Directional overcurrent
An overcurrent function with a documented direction criterion.
Supervises transient or intermittent earth-fault behaviour in the documented feeder application.
Supervises transient or intermittent earth-fault behaviour in the documented feeder application.
The drafting record should connect this function to the residual-current and voltage measurements and earthing-system reference, then trace the intermittent-fault operating element and affected feeder trip. Keep the complete designation and equipment tag together so that the SLD, relay logic and terminal schedule describe the same implementation.
The cited mapping is a public manufacturer example (ABB Relion 620 function mapping). Suffixes are not universal equivalences across products, and this reference supplies neither a protection setting nor certification of the selected scheme.
ABB's 67NIEF application treats intermittent fault behaviour; continuous residual overcurrent is a separate protection criterion.
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Public primary-source function or application mapping used to identify this designation; wording and drafting notes are original.
Device-number and suffix convention. This page is not a reproduction of the full licensed standard.
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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