Study on the physical mechanism and the fast algorithm of ATC constrained by transient stability for the point-to-grid transmission system

With the planning and constructing of UHV grid in China, some huge thermal plant bases are going to be connected to the receiving grid via UHV transmission lines. Therefore, it is significant and urgent to study the ATC (available transfer capability) of the point-to-grid transmission system quickly for each connection scheme in planning stage. In the paper, firstly, the physical mechanism of ATC constrained by transient stability is analyzed in depth. Secondly, the analytical solution of the ATC constrained by transient stability is proposed on the basis of the physical mechanism analysis. Thirdly, a fast feasible algorithm of the ATC constrained by transient stability is proposed, and the algorithm is independent of the electro-mechanical time domain simulation software. At last, the result of the proposed algorithm is compared with that of the conventional algorithm for the given point-to-grid UHV transmission case, and the correctness and the effectiveness of the proposed algorithm are verified.