With an increase of wind power penetration rate

the influence of system frequency stability due to wind power cannot be ignored. Firstly

the concept of “sensitive frequency band” is defined. In order to find the frequency characteristic difference between power disturbances with different frequencies

the frequency response model of single machine system is analyzed. Secondly

considering the nonlinear characteristics of complex power systems

the method of cluster scanning is proposed to recognize the sensitive frequency bands of complex power systems. Finally

the method of analysis of the influence of wind power fluctuation on the frequency characteristics of power system by analyzing the sensitive frequency band is given. The existence of a sensitive frequency band is verified by an example of the Northeast power grid. Its influence on the grid power is evaluated by referring to the amplitude frequency characteristics of the wind power fluctuation and the effectiveness of the proposed method.