# Microgrid bus-voltage deviation monitor

Canonical URL: https://eloragrid.ai/symbols/microgrid-bus-voltage-deviation-monitor
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: MBDM
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: microgrids
Input: Bus voltage and reference
Output: Voltage deviation information

Reports the difference between the monitored bus voltage and its assigned reference.

## In plain English

### What this block does

Reports the difference between the monitored bus voltage and its assigned reference.

### 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 “Bus voltage and reference” at the input and “Voltage deviation information” at the output. Measurement location matters.

### What the drawings help you do

Start at the named input: Bus voltage and reference. Identify its source device or document and the state represented on the drawing. Follow the named output: Voltage deviation information. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Bus voltage and reference
- Output: Voltage deviation information
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Bus voltage and reference → MBDM → Voltage deviation information
A reading guide. The entry's original illustration and input/output facts describe this application.

- [Microgrid control systems](https://selinc.com/services/microgrids-power-management/microgrid-control-systems/)


## What it represents

Reports the difference between the monitored bus voltage and its assigned reference. 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 “Bus voltage and reference” at the input and “Voltage deviation information” at the output. Measurement location matters.
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: Bus voltage and reference. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Voltage deviation information. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Measurement location matters.
- 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 bus voltage and reference.
- Identify the destination and defined state of voltage deviation information.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Measurement location matters.

## Important distinction

Measurement location matters. 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: Bus voltage and reference
- Output / connection: Voltage deviation information
- Lookup label: MBDM is a library lookup label, not a standard device designation.

## Public references

- [Microgrid control systems](https://selinc.com/services/microgrids-power-management/microgrid-control-systems/) — SEL. 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.

## 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.