# Microgrid grid-forming reference selection Canonical URL: https://eloragrid.ai/symbols/microgrid-grid-forming-reference-selection Publisher: Elora Grid Updated: 2026-11-03 Lookup label: MGRS Drawing use: Schematic Reference families: Manufacturer Representation: Functional block Installation focus: microgrids Input: Grid-forming resource availability Output: Selected island reference Selects the available source assigned to establish the island voltage and frequency reference. ## In plain English ### What this block does Selects the available source assigned to establish the island voltage and frequency reference. ### A simple example In a microgrid serving a switchroom and industrial loads, the controller can move between grid-connected and islanded operating states only through its defined transition logic. Each state needs identifiable source roles and feedback. For this reference, the drawing identifies “Grid-forming resource availability” at the input and “Selected island reference” at the output. Reference transfer requires a validated control scheme. ### What the drawings help you do Start at the named input: Grid-forming resource availability. Identify its source device or document and the state represented on the drawing. Follow the named output: Selected island reference. Cross-reference its destination and separate the command from confirmation that the equipment responded. ### Terms - Input: Grid-forming resource availability - Output: Selected island reference - Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections. Concept diagram: Grid-forming resource availability → MGRS → Selected island reference A reading guide. The entry's original illustration and input/output facts describe this application. - [Microgrid operating modes and transitions management](https://productinfo.se.com/emol_functional_specifications/doca0371_emol_functionalspecifications/EN/DOCA0371_EMOL_Functional_Specifications_DD00894746.xml/%24/EMOL_OperatingModesandTransitionsManagement_DD00895904) ## What it represents Selects the available source assigned to establish the island voltage and frequency reference. A microgrid operating-mode function coordinates how local sources and loads relate to the utility connection. The selected mode, the measured electrical condition and the actual switching configuration can differ during a transition. In a microgrid serving a switchroom and industrial loads, the controller can move between grid-connected and islanded operating states only through its defined transition logic. Each state needs identifiable source roles and feedback. For this reference, the drawing identifies “Grid-forming resource availability” at the input and “Selected island reference” at the output. Reference transfer requires a validated control scheme. Show the requested mode, entry conditions, completion feedback and failure indication. These functional blocks explain control responsibilities and do not specify a ready-to-use operating sequence or grid-connection approval. The functional block is an independent explanation of this named application. Equipment-specific ratings, terminal connections and operating conditions must be established in the project documentation. ## How to read it - Start at the named input: Grid-forming resource availability. Identify its source device or document and the state represented on the drawing. - Follow the named output: Selected island reference. Cross-reference its destination and separate the command from confirmation that the equipment responded. - Reference transfer requires a validated control scheme. - Show the requested mode, entry conditions, completion feedback and failure indication. These functional blocks explain control responsibilities and do not specify a ready-to-use operating sequence or grid-connection approval. ## Information to show or reference - Label the source and connection reference for grid-forming resource availability. - Identify the destination and defined state of selected island reference. - Record the equipment or control-document revision supporting this functional block. - Check this application limit in the project design: Reference transfer requires a validated control scheme. ## Important distinction Reference transfer requires a validated control scheme. This reference describes the named application; it does not establish a new IEC graphical symbol, an ANSI device-function number or an exact manufacturer connection diagram. ## Facts - Representation: Functional block - Installation focus: Microgrids - Input / boundary: Grid-forming resource availability - Output / connection: Selected island reference - Lookup label: MGRS is a library lookup label, not a standard device designation. ## Public references - [Microgrid operating modes and transitions management](https://productinfo.se.com/emol_functional_specifications/doca0371_emol_functionalspecifications/EN/DOCA0371_EMOL_Functional_Specifications_DD00894746.xml/%24/EMOL_OperatingModesandTransitionsManagement_DD00895904) — Schneider Electric. Public technical context for microgrid operating-mode controls. Grid-connected and island modes, transitions, topology and authority. The application text and educational graphic are independently authored; the publisher does not certify this representation. ## Graphic scope Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.