MIS
Microgrid interconnection switch
The switching device that separates a microgrid from the utility for islanding and reconnects it after synchronising.
SLD
Functional block · MLA
Microgrid load-to-island assignment
Functional block · Microgrids
An independently authored application reference. The drawing shows the named function or circuit relationship; use the project legend and selected equipment documentation for its drafting form and connections.
Browse this installation focusIn 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.
- 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.
Read the source: Microgrid operating modes and transitions management
Schematic · MLA
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.
A distinction that matters
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.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Microgrid operating modes and transitions management
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.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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Neutral earthing resistor
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SLD / Schematic
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Microgrid multiple-island control separation
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