{"schemaVersion":1,"slug":"27t-low-voltage-ride-through-supervision","name":"Low-voltage ride-through supervision","kind":"function","abbreviation":"27T","aliases":["LVRT","voltage ride through","27RT","ANSI 27T","IEEE 27T"],"category":"measurement-protection","drawingTypes":["SLD","Schematic"],"referenceFamilies":["IEEE / ANSI","Manufacturer"],"summary":"Supervises a voltage-time ride-through criterion used in a generator or interconnection application.","description":["Supervises a voltage-time ride-through criterion used in a generator or interconnection application.","The drafting record should connect this function to the measured terminal voltage and applicable voltage-time characteristic, then trace the ride-through function output and interconnection protection logic. 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 (Eaton ETR family). Suffixes are not universal equivalences across products, and this reference supplies neither a protection setting nor certification of the selected scheme."],"readingNotes":["Identify the measured terminal voltage and applicable voltage-time characteristic.","Trace the ride-through function output and interconnection protection logic."],"drawingChecklist":["Label the measured terminal voltage and applicable voltage-time characteristic.","Cross-reference the ride-through function output and interconnection protection logic.","Retain the complete suffix, selected device tag and manufacturer manual revision."],"distinction":"A ride-through envelope is not a fixed undervoltage pickup; the reference does not establish compliance with a connection requirement.","facts":[{"label":"Function designation","value":"27T"},{"label":"Base function","value":"27 — Undervoltage"},{"label":"Published mapping","value":"Eaton ETR family"},{"label":"Suffix scope","value":"Application or manufacturer specific; check the complete drawing legend and selected device manual."}],"references":[{"sourceId":"pub-function-eaton-transformer","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":["27-undervoltage","voltage-transformer"],"artwork":"pub-function-box","publishedOn":"2026-10-13","updatedOn":"2026-10-13","provenance":"independent-public-research","url":"https://eloragrid.ai/protection-functions/27t-low-voltage-ride-through-supervision","illustration":{"url":"https://eloragrid.ai/library/illustrations/27t-low-voltage-ride-through-supervision.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-eaton-transformer","title":"ETR-4000 and ETR-5000 transformer protection function tables","publisher":"Eaton","url":"https://www.eaton.com/us/en-us/catalog/electrical-circuit-protection/transformer-relays.html","type":"manufacturer","scope":"Public transformer-relay mappings including restrained/unrestrained differential, restricted ground differential, main and auxiliary voltage inputs, and measured/calculated earth-current inputs.","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."}]}