Implementing a microgrid using standard utility control equipment

The Duke Energy McAlpine Creek Substation in Charlotte, North Carolina, has been a test bed for smart grid and renewable generation technology since 2006. The area just outside the substation fence houses a 50 kW photovoltaic installation as well as a 240 kW, 500 kWh battery energy storage system (BESS). These two assets are connected in parallel to import and export energy to a distribution circuit fed from the substation. Recent weather events and the drive to develop more renewable generation on the grid have led to extensive efforts in developing microgrids that can provide resiliency for those being served and potentially provide economic benefits for the owner and utility. In 2013, Duke Energy decided to integrate their renewable resources at the McAlpine Creek Substation to provide backup generation services to an adjacent fire station while allowing use of the BESS for grid support services when grid-connected. This effort was completed in 2015. One goal was to develop a model to allow construction and support using standard Duke Energy distribution equipment and off-the-shelf components where possible to allow more integrated support. This paper describes the design, construction, and commissioning of the microgrid controls for the McAlpine Creek microgrid project and lessons learned from its implementation.