# Microgrid external dispatch request boundary

Canonical URL: https://eloragrid.ai/symbols/microgrid-external-dispatch-request-boundary
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: MEDRB
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: microgrids
Input: External dispatch message
Output: Site dispatch request

Identifies the documented interface receiving an external site power request.

## In plain English

### What this block does

Identifies the documented interface receiving an external site power request.

### A simple example

In a microgrid control room, the operator can see source availability, active constraints and current operating mode. A communication failure should remain distinguishable from an electrical resource failure. For this reference, the drawing identifies “External dispatch message” at the input and “Site dispatch request” at the output. The request is subject to site authority and limits.

### What the drawings help you do

Start at the named input: External dispatch message. Identify its source device or document and the state represented on the drawing. Follow the named output: Site dispatch request. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: External dispatch message
- Output: Site dispatch request
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: External dispatch message → MEDRB → Site dispatch request
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

Identifies the documented interface receiving an external site power request. Microgrid supervision coordinates measurements, control authority and resource communication without replacing local protection. Each resource value needs a named measurement boundary, freshness condition and intended control use.
In a microgrid control room, the operator can see source availability, active constraints and current operating mode. A communication failure should remain distinguishable from an electrical resource failure. For this reference, the drawing identifies “External dispatch message” at the input and “Site dispatch request” at the output. The request is subject to site authority and limits.
Identify signal ownership, quality flags, control priority and loss-of-data behavior. These functional references do not certify cyber security, closed-loop performance or equipment interoperability. 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: External dispatch message. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Site dispatch request. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- The request is subject to site authority and limits.
- Identify signal ownership, quality flags, control priority and loss-of-data behavior. These functional references do not certify cyber security, closed-loop performance or equipment interoperability.

## Information to show or reference

- Label the source and connection reference for external dispatch message.
- Identify the destination and defined state of site dispatch request.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: The request is subject to site authority and limits.

## Important distinction

The request is subject to site authority and limits. 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: External dispatch message
- Output / connection: Site dispatch request
- Lookup label: MEDRB 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 supervisory and communication interfaces. 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.