Student Energy Research Spotlight: IImplementation of Active and Reactive Power Flow

By LT Kanavaros Dimitrios

Microgrid is a synthesized term originating from the Greek word mikros, which means small, and grid. The synthesized word indicates that a microgrid is a miniature of the main grid, and its main purpose is to operate autonomously and to increase the reliability of the power system in a naval installation. Two types of power are flowing from the utility to the microgrid and vice-versa: 1) active power, which is the real power that can be transformed from electric to non-electric by the loads; and 2) reactive power, which doesn’t do real work but is required by electric motors. The presence of the latter category lessens the energy efficiency of our installation, reduces the real energy, and increases the cost of the electricity for the consumer.

One way to compensate for the reactive power and to simultaneously control the active power is usage of a highly developed electronic system called the energy management system (EMS). The EMS manages the distributed energy resources (DERs) in a microgrid, such as solar panels and batteries, to ensure that electricity is available to an installation when the main grid is off (e.g. blackout). The EMS operates the microgrid in grid-connected mode, or 
in islanding mode. 

In our research, four different methods of EMS control have been examined in order to regulate the active and reactive power flow from the source in a single-phase microgrid when it operates in grid-connected mode. Experimental measurements validate the simulated results, and as a consequence three of those different kinds of controls have accomplished the maximum desired efficiency. This means that the microgrid can compensate for reactive power, and simultaneously manage the active power. This contributes to the reduction of the cost of the electricity and to the delivery of the maximum available power to 
the consumer.

ABOUT THE AUTHOR

LT Dimitrios Kanavaros is a Greek naval officer and a student in the Electrical Engineering Department of the Naval Postgraduate School. Contact Dr. Giovanna Oriti at goriti@nps.edu for more information about this research.