Application of SCA Tuned FOPID Controller for LFC of Multi-area and Multi-unit Power System with RES Incorporating V2G Technology

Climate change is one of the greatest challenges in the 21^st century as our traditional electric generating units are generally thermal power plants, which emit lots of carbon to the environment. So, for the clean and sustainable energy, attention is given on the integration of renewable energy sources like solar energy, wind energy and hydro energy etc. into the grid. Renewable energy sources (RES) are intermittent in nature. Hence, for an uninterruptible power supply, it demands a battery energy storage system (BESS). Electric vehicles are the best BESS for system stabilization. This paper investigates the load frequency control (LFC) of three area system consisting of diverse generation sources with integration of RES incorporating vehicle to grid (V2G) technology and considering nonlinearities like generation rate constraint (GRC) and time delay (TD) under load fluctuation. The RES considered in this is study is solar thermal power plant (STPP). At first, proportional integral derivative (PID) controller is used as the secondary controller and the gains of the PID controller are tuned by the particle swarm optimization (PSO) algorithm but the controller fails to stabilize such a complicated system. So, the improved version of PID controller, known as fractional order PID (FOPID) controller is introduced and tuned by the PSO and sine cosine algorithm (SCA) independently. For implementing the optimization technique, integral time absolute error (ITAE) is used as the objective function. The response parameters of the frequency and tie-line power are analyzed with PSO tuned FOPID and SCA tuned FOPID controller and it is found that SCA tuned FOPID controller outperforms the other controller.

I. INTRODUCTION

Present day power system (PS) is a highly complex electrical network. It comprises of generation, distribution and transmission of the electric power. As the load differs from time to time, there is fluctuation of the tie line power and frequency. In electrical power network, frequency and tie-line power should remain within the scheduled limit for reliable power supply. Hence, it is necessary to always maintain the balance between generation and demand of the electrical power and the technique by which it is achieved is known as LFC.