Protective Relay Reference

Data record std.ieee-c37-112.equation.operate-form

Verified 2026-10-24 Confidence: High

The trip equation of clause 3.2 of IEEE C37.112-2018 expresses operate time as the time dial multiplied by the sum of two terms: an inverse term, in which a curve constant is divided by the multiple of pickup raised to a curve exponent less unity, and a definite-time constant that represents the core saturation component of an induction relay.

ProvenanceIEEE C37.112-2018 supports data record std.ieee-c37-112.equation.operate-form, which is cited on the entry IEEE Standard for Inverse-Time Characteristics Equations for Overcurrent Relays.SOURCEIEEE C37.112-2018IEEE C37.112-2018Licensed standard, clause 3.2DATA RECORDstd.ieee-c37-112.equation.operate-formstd.ieee-c37-112.equatio..Verified 2026-10-24ENTRYIEEE Standard for Inverse-Time Characteristics Equations for Overcurrent RelaysIEEE Standard for Invers..No revisions
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StepItemDetail
SourceIEEE C37.112-2018Licensed standard, clause 3.2
Data recordstd.ieee-c37-112.equation.operate-formVerified 2026-10-24
EntryIEEE Standard for Inverse-Time Characteristics Equations for Overcurrent RelaysNo revisions
Subject
IEEE Standard for Inverse-Time Characteristics Equations for Overcurrent Relays (Standards)
Kind
Standard scope
Source
IEEE C37.112-2018, clause 3.2, IEEE Standard for Inverse-Time Characteristics Equations for Overcurrent Relays, IEEE.

History

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DateChange
2026-10-24created
2026-10-24review_status unreviewed -> software_reviewed

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"Data record std.ieee-c37-112.equation.operate-form." Protective Relay Reference. 2026-10-24. https://www.protectiverelayreference.com/data/std.ieee-c37-112.equation.operate-form/.