Search

There are two critical issues in stabilizing subsynchronous resonance of practical power systems. One is to select an effective yet low-cost control scheme. The other is to optimize the controllers under all possible operating conditions and diversified system disturbances. To address these issues, this article proposes a combined control scheme and a coordinated control design method. The combined scheme is composed of a supplementary excitation damping controller and a voltage source converter based generator terminal subsynchronous damping controller deployed, respectively, on the rotor and stator sides of a generator to take full advantage of a supplementary excitation damping controller (very low cost) and generator terminal subsynchronous damping controller (fast response, flexibility in rating, and deployment). The coordinated control design is implemented through parameter optimization on the linearized system and performance verification with non-linear simulations. The former uses genetic algorithm and simulated annealing to solve the constrained non-linear optimization problem, while the latter inspects the dynamic control performance under either large or small disturbances. A practical system in northern China is taken for a case study. The results of both eigenvalue analysis and time-domain simulation have fully demonstrated the effectiveness of the optimally and coordinately designed subsynchronous resonance control system. [ABSTRACT FROM AUTHOR]