In view of the common subsynchronous oscillation (SSO) controller incapability of suiting the time-varying and nonlinear characteristics of power system

the cosine migration model

the premature judging mechanism

the mutative scale of chaos mutation strategy

and re-scheduling operations are introduced into the improved biogeography-based optimization (IBBO) algorithm to design subsynchronous damping controller (SSDC) optimally based on the mechanism of suppressing SSO by static var compensator (SVC). Finally

eigenvalue analysis and electromagnetic simulation are conducted to verify the effectiveness of the controller developed. The simulation analysis of Jinjie Plant indicates that SVC-SSDC optimized by the IBBO algorithm can greatly improve the damping of the three torsional modes and thus effectively depress the multimodal SSO

ensuring stability of the system and safety of the generator shafts. Moreover

The IBBO algorithm has a faster search speed and higher search accuracy in searching for the optimal control parameters compared with the traditional biogeography-based optimization (BBO) algorithm

the particle swarm optimization (PSO) algorithm

as well as the genetic algorithm (GA).