Coordinated voltage and frequency control for HVDC sending end under pole-block fault: Using model predictive control

Once the pole-block fault occurs, serious power unbalance takes place in the high-voltage direct current (HVDC) transmission system, which results in severe voltage and frequency deviation. In this situation, to ensure the reliable operation of HVDC sending end, a large amount of power surplus should be dissipated. Regular dispatch schemes like generation shedding cannot always ensure rapidity and optimality and sometimes even lead to stability problems. To address this issue, this paper presents a model predictive control (MPC) scheme for coordinated operation of power sources, including synchronous condenser, battery energy storage system (BESS), and wind farm. It achieves the purpose of optimal voltage control and frequency regulation under HVDC pole-block fault. This scheme has two layers. Based on model predictive control and moving horizon estimation (MHE), the top-layer controller calculates the overall active and reactive power references, which are further fed to the bottom-layer power source controllers for execution. Simulation results demonstrate the effectiveness of the proposed scheme.