Fractional-Order Load Frequency Control of a Two-Area Interconnected Power System with Uncertain Actuator Nonlinearities

Abstract

Nonlinearities in power system cause severe degradation in quality of power being generated. A robust controller is often needed to compensate for uncertainties caused by nonlinear components present in the control loop. In this paper, a robust fractional order controller is designed and investigated for tackling with inherent nonlinearities in an interconnected two-area non-reheated thermal power system. The presence of these inherent nonlinearities is due to generation rate constraint (GRC) and governor deadband (GDB), which can cause delayed disturbance rejection and/or sustained oscillations in power system variables. On considering both nonlinearities simultaneously into account, the complexity in controlling the power system increases, and conventionally optimized controllers fail to produce satisfactory dynamic performance. To address these issues, a robust fractional-order-proportional-integral-derivative (FOPID) controller has been designed utilizing a lately introduced Salp Swarm Algorithm (SSA). Extensive simulation studies have been performed and comparative studies have been drawn with controllers designed with available techniques in literature. Based on investigations carried out in the article, it is found that SSA optimized FOPID shows remarkable enhancement investigated in load frequency control performance of investigated plant in presence of significant parametric variations in comparison with particle swarm optimization optimized controllers.