Dead-zone robust adaptive controller for FACTS using Quadratic and Non-Quadratic Lyapunov Functions

Robust adaptive control techniques have always been used in numerous industrial applications. In this paper, the dead-zone technique is used to damp growing oscillations in flexible AC transmission systems (FACTS) which is regarded as a new control mechanism for FACTS. The developed controller will overcome the arising problems due to the uncertainty of system parameters and disturbances acting on the system by limiting the error signal of the terminal load voltage within a prescribed region named the dead-zone. This is achieved by adaptive tuning of the PI-controller parameters using Quadratic Lyapunov Function (QLF) and Non-Quadratic Lyapunov Function (NQLF). FACTS model used is a 14th order state-space model of a power network equipped a Static VAR Compensator (SVC). Simulation results, obtained using MATLAB/SIMULINK program, are illustrated for both controllers and compared to confirm the capability of the suggested control techniques in restoring system dynamic stability and improving system performance.