Improving the Transient Stability of AC System by Emergency Power Control of MTDC System

With the depletion of non-renewable energy and the increasing environmental pollution, the scale of new energy power generation and direct current transmission continues to expand in the power grid, resulting in a significant reduction in the effective inertia of the power system. Therefore, the transient stability of the AC/DC hybrid system formed after the multi-terminal direct current system (MTDC) based on the voltage source converter (VSC) connected to the power grid has become particularly prominent. This paper tries to improve the transient stability of AC system by adopting model predictive control (MPC) for emergency power control of MTDC. Firstly, the linearization model of the AC/DC hybrid system is obtained by linearizing the MTDC model near the stable equilibrium point. The design scheme of model predictive controller for MTDC system is obtained by using linearization model and adopting the model predictive control theory, which uses the minimum rotor speed difference among generators as the control target. The simulations of a 3generator 9-bus AC/DC hybrid system have demonstrated that the proposed method can improve the transient stability of AC/DC hybrid system.