Transformer Testing Reference

IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers

Updated 2026-10-24

Edition timelineIEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers: 2015, 20212015201620172018201920202021IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating TransformersIEEE C57.12.90-2021IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers2015IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers2021
Edition timeline. Editions recorded for this standard from the publisher's catalog. The filled dot marks the edition listed as current.
Edition timeline: edition years from the publishers' catalogs; editions without a four-digit year are listed but not plotted.
StandardEditionKindCurrentRecord
IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers2015Revision ofstd.ieee-c57-12-90.revision-of
IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers2021Approvalstd.ieee-c57-12-90.approved

Data records

  • The IEEE SA Standards Board approved the 2021 edition of IEEE C57.12.90 on 2021-11-09. Value: 2021. Source: IEEE C57.12.90-2021, clause Front matter. Verified 2026-10-24. Record std.ieee-c57-12-90.approved
  • In IEEE C57.12.90-2021 the word liquid covers any insulating liquid used in a transformer, including mineral oil, natural ester, synthetic ester, silicone liquid and high molecular weight hydrocarbon. Source: IEEE C57.12.90-2021, clause 3. Verified 2026-10-24. Record std.ieee-c57-12-90.definition.liquid
  • IEEE C57.12.90-2021 is the designation of the document titled IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers. Value: IEEE C57.12.90-2021. Source: IEEE C57.12.90-2021, clause Front matter. Verified 2026-10-24. Record std.ieee-c57-12-90.designation
  • Clause 10.1.5.1 of IEEE C57.12.90-2021 orders the dielectric tests as lightning impulse, then switching impulse, then applied voltage, then induced voltage, with the induced-voltage test always last. Source: IEEE C57.12.90-2021, clause 10.1.5.1. Verified 2026-10-24. Record std.ieee-c57-12-90.dielectric-order
  • IEEE C57.12.90-2021 states test methods only; the requirements and tolerances it applies, such as the ratio tolerance referenced in clause 7.2 and the dielectric test levels referenced in clauses 10.1.2 and 10.5, are held by IEEE C57.12.00-2021. Source: IEEE C57.12.90-2021, clause 7.2, 10.1.2, 10.5. Verified 2026-10-24. Record std.ieee-c57-12-90.relationship.c57-12-00
  • IEEE C57.12.90-2021 is a revision of IEEE C57.12.90-2015. Value: 2015. Source: IEEE C57.12.90-2021, clause Front matter. Verified 2026-10-24. Record std.ieee-c57-12-90.revision-of
  • IEEE C57.12.90-2021 is a factory test code: it gives the methods for the tests that IEEE C57.12.00-2021 and related product standards specify for liquid-immersed distribution, power and regulating transformers, and clause 4.2 assumes that testing takes place at the manufacturer's works or at another facility that has been accepted for the purpose, except where a specification says otherwise. It does not apply to instrument transformers, step-voltage and induction voltage regulators, arc-furnace transformers, rectifier transformers, specialty transformers, grounding transformers or mine transformers. Source: IEEE C57.12.90-2021, clause 1.1, 1.2, 4.2. Verified 2026-10-24. Record std.ieee-c57-12-90.scope
  • The sponsor of IEEE C57.12.90-2021 is the Transformers Committee of the IEEE Power and Energy Society. Source: IEEE C57.12.90-2021, clause Front matter. Verified 2026-10-24. Record std.ieee-c57-12-90.sponsor
  • Annex B of IEEE C57.12.90-2021 is normative and gives the method for converting test results between the two standard power frequencies. Source: IEEE C57.12.90-2021, clause Annex B. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.annex-b
  • Clause 14 of IEEE C57.12.90-2021 covers calculated data: the reference temperature used for load losses, for regulation and for efficiency, the basis on which no-load and load losses are stated, the efficiency calculation, and the voltage regulation of a constant-voltage transformer. Source: IEEE C57.12.90-2021, clause 14. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.calculated-data
  • Clause 10 of IEEE C57.12.90-2021 covers the dielectric tests: general conditions and the field dielectric test clause in clause 10.1, impulse tests in clauses 10.2 through 10.4, low-frequency applied and induced voltage tests in clauses 10.5 through 10.8, partial discharge measurement in clause 10.9, insulation power factor in clause 10.10 and insulation resistance in clause 10.11. Source: IEEE C57.12.90-2021, clause 10. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.dielectric
  • Clause 9 of IEEE C57.12.90-2021 covers load losses and impedance voltage: definitions in clause 9.1, the factors that affect the measurement in clause 9.2, test preparation in clause 9.3, the phase-angle and temperature corrections and the impedance components in clause 9.4, and zero-sequence impedance in clause 9.5. Source: IEEE C57.12.90-2021, clause 9. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.load-loss
  • Clause 8 of IEEE C57.12.90-2021 covers no-load losses and excitation current: the components of no-load loss and the factors that affect it, the sine-wave basis and waveform correction, the temperature correction, the basis for expressing excitation current, and conversion between power frequencies. Source: IEEE C57.12.90-2021, clause 8. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.no-load-loss
  • Clause 6 of IEEE C57.12.90-2021 covers polarity and phase relation: Figures 2 and 3 define subtractive and additive polarity, the single-phase polarity methods are in clause 6.2 and the polyphase angular displacement and phase sequence methods are in clause 6.3. Source: IEEE C57.12.90-2021, clause 6. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.polarity
  • Clause 7 of IEEE C57.12.90-2021 covers the ratio test: the definition and test conditions in clause 7.1, a tolerance reference to IEEE C57.12.00-2021 in clause 7.2, and the voltmeter, comparison and ratio-meter methods in clause 7.3. Source: IEEE C57.12.90-2021, clause 7. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.ratio
  • Clause 5 of IEEE C57.12.90-2021 covers winding resistance measurement: determining the cold winding temperature, converting a measured resistance to a reference temperature, the measuring methods, and the connections and reporting for wye, delta and autotransformer windings. Source: IEEE C57.12.90-2021, clause 5. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.resistance
  • Clause 12 of IEEE C57.12.90-2021 covers the short-circuit test, grouping transformers into categories by kVA rating in Table 5 and setting in Table 6 of clause 12.5.4 the allowable change in per-phase leakage impedance after a short-circuit test series. Source: IEEE C57.12.90-2021, clause 12. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.short-circuit
  • Clause 11 of IEEE C57.12.90-2021 covers the temperature rise test and clause 13 covers audible sound, with the sound level report forms given as Figures 36 and 37. Source: IEEE C57.12.90-2021, clause 11, 13. Verified 2026-10-24. Record std.ieee-c57-12-90.structure.temperature-rise-and-sound
  • A note in clause 4.3 of IEEE C57.12.90-2021 recommends that the dielectric tests come after the tests made at reduced voltage: winding resistance, polarity with phase relation, turns ratio, no-load loss with excitation current, impedance with load loss, and temperature rise. Source: IEEE C57.12.90-2021, clause 4.3. Verified 2026-10-24. Record std.ieee-c57-12-90.test-order
  • Clauses 4.1 and 4.2 of IEEE C57.12.90-2021 take the test categories routine, design, conformance and other from the IEEE transformer terminology standard and leave the assignment of tests to each category to Table 17 of IEEE C57.12.00-2021. Source: IEEE C57.12.90-2021, clause 4.1, 4.2. Verified 2026-10-24. Record std.ieee-c57-12-90.test-types
  • The licensed copy of IEEE C57.12.90-2021 carries the full title IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers. Value: IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers. Source: IEEE C57.12.90-2021, clause Front matter. Verified 2026-10-24. Record std.ieee-c57-12-90.title

