CONTROL OF MINIGRID

Abstract

The remote areas far away from grid supply are electrified by the autonomous power supply which are based on diesel-engine generator sets and work at relatively high cost. Integration of renewable energy sources (RESs), such as, photovoltaic (PV) and wind, with autonomous system can substantially reduce the cost of electricity generation. Therefore the hybrid power generation and forming the minigrid could be the best solution for electrification of remote areas. In this report, a wind diesel hybrid system is developed for the study purpose and it’s MATLAB/ SIMULINK model is analyzed for the voltage and frequency variation through the simulation results at variable wind speed and changing load conditions. Three control methodologies are proposed, for voltage control, over frequency control and under frequency control of this hybrid system. Capacitor bank is used for the voltage control, a controlled secondary dump load in the coordination of discrete frequency controller is proposed for over frequency control and a power balance controller is proposed for under frequency control of the system. All the three controls are implemented in the model and model is simulated for all the conditions like wind only, wind diesel, diesel only modes of operation and the results for all the cases were analyzed for frequency and voltage variation. Voltage and Frequency variations are found well under the allowable range of ± 3% and thereby proposed control methodologies are validated by simulation results in the MATLAB/SIMULINK software and these controllers can be used in the wind diesel hybrid system.