Decentralized frequency control of restructured energy system using hybrid intelligent algorithm and non-linear fractional order proportional integral derivative controller

The emergence of micro-sources in the energy market to reduce carbon emissions and exploit more renewable generations increases the frequency oscillations of the system. Hence, this paper attempts to develop a robust nonlinear fractional order proportional integral derivative (NLFOPID) controller for frequency regulation of restructured energy systems. A hybrid atom search-particle swarm optimization (AS-PSO) is proposed to optimize the gain values of the NLFOPID controller. The proposed control approach enhances flexibility by providing robustness against the RE intermittency. The optimization technique is coded in MATLAB and applied for frequency regulation of a multi-area energy system developed in Simulink. Initially, the effectiveness of the hybrid algorithm is validated for standard benchmark functions and then implemented for frequency control. The results demonstrate that the proffered AS-PSO technique performs significantly for various types of transactions in a deregulated energy market than state-of-the-art. The real-time applicability of the proposed controller is validated using hardware-in-the-loop simulation of the open energy market in OPAL-RT. The frequency response obtained from the AS-PSO optimized NLFOPID controller is remarkable compared to other techniques. Furthermore, the closed-loop stability of the system is examined using bode analysis through an improved Oustaloup approximation technique.