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Synchronism check
Checks documented synchronising conditions before a permitted connection.
Protection functions
Functional block · MDUI
Microgrid dead-island utility-reconnect 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
Distinguishes the documented dead-island energization case from live-island synchronised reconnection.
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 “Utility and island voltage conditions” at the input and “Assigned reconnect case” at the output. Loss of sensing must not be interpreted as a dead island.
What the drawings help you do
Start at the named input: Utility and island voltage conditions. Identify its source device or document and the state represented on the drawing. Follow the named output: Assigned reconnect case. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Input
- Utility and island voltage conditions
- Output
- Assigned reconnect case
- 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 · MDUI
What it represents
Distinguishes the documented dead-island energization case from live-island synchronised reconnection. 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 “Utility and island voltage conditions” at the input and “Assigned reconnect case” at the output. Loss of sensing must not be interpreted as a dead island.
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: Utility and island voltage conditions. Identify its source device or document and the state represented on the drawing.
- Follow the named output: Assigned reconnect case. Cross-reference its destination and separate the command from confirmation that the equipment responded.
- Loss of sensing must not be interpreted as a dead island.
- 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 utility and island voltage conditions.
- Identify the destination and defined state of assigned reconnect case.
- Record the equipment or control-document revision supporting this functional block.
- Check this application limit in the project design: Loss of sensing must not be interpreted as a dead island.
A distinction that matters
Loss of sensing must not be interpreted as a dead island. 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.
Explore related references
SYNC SCOPE
Synchronoscope
A synchronoscope indicates the phase relationship and relative frequency behaviour of two AC sources.
SLD / Schematic
MDIR
Microgrid dead-utility island-close restraint
Identifies the specified restraint on connecting an energized island to an unavailable utility circuit.
Functional block
Put the reference into a drawing workflow.
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