. This work is supported by National Natural Science Foundation of China(No. 51190102).