Discrete-time fractional-order power system stabilizers

This paper introduces a new discrete-time fractional-order power system stabilizers (DTFoPSS) that can be used to stabilize synchronous machines connected to infinite bus subject to both local and inter-area mode of oscillations. The dynamics of the proposed stabilizers are of second-order IIR-type controllers that depend only on the fractional order 0 <; α ≤ 1. The DTFoPSS will be used in both single and multi-machine infinite bus systems triggered by severe disturbances. The flat phase characteristics make the DTFoPSS more appealing to adopt than their integer-order counterparts. They outperformed the continuous integer-order power system stabilizers (IoPSS) in single-machine infinite-bus systems, while exhibit identical performance to that of the IoPSS in multi-machine ones. The main points of this work are demonstrated via numerical simulations.