Characterization and dimension reduction method for feasible region of nonlinear power system tie line

The invention discloses a characterization and dimensionality reduction method for a feasible region of a tie line of a nonlinear power system. The characterization and dimensionality reduction method comprises the following steps: 1) solving a feasible region polyhedron of tie line power by using a multi-section boundary approximation model; 2) identifying a vertex of a tie line power feasible region; 3) clustering the tie lines based on the coupling sensitivity; 4) translating all planes of the feasible region polyhedron R to obtain a plurality of new boundary points meeting constraint conditions, and writing new boundaries into the boundary set V to obtain a new boundary set; 5) establishing a new polyhedron based on the new boundary set; and 6) judging whether the difference between the feasible region polyhedron and the new polyhedron is smaller than a preset condition, and if so, obtaining the feasible region Rnew of the electric power system tie line. The method can effectively approach the feasible re