Experimental Demonstration of a Tiered Power Management System for Economic Operation of Grid-Tied Microgrids

Power management of grid-tied microgrids including distributed generations (DGs) and storage devices can be challenging due to the intermittent and uncontrollable nature of many types of DGs, load variations in time, different grid power tariffs, availability of different options to balance the electric supply and demand, and other parameters. In order to operate a microgrid efficiently, the management system should accomplish two tasks. 1) It needs to be adaptive and optimize the microgrid´s performance by defining long-term (daily-based) directives or control strategies. 2) The management system should be able to operate and control the microgrid in real time and satisfy all operational constraints. To address the above-mentioned tasks, a comprehensive power management system that includes two control layers is developed in this paper. Concept for the proposed power management policy was demonstrated on an experimental microgrid system composed of lead-acid batteries, photovoltaic (PV) system, 3-kW peak load, and a utility connection.