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Microgrid Building Blocks
Year: 2023 | Author: Haris Bin Ashraf | Paper: H5.1
Fig. 1. Modified IEEE 13-node system used as a microgrid to demonstrate the MBB concept.
plug-n-playequipment blocks that can be interconnected to build a microgrid. These MBBs are a collection of standardized interfaces, control and protection functions, and hardware that is required to build a microgrid. Figure 1 shows an example of a microgrid -- the modified IEEE 13-node system in which all the sources and loads work together in a collaborative fashion.
MBBs integrate three blocks: control, power processing, and communications. The most crucial piece is the control block, which can be a combination of different parts depending on what equipment is being controlled. To make it generally applicable, the control block is divided into three parts. The first part is for steady-state control -- the power flow in the microgrid is managed according to a unified set of rules to ensure power balance with a steady-state operating point, while meeting optimum target objectives such as maximum renewable energy utilization, minimum downtime, and cost considerations. The second part is for dynamic control -- the controller responds to small and large signal transients to ensure stability. The third part is for switching on and off various loads, capacitor banks, or transformer taps.
The power processing block can also have different flavors depending on the nature of equipment. In the case of sources, it can be a power converter or synchronous generator. In the case of loads, or capacitor banks, it can be a switch. Lastly, the communication block is a remote terminal unit that sends and receives data across all MBBs. It serves the purpose of exchanging control commands and measurements.
An experimental test setup is designed based on Fig. 1 to validate the MBB concept. Several types of application will be tested to prove that MBBs can work together in different scenarios of sources and loads connected together. Special cases such as blackstart and mode of operation changes will also be studied.
With the MBB concept, every component connected to the microgrid takes part in maintenance of the power and energy balance, establishment of voltage and frequency, small-signal stability, changes in mode of operation, transient load changes, and protection to fulfill the primary objective of maintaining the integrity of the microgrid bus.
