# Microgrid load-to-island assignment

Canonical URL: https://eloragrid.ai/symbols/microgrid-load-to-island-assignment
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: MLA
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: microgrids
Input: Load and bus connectivity
Output: Load island allocation

Associates each selected load group with its presently connected electrical island.

## In plain English

### What this block does

Associates each selected load group with its presently connected electrical island.

### 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 “Load and bus connectivity” at the input and “Load island allocation” at the output. Load measurements must use the same boundary.

### What the drawings help you do

Start at the named input: Load and bus connectivity. Identify its source device or document and the state represented on the drawing. Follow the named output: Load island allocation. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Load and bus connectivity
- Output: Load island allocation
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Load and bus connectivity → MLA → Load island allocation
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

Associates each selected load group with its presently connected electrical island. 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 “Load and bus connectivity” at the input and “Load island allocation” at the output. Load measurements must use the same boundary.
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: Load and bus connectivity. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Load island allocation. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Load measurements must use the same boundary.
- 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 load and bus connectivity.
- Identify the destination and defined state of load island allocation.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Load measurements must use the same boundary.

## Important distinction

Load measurements must use the same boundary. 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: Load and bus connectivity
- Output / connection: Load island allocation
- Lookup label: MLA 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.