A Method of Reduced-Order Modal Computation for Planning Grid Connection of a Large-Scale Wind Farm

For planning the grid connection of a wind farm, small-signal stability needs to be examined to ensure the stability of wind farm as a standalone system. However, for a large-scale wind farm with m wind turbine generators (WTGs), the dimension of state matrix is nm if on average the order of dynamic models of the WTGs is n. Thus, when the number of the WTGs in the wind farm is over several hundred or more, high-dimensional numerical difficulty of modal computation may occur. Therefore, in this paper, we propose a method of reduced-order modal computation for the application in planning the grid connection of the large-scale wind farm. Dimensions of matrices involved in the reduced-order modal computation are m and n such that the numerical difficulty of modal computation is effectively avoided. In the paper, the effectiveness of proposed method of reduced-order modal computation is demonstrated and evaluated by an illustrative simple example wind farm and an example large-scale wind farm with 200 WTGs.