Protection functions · 67N

Directional neutral-overcurrent

Supervises neutral or residual overcurrent with a documented directional criterion.

SLD / Schematic · 67NDirectional neutral-overcurrent: original educational illustration
Original educational illustrationNot to scale · See source and graphic notes

What it represents

Supervises neutral or residual overcurrent with a documented directional criterion.

The drafting record should connect this function to the residual/neutral CT source and the selected polarising quantity, then trace the directional earth-fault element and feeder trip path. 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 (SEL public device-number table). Suffixes are not universal equivalences across products, and this reference supplies neither a protection setting nor certification of the selected scheme.

How to read it

  • Identify the residual/neutral CT source and the selected polarising quantity.
  • Trace the directional earth-fault element and feeder trip path.

Information to show or reference

  • Label the residual/neutral CT source and the selected polarising quantity.
  • Cross-reference the directional earth-fault element and feeder trip path.
  • Retain the complete suffix, selected device tag and manufacturer manual revision.

A distinction that matters

67N requires both a current criterion and direction information; a neutral current magnitude alone does not provide direction.

Sources you can follow

These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.

ANSI device-number and suffix reference table

Public primary-source function or application mapping used to identify this designation; wording and drafting notes are original.

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

IEEE C37.2-2022: power-system device function numbers

Device-number and suffix convention. This page is not a reproduction of the full licensed standard.

IEEE · 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. 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.

Entry JSON · Entry Markdown · Last editorial update: 13 October 2026

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