A Nonlinear Coordinated Control Strategy for AC/DC Interconnected Power Systems

A nonlinear coordinated control strategy for improving the transient stability of AC/DC interconnected power systems is presented in this paper. First, an observation decoupled state space model of AC/DC interconnected power systems, which allows estimation or computation of the state components from local measurement, is developed. Secondly, the nonlinear coordinated control rules for HVDC links and generator excitations are derived using optimal-variable-aim strategy (OVAS), which not only improves the first swing stability, but also effectively damps the subsequent power oscillation. Finally, the simulation results of a three-machine six-bus system show that the proposed method can enough use the capabilities of fast response and short-time overload of HVDC links and generator excitations to improve the transient stability of AC/DC interconnected power systems.