Microgrid

A microgrid is a local electrical grid with defined electrical boundaries, acting as a single and controllable entity.[1] It is able to operate in grid-connected and in island mode.[2][3] A 'stand-alone microgrid' or 'isolated microgrid' only operates off-the-grid and cannot be connected to a wider electric power system.[4] Very small microgrids are called nanogrids.[5]

A grid-connected microgrid normally operates connected to and synchronous with the traditional wide area synchronous grid (macrogrid), but is able to disconnect from the interconnected grid and to function autonomously in "island mode" as technical or economic conditions dictate.[6] In this way, they improve the security of supply within the microgrid cell, and can supply emergency power, changing between island and connected modes.[6] This kind of grids are called 'islandable microgrids'.[7]

A stand-alone microgrid has its own sources of electricity, supplemented with an energy storage system. They are used where power transmission and distribution from a major centralized energy source is too far and costly to operate.[1] They offer an option for rural electrification in remote areas and on smaller geographical islands.[4] A stand-alone microgrid can effectively integrate various sources of distributed generation (DG), especially renewable energy sources (RES).[1]

Control and protection are difficulties to microgrids, as all ancillary services for system stabilization must be generated within the microgrid and low short-circuit levels can be challenging for selective operation of the protection systems. An important feature is also to provide multiple useful energy needs, such as heating and cooling besides electricity, since this allows energy carrier substitution and increased energy efficiency due to waste heat utilization for heating, domestic hot water, and cooling purposes (cross sectoral energy usage).[8]

  1. ^ a b c Hu, J.; Lanzon, A. (2019). "Distributed finite-time consensus control for heterogeneous battery energy storage systems in droop-controlled microgrids". IEEE Transactions on Smart Grid. 10 (5): 4751–4761. doi:10.1109/TSG.2018.2868112. S2CID 117469364.
  2. ^ What are Microgrids and Why are They Becoming so Popular? Enchanted Rock, March 2023
  3. ^ Cite error: The named reference IEV was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference iec-isolated_microgrid was invoked but never defined (see the help page).
  5. ^ Burmester, Daniel; Rayudu, Ramesh; Seah, Winston; Akinyele, Daniel (January 2017). "A review of nanogrid topologies and technologies". Renewable and Sustainable Energy Reviews. 67: 760–775. Bibcode:2017RSERv..67..760B. doi:10.1016/j.rser.2016.09.073. ISSN 1364-0321.
  6. ^ a b Hu, J.; Bhowmick, P. (2020). "A consensus-based robust secondary voltage and frequency control scheme for islanded microgrids". International Journal of Electrical Power & Energy Systems. 116: 105575. Bibcode:2020IJEPE.11605575H. doi:10.1016/j.ijepes.2019.105575. S2CID 208837689.
  7. ^ Cite error: The named reference vehicle-grid-berkely was invoked but never defined (see the help page).
  8. ^ "Features and Benefits - Microgrids". www.districtenergy.org. Retrieved 2018-06-28.