Funding: US Department of Defense
Multi-LayeredMicrogrid Controller Architecture
As an extension of the Dynamic Control project, and to further support the site's objectives, Fort Hunter Liggett will be converted into a full microgrid through hardware changes and deploying an industrial grade microgrid controller, which uses DER-CAM in the supervisory layer.
The microgrid controller will have a multi-layered distributed architecture (see Multi-Layered Control figure on the right), in which control tasks are distributed among four layers to ensure stable, reliable, and optimized microgrid operation:
- Layer one: A real-time device level control layer acting in the micro-seconds to milli-second range that ensures stable and safe operation of the connected equipment and the network. This will be realized through device level controls of DER, load, and feeder.
- Layer two: A network level automation and data acquisition layer acting in milli-seconds to seconds that supports cluster/plant-level operation.
- Layer three: A supervisory controller layer acting in minutes that optimizes the operation of the system as a whole in grid connected and islanded modes. This layer includes generation, storage and load forecasting, data management, optimum operation scheduling, spinning reserve management, and automatic generation control. This layer is based on Berkeley Lab’s DER-CAM microgrid optimization tool.
- Layer four: A grid interface layer that supports grid interactivity and allows data transfer between the utility and the microgrid.
The microgrid controller will interact with the utility to react to dynamic prices, demand response signals, over-generation limitations, etc.
In the microgrid concept design for Fort Hunter Liggett, the physical structure of the microgrid will also be modular. This design includes several substations that are connected together and to the utility through a MV cable ring. One option for a conceptual one line diagram for one of the substations is shown in the attachment below. (See Single Line Diagram) As shown in that figure, each substation module will include PV generation, battery storage, and diesel backup generation, and will supply the building loads connected to it. This modular structure increases the reliability and reduces maintenance costs for Fort Hunter Liggett.