Practical Implementation of Hybrid Energy Systems for Small Loads in Rural South Africa

Abstract

Hybrid renewable energy systems (HRESs), are alternative off-grid methods of generating power to remote rural areas, where power lines are not economically viable. Most of the research studies on renewable hybrid systems or microgrids (MGs) in South Africa, focus mainly on the optimal sizing and optimal control of different systems, by making use of renewable energy simulation softwares, however, there is a lack of research carried out on the implementation of these hybrid systems in real time. The aim is to develop a real time control method for an isolated hybrid system submitted to a variable load, as well as resources. The first step towards achieving this aim, was to critically review available published research works, to describe recent developments in improving the optimum operating concept of microgrid controllers for stand-alone or grid-connected systems. Secondly, to investigate any real-time implementation established by either hierarchical or distributed control. Then to, analyze their reliability and functionality in practical set up of the controller, in managing power in the system to the variable load. The study provided a brief overview of microgrid prototype systems, microgrid controls, operating modes and multi-DER microgrid types built into a hybrid system, which introduces a number of strategies or techniques for managing remote rural application prototypes in an isolated or grid-connected system. However, hierarchical control was found to be more appropriate for large microgrids with multiple types of distributed energy resources (DERs), compared to distributed control, particularly when combined with energy storage systems (ESSs), in isolated mode. The rising of hybrid system controllers in real-time renewable energy for the optimum energy management system (EMS), required the design of a real-time controller to operate the entire system in real time. Increasing popularity of renewable energy (RE) has a control strategy that determined the overall efficiency of the hybrid system (HS), although the energy management system of these systems is particularly complex to be managed. The study's main contribution is to investigate the feasible controller and, later, to present an advanced control strategy for managing and controlling the flow of hybrid renewable energy with a diesel generator (DG) and battery (BT) as a backup in a rural application of SA. EMS would be implemented, using a fuzzy logic controller (FLC) in MATLAB / SIMULINK. This study analysed input and output variables for the design of a controller, with a set of rules and a three-dimension (3D) surface. Simulation results of related studies with different objectives were analysed, with the aim of sussing out an appropriate controller for the current study. Arduino Mega was used for coding and uploaded to the implementation of practical implementation of the study. The system operated successfully by supplying the load. This study finally answered the question of the feasibility of the controller in real-time applications.