Abstract:

To address the risk of system inertia loss and frequency instability caused by grid integration of high-proportioned new energy and unit failures, an N-k robust emergency dispatch method considering dynamic frequency security constraints was proposed. With the consideration of the frequency response characteristics of variable-speed pumped storage, a dynamic frequency response model incorporating variable-speed pumped storage was constructed, and the nadir frequency constraint was established through second-order cone transformation. Information entropy theory was employed to quantify the uncertainty of unit failures, and an uncertainty set considering N-k unit failures was developed. A two-stage robust emergency dispatch model considering N-k failures was established. The upper layer involved preventive unit commitment considering frequency security constraints, and the lower layer simulated post-N-k failure emergency dispatch. The column-and-constraint generation algorithm was used for the efficient solution. The simulation experiments have demonstrated that the proposed model effectively balances system operational economy and frequency security, enhancing the grid's resilience under conditions with complex and multiple failures.

Key words: dynamic frequency security, emergency dispatch, pumped storage, second-order cone, N-k failure, two-stage robust