RMU
Ring main unit
A secondary-distribution switchgear assembly with a selected combination of switching functions.
GA objects
Symbols · FPI
Fault passage indicator
Device on an MV cable or overhead feeder that shows whether fault current has passed its location, to speed fault finding.
In plain English
What does Fault passage indicator mean?
A fault passage indicator senses current at a point on a medium-voltage feeder and shows, with a flag or LED, when fault current has passed. Operators follow the indicators along a feeder to find the faulted section between the last operated indicator and the first unoperated one.
A simple example
Indicators may sense phase faults, earth faults or both, and many can signal remotely to SCADA. The symbol does not show the sensing method, reset method or thresholds, which must suit the network earthing and feeder load to avoid false or missed indications.
What the drawings help you do
Check whether the indicator covers phase faults, earth faults or both. Note any remote signalling output. A fault passage indicator only signals; a protection relay trips a breaker.
This particular reference
Device on an MV cable or overhead feeder that shows whether fault current has passed its location, to speed fault finding. A fault passage indicator only signals; a protection relay trips a breaker.
- Phase
- One of the related AC waveforms in a power system.
- Signal
- Electrical information passed between devices, rather than necessarily the main power supply.
- Rating
- A value stating the conditions for which equipment is specified.
Read the source: Secondary-distribution switchgear and ring main units
SLD / Schematic · FPI
What it represents
A fault passage indicator senses current at a point on a medium-voltage feeder and shows, with a flag or LED, when fault current has passed. Operators follow the indicators along a feeder to find the faulted section between the last operated indicator and the first unoperated one.
Indicators may sense phase faults, earth faults or both, and many can signal remotely to SCADA. The symbol does not show the sensing method, reset method or thresholds, which must suit the network earthing and feeder load to avoid false or missed indications.
How to read it
- Check whether the indicator covers phase faults, earth faults or both.
- Note any remote signalling output.
Information to show or reference
- State fault types detected
- State reset method
- Reference SCADA signal
A distinction that matters
A fault passage indicator only signals; a protection relay trips a breaker.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Secondary-distribution switchgear and ring main units
Public secondary-distribution switchgear and ring main unit context where fault indicators are fitted.
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. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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