This paper describes a novel power system stabilizer based on fuzzy logic theory (FLPSS) for damping power system
oscillations focusing on inter-area modes. In particular, the adaptive fuzzy power system stabilizers using both off-line
and on-line training. The determination of the associated domains of the fuzzy logic power system stabilizer is obtained
by off-line training using a pre-designed optimal controller. Computer simulations for a test power system when su bjected
to small disturbances under normal and stressed operating conditions are carried out. The digital simulation results
show that the proposed controller proves its effectiveness and improves the system damping when compared to a
lead-lag and an optimal power system stabilizer controllers.