Robust nonlinear co-ordinated excitation and TCSC control for power systems

A robust nonlinear co-ordinated generator excitation and thyristor-controlled series capacitor (TCSC) controller is proposed to enhance the transient stability of power systems. For the convenience of modelling, the TCSC is located at the midpoint of the transmission lines in a power system. A nonlinear feedback law for the generator is first found, which linearises and decouples the power-system model. Robust nonlinear control theory is then employed to design the nonlinear co-ordinated controller that consists of two controllers, the generator excitation and the TCSC controllers. The proposed co-ordinated controller is designed, based on local measurements, and the design of the resulting controllers is independent of the operating point. Simulation results show that the proposed controller can ensure transient stability of the power system under a large sudden fault, which may occur at the generator busbar terminal