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Synchronism check
Checks documented synchronising conditions before a permitted connection.
Protection functions
Functional block · MSSI
Microgrid synchronising source-ownership interface
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
Assigns the resource controller allowed to adjust the island reference during synchronising.
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 “Resource authority state” at the input and “Synchronising adjustment ownership” at the output. Conflicting controllers can issue incompatible demands.
What the drawings help you do
Start at the named input: Resource authority state. Identify its source device or document and the state represented on the drawing. Follow the named output: Synchronising adjustment ownership. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Resource authority state
- Output
- Synchronising adjustment ownership
- 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 Flex components and control design
Schematic · MSSI
What it represents
Assigns the resource controller allowed to adjust the island reference during synchronising. 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 “Resource authority state” at the input and “Synchronising adjustment ownership” at the output. Conflicting controllers can issue incompatible demands.
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: Resource authority state. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Synchronising adjustment ownership. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Conflicting controllers can issue incompatible demands.
- 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 resource authority state.
- Identify the destination and defined state of synchronising adjustment ownership.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Conflicting controllers can issue incompatible demands.
A distinction that matters
Conflicting controllers can issue incompatible demands. 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 Flex components and control design
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.
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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