Microgrid: Control techniques and modeling

This paper presents a discussion on the control techniques required for microgrid operation and implements a simple control strategy in a microgrid model realized with Matlab. The modeling and control strategy are kept elementary. This is done in order to use developed model for teaching and student training purpose for power system curriculum in undergraduate courses. The model is helpful in introducing the microgrid concept, its advantages and operating modes, to the students, and for highlighting the basic control issues of a microgrid. The control issues related with power quality events and pre-set conditions which disconnect microgrid from the main grid and leads the microgrid in a separate islanded mode are discussed. To demonstrate the operation of a microgrid in islanded mode, the authors have simulated showing that the same is connected with the main grid and simultaneously sharing critical and non-critical loads. After being switched over to islanding mode, automatically it eliminates the non-critical loads and continues to supply power to the critical loads. The power supplied by the main grid and the microgrid are observed and studied. The authors present the issues relating to the islanded operation of microgrid including coordination of microsources and storage device to maintain the satisfactory islanding operation of microgrid.