Operation of a Micro-Grid in Islanded and Grid-Connected Modes with Advanced Protection Coordination System

Abstract

Improving the reliability, resiliency, and efficiency of the power system is necessary for continuing the power supply to customers whether residential or commercial. Therefore, the use of micro-grid is one of the most crucial solutions for meeting these requirements due to its capability to operate in grid-connected and islanded modes based on the system requirements. However, due to micro-grid operational modes capability, the protection coordination systems encounter a difficulty in detecting faults due to the change in the power system configuration which leads to significant difference in the level of the fault current between each mode because the fault is fed by two sides in the first mode, while in the second mode is only by the micro-grid. This project proposes a method of re-coordinating the overcurrent relay settings based on the operation mode of the micro-grid by performing a MATLAB code to monitor the switch position of the system operational mode and sends a signal to automatic switch to select the appropriate settings for the overcurrent relay. The proposed solution is simulated on a simple micro-grid by using MATLAB-SUMLINK. Furthermore, the results validate the effective performance of the proposed solution in both operation modes of the micro-grid.