Performance Analysis of Directional Overcurrent Protection in Multi Source Microgrid

Microgrid applications including renewable energy sources have been spreading around the world for decades. Although integration of distributed generators has numerous benefits from the view points of utilities and customers, it causes some technical challenges resulted from bidirectional power flow, variable load and fault current levels, occurring of islanding etc. Many protection schemes are introduced to provide protection against these challenging conditions. Overcurrent (OC) relay is one of the mostly used methods against excessive overcurrent conditions due to short circuit or overload conditions. Also directional overcurrent (DOC) protection is able to provide better performance using the direction of the fault current. In this paper, the performance of DOC relay is analyzed under different operating conditions of a microgrid including PV power plant, a battery storage (BS) and a diesel generator. Matlab/Simulink was used for simulation studies. The main aim of the study is to define the strong and weak points of overcurrent protection. Results are obtained from simulation studies.