Sources

  • IEEE C57.12.90-2021, Test Code for Liquid-Immersed Distribution, Power and Regulating Transformers, 2021 edition, IEEE. Cited: clause Front matter; clause 3; clause 10.1.5.1; clause 7.2, 10.1.2, 10.5; clause 1.1, 1.2, 4.2; clause Annex B; clause 14; clause 10; clause 9; clause 8; clause 6; clause 7; clause 5; clause 12; clause 11, 13; clause 4.3; clause 4.1, 4.2. Held as: Purchased single-user copy.

Obtaining the documents

Changelog (47 entries)
DateRevisionChange
2026-10-24created (std.ieee-c57-12-90.approved)
2026-10-24revised (std.ieee-c57-12-90.approved)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.approved)
2026-10-24created (std.ieee-c57-12-90.definition.liquid)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.definition.liquid)
2026-10-24created (std.ieee-c57-12-90.designation)
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2026-10-24created (std.ieee-c57-12-90.dielectric-order)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.dielectric-order)
2026-10-24created (std.ieee-c57-12-90.relationship.c57-12-00)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.relationship.c57-12-00)
2026-10-24created (std.ieee-c57-12-90.revision-of)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.revision-of)
2026-10-24created (std.ieee-c57-12-90.scope)
2026-10-24revised (std.ieee-c57-12-90.scope)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.scope)
2026-10-24created (std.ieee-c57-12-90.sponsor)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.sponsor)
2026-10-24created (std.ieee-c57-12-90.structure.annex-b)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.annex-b)
2026-10-24created (std.ieee-c57-12-90.structure.calculated-data)
2026-10-24revised (std.ieee-c57-12-90.structure.calculated-data)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.calculated-data)
2026-10-24created (std.ieee-c57-12-90.structure.dielectric)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.dielectric)
2026-10-24created (std.ieee-c57-12-90.structure.load-loss)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.load-loss)
2026-10-24created (std.ieee-c57-12-90.structure.no-load-loss)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.no-load-loss)
2026-10-24created (std.ieee-c57-12-90.structure.polarity)
2026-10-24revised (std.ieee-c57-12-90.structure.polarity)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.polarity)
2026-10-24created (std.ieee-c57-12-90.structure.ratio)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.ratio)
2026-10-24created (std.ieee-c57-12-90.structure.resistance)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.resistance)
2026-10-24created (std.ieee-c57-12-90.structure.short-circuit)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.short-circuit)
2026-10-24created (std.ieee-c57-12-90.structure.temperature-rise-and-sound)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.structure.temperature-rise-and-sound)
2026-10-24created (std.ieee-c57-12-90.test-order)
2026-10-24revised (std.ieee-c57-12-90.test-order)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.test-order)
2026-10-24created (std.ieee-c57-12-90.test-types)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.test-types)
2026-10-24created (std.ieee-c57-12-90.title)
2026-10-24review_status unreviewed -> software_reviewed (std.ieee-c57-12-90.title)

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Cite the governing standard for the fact itself; cite this page as the finding aid.

"IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers." Transformer Testing Reference. 2026-10-24. https://www.transformertestingreference.com/standards/ieee-c57-12-90/.