Total harmonic distortion (THD)
Updated 2026-10-27
Data records
- IEEE 1159-2019 lists total harmonic distortion among the harmonic parameters a power quality monitor computes from each measurement window, and names IEEE 519 and IEC 61000-4-7 as the standards that govern those harmonic parameters.
- Total harmonic distortion in IEEE 519-2022 is the rms of the harmonic content of a voltage or current, excluding interharmonics and taken up to the harmonic order stated in the definition, divided by the fundamental and expressed as a percent.
- Total harmonic distortion is a dimensionless ratio expressed as a percent of the fundamental component, so it carries no unit of its own.
- In IEEE 519-2022 total harmonic distortion of the voltage is the second column of Table 1, the voltage distortion limit table, and is compared with the limits through the daily and weekly percentile statistics of clause 4.4.
- The term is written Total harmonic distortion (THD). Value: Total harmonic distortion (THD).
Sources
- Electrical Testing Reference editorial taxonomy, Electrical Testing Reference editorial taxonomy of test methods, 2026-10 edition, Electrical Testing Reference. Held as: Own observation.
- IEEE 1159-2019, Recommended Practice for Monitoring Electric Power Quality, 2019 edition, IEEE. Cited: clause 6.5.3.2. Held as: Purchased single-user copy. Publisher page for IEEE 1159-2019Publisher information page
- IEEE 519-2022, Harmonic Control in Electric Power Systems, 2022 edition, IEEE. Cited: clause 3.1; clause 5.1. Held as: Purchased single-user copy. Publisher page for IEEE 519-2022Publisher information page
Obtaining the documents
- IEEE 1159-2019: available from the publisher
- IEEE 519-2022: available from the publisher
Changelog (5 entries)
| Date | Revision | Change |
|---|---|---|
| 2026-10-27 | created (qty.total-harmonic-distortion.ieee1159.measurement) | |
| 2026-10-27 | created (qty.total-harmonic-distortion.ieee519.definition) | |
| 2026-10-27 | created (qty.total-harmonic-distortion.ieee519.unit) | |
| 2026-10-27 | created (qty.total-harmonic-distortion.ieee519.use) | |
| 2026-10-27 | created (qty.total-harmonic-distortion.title) |
Cite this page
Cite the governing standard for the fact itself; cite this page as the finding aid.
"Total harmonic distortion (THD)." Power Quality Reference. 2026-10-27. https://www.powerqualityreference.com/quantities/total-harmonic-distortion/.
Power Quality Reference, Total harmonic distortion (THD) (Oct. 27, 2026), https://www.powerqualityreference.com/quantities/total-harmonic-distortion/.
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title = {Total harmonic distortion (THD)},
howpublished = {\url{https://www.powerqualityreference.com/quantities/total-harmonic-distortion/}},
organization = {Power Quality Reference},
publisher = {Power Quality Reference},
year = {2026},
note = {last substantive change 2026-10-27}
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