Supplementary damping control of VSC-HVDC transmission system using a novel heuristic dynamic programming

Inter-area oscillation is a main challenge for secure and stable operation of large-scale interconnected AC/DC power system. In this paper, an innovative adaptive dynamic programming approach, namely goal representation heuristic dynamic programming (GrHDP), was proposed to design supplementary damping controller (SDC) of voltage source converter HVDC (VSC-HVDC) transmission system to suppress inter-area oscillation in large-scale AC/DC power system. Based on the two neural networks structure of HDP, GrHDP developed a new goal representation network, able to automatically generate internal adaptive reward signal to facilitate better mapping between system state and control action. Therefore, GrHDP-SDC could significantly improve dynamic performance of power system. Not necessarily knowing exact mathematic model of the power system, GrHDP-SDC possessed quick learning and universal control characteristics and strong adaptability, superior to conventional lead-lag SDC. Case study was performed based on a two-area four-machine power system with VSC-HVDC transmission line. Conventional lead-lag SDC and HDP-SDC were also studied for comparison. Simulation results show that the proposed GrHDP-SDC has better performance in damping inter-area oscillation than that of conventional lead-lag SDC and HDP-SDC in a wide range of system operating conditions