Adaptive overcurrent protection for microgrids in extensive distribution systems

Microgrid is regarded as a new form to integrate the increasing penetration of distributed generation units (DGs) in the extensive distribution systems. This paper proposes an adaptive overcurrent protection strategy for a microgrid network. The protection coordination of the overcurrent relays is treated as a linear programming problem for the different operation states. In the control center, an artificial neural network (ANN) model is trained with real-time measurements to identify the states whether there is a fault on the line segment. Fault location is estimated further with the same measurements in another neural network model. Reconfigurations can be performed to modify the settings of the on-field relays to enhance the reliable operation for the different operational situations. The test results show that the adaptive overcurrent protection scheme with the assistance of estimation model can modify the protective settings for the new operation state accurately and intelligently.