Functional block · BRO

Breaker-failure retrip output

Functional block · Substations

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.

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In plain English

What this block does

Issues the documented repeat opening request before the assigned backup trip action.

A simple example

In a substation feeder bay, local current and voltage measurements may combine with a remote-end signal before the protection issues the assigned trip request. Backup actions use their own defined initiations and supervision. For this reference, the drawing identifies “Breaker-failure state” at the input and “Assigned breaker retrip” at the output. Retrip and upstream backup have different destinations.

Breaker-failure stateBROAssigned breaker retrip
A reading guide. The entry's original illustration and input/output facts describe this application.

What the drawings help you do

Start at the named input: Breaker-failure state. Identify its source device or document and the state represented on the drawing. Follow the named output: Assigned breaker retrip. Cross-reference its destination and separate the command from confirmation that the equipment responded.

Input
Breaker-failure state
Output
Assigned breaker retrip
Application reference
An explanation of a named drawing function or circuit relationship; the project documents define the equipment and its connections.

Read the source: SEL-411L line differential protection overview

Schematic · BROBreaker-failure retrip output: original educational illustration
Original educational illustrationSee source and graphic notes

What it represents

Issues the documented repeat opening request before the assigned backup trip action. A protection scheme combines measurements, decision elements and communication or trip outputs to protect a defined part of the network. A function number names a job; the scheme interface shows how that job connects to other equipment.

In a substation feeder bay, local current and voltage measurements may combine with a remote-end signal before the protection issues the assigned trip request. Backup actions use their own defined initiations and supervision. For this reference, the drawing identifies “Breaker-failure state” at the input and “Assigned breaker retrip” at the output. Retrip and upstream backup have different destinations.

Keep each protected zone, initiating quantity, blocking signal and trip destination distinct. Settings, communication performance and coordination require the approved protection study and selected relay documentation. 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: Breaker-failure state. Identify its source device or document and the state represented on the drawing.
  • Follow the named output: Assigned breaker retrip. Cross-reference its destination and separate the command from confirmation that the equipment responded.
  • Retrip and upstream backup have different destinations.
  • Keep each protected zone, initiating quantity, blocking signal and trip destination distinct. Settings, communication performance and coordination require the approved protection study and selected relay documentation.

Information to show or reference

  • Label the source and connection reference for breaker-failure state.
  • Identify the destination and defined state of assigned breaker retrip.
  • Record the equipment or control-document revision supporting this functional block.
  • Check this application limit in the project design: Retrip and upstream backup have different destinations.

A distinction that matters

Retrip and upstream backup have different destinations. 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.

SEL-411L line differential protection overview

Public technical context for substation protection scheme interfaces. Line protection, breaker failure, communications and protection coordination. The application text and educational graphic are independently authored; the publisher does not certify this representation.

Schweitzer Engineering Laboratories · Public reference checked 13 October 2026 · Link only

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.

Entry JSON · Entry Markdown · Last editorial update: 3 November 2026

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