Neutral harmonic current calculator
Estimate neutral triplen harmonic current from entered phase harmonic current records for Australian power-quality review.
I_N_triplen = I_A_triplen + I_B_triplen + I_C_triplen- Use odd triplen harmonic orders such as 3, 9 or 15.
- Phase currents must be RMS values from one measurement record.
- The threshold is entered by the user from project, report, equipment or engineering criteria.
| Variable | Meaning | Unit | Use |
|---|---|---|---|
| I_A_triplen | Phase A triplen harmonic current | A | Entered RMS current for the selected triplen harmonic on Phase A. |
| I_B_triplen | Phase B triplen harmonic current | A | Entered RMS current for the selected triplen harmonic on Phase B. |
| I_C_triplen | Phase C triplen harmonic current | A | Entered RMS current for the selected triplen harmonic on Phase C. |
| I_N_triplen | Neutral triplen harmonic current | A | Arithmetic sum of the entered triplen harmonic phase currents. |
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Neutral harmonic current calculator technical guide
Estimate neutral triplen harmonic current from entered phase harmonic current records for Australian power-quality review.
Use this calculator when a power-quality record lists triplen harmonic current by phase and you need a neutral-current worksheet. It keeps the harmonic order, three phase rows and threshold basis visible before anyone interprets the result.
This page is separate from the ordinary neutral current calculator. Linear phase-current imbalance and triplen harmonic neutral current use different input records and should not be collapsed into one result.
Triplen Harmonic Record
| Field | Why it matters | Review note |
|---|---|---|
| Harmonic order | Restricts the worksheet to odd triplen orders. | Use 3, 9 or 15 from the measurement record. |
| Phase harmonic currents | Carries the RMS row for each phase. | Use rows from one measurement window. |
| Review threshold | Gives the comparison value. | Keep the source visible. |
| Threshold basis | Explains the comparison value. | Avoid a hidden equipment-rating impression. |
The calculator adds the entered triplen phase currents arithmetically because these components can add in the neutral. That arithmetic is a record summary, not a source diagnosis.
Result Interpretation
| Output | Meaning | Practical reading |
|---|---|---|
| Neutral harmonic current | Sum of the entered triplen phase rows. | Main worksheet result. |
| Phase spread | Difference between the largest and smallest phase harmonic current. | Shows how uneven the record rows are. |
| Dominant phase | Largest entered phase row. | Points to the largest contributor in this simple record. |
| Threshold basis | Source of the entered review value. | Keeps interpretation tied to the record source. |
If the result is above the entered threshold, review the analyser record, neutral rating, equipment context and threshold source before using the value. If it is below the entered threshold, keep it as one record only; another loading state may produce different harmonic currents.
Boundary With Related Calculators
| Question | Correct owner | Input basis |
|---|---|---|
| What neutral current follows from triplen harmonic phase rows? | Neutral harmonic current calculator | Third, ninth or fifteenth harmonic current by phase. |
| What TDD follows from current harmonics and demand current? | Harmonic current TDD calculator | Harmonic current RMS rows and demand current. |
| What neutral current follows from phase-current imbalance? | Neutral current calculator | Entered phase currents for linear-load arithmetic. |
| What fields belong in a PQ record? | Power-quality measurement record table | Instrument, location and measurement context. |
Worked Records
| Situation | Inputs | Result pattern | Interpretation |
|---|---|---|---|
| Third-harmonic neutral record | 8 A, 7.5 A and 8.5 A phase rows | 24 A neutral harmonic current | Above the entered 20 A review value. |
| Higher review value | Same phase rows, 30 A review value | 24 A neutral harmonic current | Below the entered threshold, with same measurement context. |
| Ninth-harmonic measurement note | 2.2 A, 2 A and 2.4 A phase rows | 6.6 A neutral harmonic current | Lower record with Phase C as largest row. |
Stop Points
- The harmonic order is not an odd triplen order.
- The phase rows come from different measurement windows.
- The values are percentages rather than RMS current values.
- The threshold has no stated project, equipment, report or engineering basis.
- The result is being used as a source diagnosis without wider measurement review.
Third-harmonic neutral record
A power-quality note gives third-harmonic current values for each phase on one switchboard record.
- Reference
- PQ-NEUTRAL-H3-01
- Harmonic order
- 3
- Phase A
- 8 A
- Phase B
- 7.5 A
- Phase C
- 8.5 A
- Neutral harmonic current24 A
- Phase spread1 A
- Dominant phasePhase C
Arithmetic sum of the entered triplen harmonic phase currents.
The summed triplen current is above the entered threshold, so the measurement and neutral-current basis should be reviewed.
- Phase harmonic currents are RMS values from one record.
- The harmonic order is triplen.
- The threshold source remains visible.
Higher neutral-current review value
The same third-harmonic record is compared with a higher user-entered review value.
- Reference
- PQ-NEUTRAL-H3-HIGH
- Harmonic order
- 3
- Phase A
- 8 A
- Phase B
- 7.5 A
- Phase C
- 8.5 A
- Neutral harmonic current24 A
- Phase spread1 A
- Dominant phasePhase C
Arithmetic sum of the entered triplen harmonic phase currents.
The current record stays below the entered threshold while still needing the same measurement context.
- The phase values are unchanged.
- The review value changed.
- No equipment rating is embedded.
Ninth-harmonic measurement note
A separate analyser row gives ninth-harmonic current values with a lower summed neutral current.
- Reference
- PQ-NEUTRAL-H9-01
- Harmonic order
- 9
- Phase A
- 2.2 A
- Phase B
- 2 A
- Phase C
- 2.4 A
- Neutral harmonic current6.6 A
- Phase spread0.4 A
- Dominant phasePhase C
Arithmetic sum of the entered triplen harmonic phase currents.
The summed ninth-harmonic current is below the entered review value, with Phase C as the largest row.
- The order is an odd triplen harmonic.
- Rows belong to one measurement window.
- Neutral heating assessment remains external.