Stability enhancement using SMES and robust nonlinear control

The transient stability control of a power system is a typical nonlinear control problem. Although many controller design approaches have been developed, most of the existing controllers are designed by using linear control theory. In this paper, a nonlinear robust controller for the excitation and a thyristor-controlled superconducting magnetic energy storage (SMES) unit is proposed to enhance the transient stability of a power system with unknown or varying parameters like the equivalent reactance of the transmission lines. The SMES unit is located near the generator bus terminal in a power system. The authors´ simulation results demonstrate that the proposed controller can ensure the transient stability of a single machine infinite bus power system under large faults that may occur near the generator bus terminal