Harmonic THD workflow
How to prepare fundamental and harmonic RMS measurement records before using the Australian harmonic THD calculator.
THD record purpose
Harmonic THD calculation starts with one measurement record: a fundamental RMS magnitude and harmonic RMS magnitudes from the same voltage or current record.
The calculator shows distortion magnitude. It does not identify the source of distortion.
Workflow
- Confirm whether the record is voltage harmonics or current harmonics.
- Record the fundamental RMS magnitude from the analyser or report.
- Enter harmonic RMS magnitudes from the same record.
- Record threshold source and measurement location.
- Carry the result into equipment, DNSP or project review only with the measurement context attached.
Record table
| Field | Record | Review concern |
|---|---|---|
| Record type | Voltage or current harmonics | Do not mix record types |
| Fundamental RMS | H1 value from same record | Drives THD percentage |
| Harmonic rows | RMS magnitudes from analyser | Must share the same measurement set |
| Threshold basis | Project or equipment source | Not supplied by the page |
| Dominant harmonic | Largest entered harmonic row | Helps route follow-up review |
Boundaries
- Do not use THD alone to identify the source.
- Do not mix voltage and current values.
- Do not combine readings from different times.
- Do not hide analyser setup or threshold source.