The time delay exist widely in the power systems such as measuring device, control loops and communicate between measuring device and controllers. This time delays effects on the small signal stability and reduces the low frequency oscillation damping. Hence, should effect of the time delay be study in the design calculations for better efficiency. In this paper, using of the T-S Fuzzy method designing a power system stabilizers in which computes the effect of time delay in the generator terminal voltage. Stabilization conditions express by delay-dependent Lyapunov-Krasovskii functional as the linear matrix inequality (LMI) and determined the controller gains by numerical method. The purposed stabilizer tested on a single machine power system and multi-machine system. The results got compares to the conventional stabilizer that in their designing neglected effect of the time delay. The simulations performed with MATLAB software. The results of simulation shows efficiency the stabilizer purposed comparison to conventional stabilizers.
