AC/DC Hybrid Power System Damping Control Based on Estimated Model Predictive Control Considering the Real-Time LCC-HVDC Stability

High Voltage Direct Current (HVDC) can quickly vary its power to damp power system angle oscillation. To handle the uncertainties of the faults and the system model, it is necessary to estimate the real-time linearized model of the AC/DC Hybrid system. This leads to two problems: Firstly, after the fault, the HVDC will quickly evolve to a steady state and, therefore, result in an unobservable control matrix. Secondly, the HVDC power should not exceed its stable range limited by the post-fault system. To address the above issues, the main novelties are as follows: First, this paper proposes a novel system identification method to handle that case when there is no control input excitation. Second, this paper presents a control strategy that fully considers the real-time stability constraints of the HVDC. More specifically, this paper estimates the system matrix and the control matrix separately. Based on the linearized model of the AC/DC hybrid system, the control matrix is calculated using the sensitivities of the active powers of the generators concerning those of the HVDC. Then, the system matrix is estimated using measures of the power angle and frequency. Finally, by processing the local voltage and current measurements, the system-side Thevenin equivalent parameters on the HVDC connecting point are estimated in real time and the regulating bound of the HVDC is determined. According to the linearized model and the HVDC power bound, a model predictive control strategy is used to damp the oscillation. Simulation results reveal the effectiveness of the proposed strategy.