An optimal control strategy of VSC-HVDC under unbalanced grid voltage conditions

This paper presents an optimization control strategy for power control of VSC-HVDC under unbalanced grid voltage conditions. For simple implementation and flexible operation, the current references are derived and synthesized into one generalized equation introducing two individually adaptable parameters. The two parameters can be adapted to eliminate the oscillations of instantaneous active and reactive power and the currents at the grid side under unbalanced grid voltage conditions. The optimization method based on PSO algorithm is presented to determine the two parameters. The simulation is carried out with PSCAD/EMTDC, and the results show that proposed strategy is effective and feasible.