Design of Adaptive Overcurrent Protection Scheme for a Grid-Integrated Solar PV Microgrid

In recent times the research, development and implementation of renewable energy sources in power networks have increased significantly due to their ability to provide clean, abundant energy as distribution generation units or microgrids operating in grid-connected and islanded modes. The integration of renewable energy sources into the power network has given rise to certain challenges such as the change in minimum fault current level when the microgrid becomes isolated from the main grid (islanding). The main focus of this research is the protection challenge caused by drastic change in fault current in a solar PV microgrid when it transfers from grid-connected to islanded operation and how this challenge can be addressed by adaptive protection. Hence, this paper deals with the design of an adaptive overcurrent protection scheme as well as the coordination of primary and backup relays for faults occurring on the microgrid.