# Microgrid synchronising timeout indication

Canonical URL: https://eloragrid.ai/symbols/microgrid-synchronising-timeout-indication
Publisher: Elora Grid
Updated: 2026-11-03
Lookup label: MSTI
Drawing use: Schematic
Reference families: Manufacturer

Representation: Functional block
Installation focus: microgrids
Input: Synchronising state and time
Output: Synchronization timeout

Reports that the assigned synchronising process did not complete within its defined interval.

## In plain English

### What this block does

Reports that the assigned synchronising process did not complete within its defined interval.

### A simple example

In a microgrid reconnecting at its point of common coupling, a synchroniser can adjust the island reference while a separate permissive confirms the permitted relationship across the open breaker. For this reference, the drawing identifies “Synchronising state and time” at the input and “Synchronization timeout” at the output. The alarm should identify the unmet condition.

### What the drawings help you do

Start at the named input: Synchronising state and time. Identify its source device or document and the state represented on the drawing. Follow the named output: Synchronization timeout. Cross-reference its destination and separate the command from confirmation that the equipment responded.

### Terms

- Input: Synchronising state and time
- Output: Synchronization timeout
- Application reference: An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Concept diagram: Synchronising state and time → MSTI → Synchronization timeout
A reading guide. The entry's original illustration and input/output facts describe this application.

- [Microgrid Flex components and control design](https://productinfo.se.com/microgrid_guide/0100db2503_ecostruxure-microgrid-flex_design-guide_iec/English/0100DB2503-Microgrid%20Flex%20Design%20Guide-IEC-Optimize%20%28bookmap%29_DD00654397.XML.xml/%24/MicrogridFlexComponents-3A7DD96C)


## What it represents

Reports that the assigned synchronising process did not complete within its defined interval. Synchronising control compares two AC systems before their assigned connecting breaker closes. Voltage magnitude, frequency, phase relationship, breaker readiness and command authority are separate inputs to the closing decision.
In a microgrid reconnecting at its point of common coupling, a synchroniser can adjust the island reference while a separate permissive confirms the permitted relationship across the open breaker. For this reference, the drawing identifies “Synchronising state and time” at the input and “Synchronization timeout” at the output. The alarm should identify the unmet condition.
Identify the two measurement sides and the equipment receiving any adjustment request. Closing limits, breaker timing and loss-of-measurement behavior require the approved synchronising design. 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: Synchronising state and time. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Synchronization timeout. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- The alarm should identify the unmet condition.
- Identify the two measurement sides and the equipment receiving any adjustment request. Closing limits, breaker timing and loss-of-measurement behavior require the approved synchronising design.

## Information to show or reference

- Label the source and connection reference for synchronising state and time.
- Identify the destination and defined state of synchronization timeout.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: The alarm should identify the unmet condition.

## Important distinction

The alarm should identify the unmet condition. 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: Synchronising state and time
- Output / connection: Synchronization timeout
- Lookup label: MSTI is a library lookup label, not a standard device designation.

## Public references

- [Microgrid Flex components and control design](https://productinfo.se.com/microgrid_guide/0100db2503_ecostruxure-microgrid-flex_design-guide_iec/English/0100DB2503-Microgrid%20Flex%20Design%20Guide-IEC-Optimize%20%28bookmap%29_DD00654397.XML.xml/%24/MicrogridFlexComponents-3A7DD96C) — Schneider Electric. Public technical context for microgrid synchronising interfaces. Microgrid power and control interfaces, synchronisation and source coordination. 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.