Stabilizing control of series capacitor compensated power system on the basis of reduced order model

This paper investigates the control design method to stabilize the multi-mode torsional oscillations due to subsynchronous resonance (SSR), at the same time to improve dynamic transient stability of a capacitor compensated power system. The reduced order model to design controls is derived based on two kinds of reduction methods, the time-scale decomposition method and the balanced realization method. The controls are designed by solving the pole assignment and the optimal regulator problems to slow and fast subsystems, respectively. The designed controllers provide proper damping to all oscillating modes and a swing mode simultaneously. Some numerical simulations show the effectiveness of the proposed design method. The comparative study is presented by different control devices, the supplementary excitation control, superconducting magnetic energy storage (SMES) or variable series capacitor (VSrC).