Voltage unbalance

Voltage unbalance meaning in Australian three-phase power-quality records.

  • Energy systems and power quality
  • Last checked 2026-07-13

Meaning in three-phase voltage records

Voltage unbalance describes how far measured three-phase voltages differ from their average or expected relationship. In Australian 230/400 V a.c., 50 Hz records it is usually a power-quality measurement value, not a diagnosis by itself.

The term should stay attached to the measurement point, voltage set, operating condition and threshold source. Mixing line-to-line and phase-to-neutral values without a clear basis can make the record hard to interpret.

Measurement set and threshold basis

Voltage-unbalance records need a consistent measurement set and a stated comparison basis. The calculator can process entered values, but the project still needs to say what threshold or source is being used.

Voltage unbalance record
Record contextKeep visibleWhy it matters
Measurement pointboard, equipment or supply locationShows where the voltage set was taken
Voltage setphase-to-phase or phase-to-neutral valuesPrevents mixed measurements from being compared
Review basisentered threshold, equipment note or DNSP contextSeparates the result from a universal limit

What unbalance does not diagnose

Voltage unbalance does not identify the cause on its own. Load distribution, supply conditions, equipment behaviour, measurement timing and instrument setup may all matter.

This glossary page does not set universal limits or diagnose faults. It defines the term so the calculator, chart and measurement table can be read consistently.

Using unbalance results

Use the voltage unbalance calculator for entered voltage measurements. Use the measurement table to record the point, operating condition and threshold basis before the result is used in a power-quality review.

Source and review

Check the terminology source, review timing and Australian application before carrying this term into a project record.

voltage unbalance source basis
ItemValue
SourceAUWiring voltage unbalance calculator wording, formula chart and power-quality measurement record table.
Source typeAustralian terminology
Derivation basisAUWiring Australian glossary term; no utility limits are reproduced as universal pass criteria.
Last checked2026-07-13
Review intervalAnnual terminology review or sooner if voltage-unbalance calculator wording changes.
Review triggerUpdate when voltage-unbalance calculator, chart or measurement table changes.
Version usedT41-2026-07-13
Australian applicationAustralia; Australian English power-quality terminology.

Term questions

Does voltage unbalance have one universal limit?

No. Review thresholds depend on equipment, utility and project context.

Does this term diagnose the cause?

No. Diagnosis needs investigation.