This project demonstrated a microgrid control framework creating a centrally managed dispatchable generation hub as the power base for networked utility feeder interconnected facilities. The dispatchable generation hub is a microgrid managing diesel-based energy generation, renewable generation, demand, and storage assets for power export to support the demand of closely sited military installations.

Technology Description

The technology solution demonstrated provided a microgrid control architecture constituted of commercial-off-the-shelf controllers, protection relays and switchgear suitable for all Medium Voltage (MV) distribution with MV/Low Voltage (LV) generation assets. The modifications made in installing the control framework were limited to upgrades of equipment like legacy backup generators (to make them dispatchable) and manual switches (to enable automation) at the utility point of connection. The over-the-fence connection of the microgrid required extensive interaction with the region’s utility provider, Consumers Energy, and an amendment to the existing interconnect agreement. The system design was based on two backup generators, photovoltaics (current and ongoing development) and an energy storage system optimized for power applications.

Demonstration Results

The successful field demonstration verified autonomous microgrid power quality management (frequency, voltage, reactive power compensation) to respond to grid conditions or control signals with planned energy storage. Prediction and compensation for intermittencies from renewable energy was demonstrated using energy storage to maintain power quality in islanded and grid-connected modes with efficient use of generators during sustained intermittencies and non-optimal (cloud covered or light wind) periods.

Implementation Issues

The greatest risk to adoption and enterprise wide success for the demonstrated solution is regulatory compliance. The value from the monetization of the distributed energy resources and demand response capability of the demonstration must meet the intertie and parallel operating requirements of States, territories and regions where the system would operate, including but not limited to, Institute of Electrical and Electronics Engineers 1547 and American National Standards Institute C84.1, and specifically complying with Michigan Public Service Commission R460.601 – R460.656 under the jurisdiction of the Michigan Public Service Commission. This could manifest as emissions abatement, renewable penetration limits and mission impeding demand response requirements.

A potential disadvantage with implementation of the demonstrated system is the installation of required switchgear and protection to existing backup generation. Backup generation as standby generation has limited protection and switching hardware. When the backup distributed generation is intertied with the distribution there are increased protection and switching hardware that add cost and complexity. This cost can be mitigated by performing optimization simulations and studies to determine the generation vs cost tradeoff for each installation.