# Microgrid multiple-island control separation Canonical URL: https://eloragrid.ai/symbols/microgrid-multiple-island-control-separation Publisher: Elora Grid Updated: 2026-11-03 Lookup label: MMCS Drawing use: Schematic Reference families: Manufacturer Representation: Functional block Installation focus: microgrids Input: Island assignments Output: Separated island-control scopes Keeps control targets and resource ownership separate for independently energized islands. ## In plain English ### What this block does Keeps control targets and resource ownership separate for independently energized islands. ### A simple example In a microgrid with sectionalized buses, the controller can associate each connected source and load group with its current island. A mode-dependent neutral or protection interface needs its own independently validated design. For this reference, the drawing identifies “Island assignments” at the input and “Separated island-control scopes” at the output. Shared controllers can still be common dependencies. ### What the drawings help you do Start at the named input: Island assignments. Identify its source device or document and the state represented on the drawing. Follow the named output: Separated island-control scopes. Cross-reference its destination and separate the command from confirmation that the equipment responded. ### Terms - Input: Island assignments - Output: Separated island-control scopes - Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections. Concept diagram: Island assignments → MMCS → Separated island-control scopes 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 Keeps control targets and resource ownership separate for independently energized islands. Microgrid topology control tracks which sources and load sections are electrically connected. The same physical installation can form several islands, so source roles, measurement boundaries and earthing interfaces must follow the established configuration. In a microgrid with sectionalized buses, the controller can associate each connected source and load group with its current island. A mode-dependent neutral or protection interface needs its own independently validated design. For this reference, the drawing identifies “Island assignments” at the input and “Separated island-control scopes” at the output. Shared controllers can still be common dependencies. Keep measured switch positions, logical island assignment and any earthing command separate. A conceptual topology block cannot establish a safe neutral-switching arrangement or prove that a circuit is de-energized. 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: Island assignments. Identify its source device or document and the state represented on the drawing. - Follow the named output: Separated island-control scopes. Cross-reference its destination and separate the command from confirmation that the equipment responded. - Shared controllers can still be common dependencies. - Keep measured switch positions, logical island assignment and any earthing command separate. A conceptual topology block cannot establish a safe neutral-switching arrangement or prove that a circuit is de-energized. ## Information to show or reference - Label the source and connection reference for island assignments. - Identify the destination and defined state of separated island-control scopes. - Record the equipment or control-document revision supporting this functional block. - Check this application limit in the project design: Shared controllers can still be common dependencies. ## Important distinction Shared controllers can still be common dependencies. 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: Island assignments - Output / connection: Separated island-control scopes - Lookup label: MMCS 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 topology and earthing coordination. 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.