{"schemaVersion":1,"slug":"67nief-transient-or-intermittent-earth-fault-protection","name":"Transient or intermittent earth-fault protection","kind":"function","abbreviation":"67NIEF","aliases":["intermittent earth fault","transient earth fault","INTRPTEF","ANSI 67NIEF","IEEE 67NIEF"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEEE / ANSI","Manufacturer"],"summary":"Supervises transient or intermittent earth-fault behaviour in the documented feeder application.","description":["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."],"readingNotes":["Identify the residual-current and voltage measurements and earthing-system reference.","Trace the intermittent-fault operating element and affected feeder trip."],"drawingChecklist":["Label the residual-current and voltage measurements and earthing-system reference.","Cross-reference the intermittent-fault operating element and affected feeder trip.","Retain the complete suffix, selected device tag and manufacturer manual revision."],"distinction":"ABB's 67NIEF application treats intermittent fault behaviour; continuous residual overcurrent is a separate protection criterion.","facts":[{"label":"Function designation","value":"67NIEF"},{"label":"Base function","value":"67 — Directional overcurrent"},{"label":"Published mapping","value":"ABB Relion 620 function mapping"},{"label":"Suffix scope","value":"Application or manufacturer specific; check the complete drawing legend and selected device manual."}],"references":[{"sourceId":"pub-function-abb-mappings","relevance":"Public primary-source function or application mapping used to identify this designation; wording and drafting notes are original."},{"sourceId":"ieee-functions","relevance":"Device-number and suffix convention. This page is not a reproduction of the full licensed standard."}],"related":["67-directional-overcurrent","current-transformer"],"artwork":"pub-function-box","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/protection-functions/67nief-transient-or-intermittent-earth-fault-protection","illustration":{"url":"https://eloragrid.ai/library/illustrations/67nief-transient-or-intermittent-earth-fault-protection.svg","scope":"Original educational concept; not an official standard graphic or product footprint","license":"https://creativecommons.org/licenses/by/4.0/"},"sources":[{"id":"pub-function-abb-mappings","title":"Relion 620 series: published protection function and designation mappings","publisher":"ABB","url":"https://techdoc.relays.protection-control.abb/r/620-series-IEC-60870-5-103-Point-List-Manual/2.0-FP1-IEC/en-US/Functions-codes-and-symbols","type":"manufacturer","scope":"Manufacturer mapping of function names, IEC identifiers and ANSI labels. These are examples for a documented product family, not universal equivalences between standards or products.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Public primary-source function or application mapping used to identify this designation; wording and drafting notes are original."},{"id":"ieee-functions","title":"IEEE C37.2-2022: power-system device function numbers","publisher":"IEEE","url":"https://ieeexplore.ieee.org/document/9984140","type":"standard","scope":"Device function numbers, acronyms and contact designations. The full publication may require access through IEEE.","checkedOn":"2026-10-13","reuse":"link-only","relevance":"Device-number and suffix convention. This page is not a reproduction of the full licensed standard."}]}