GFM
Grid-forming inverter
An inverter controlled as a voltage source that sets its own voltage and frequency, able to energise and hold up an island.
SLD
Functional block · MIRE
Microgrid island reactive-load estimate
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 the monitored island loads with their defined reactive-demand estimate.
A simple example
In an islanded microgrid, the assigned reference source supports bus voltage while other compatible resources share reactive demand according to the selected control method. Grid-connected operation can use a different objective at the PCC. For this reference, the drawing identifies “Island load measurements” at the input and “Reactive-demand estimate” at the output. Load behavior can change with voltage.
What the drawings help you do
Start at the named input: Island load measurements. Identify its source device or document and the state represented on the drawing. Follow the named output: Reactive-demand estimate. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Island load measurements
- Output
- Reactive-demand estimate
- 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 control systems
Schematic · MIRE
What it represents
Associates the monitored island loads with their defined reactive-demand estimate. Voltage and reactive-power control coordinate the AC operating condition of the microgrid resources. A voltage target, reactive-power target and power-factor target represent different control objectives and should have explicit ownership.
In an islanded microgrid, the assigned reference source supports bus voltage while other compatible resources share reactive demand according to the selected control method. Grid-connected operation can use a different objective at the PCC. For this reference, the drawing identifies “Island load measurements” at the input and “Reactive-demand estimate” at the output. Load behavior can change with voltage.
Show each measured quantity, target and resource capability limit. Control-loop tuning, equipment capability and parallel operation require a validated design rather than an assumed property of the symbol. 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 load measurements. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Reactive-demand estimate. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Load behavior can change with voltage.
- Show each measured quantity, target and resource capability limit. Control-loop tuning, equipment capability and parallel operation require a validated design rather than an assumed property of the symbol.
Information to show or reference
- Label the source and connection reference for island load measurements.
- Identify the destination and defined state of reactive-demand estimate.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Load behavior can change with voltage.
A distinction that matters
Load behavior can change with voltage. 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 control systems
Public technical context for microgrid voltage and reactive-power controls. Active and reactive power, generation, load control, operating reserves and system supervision. 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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Functional block
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