IEEE 1584 · Engineering

Harmonic Study & Analysis - Carelabz Romania

Carelabs delivers harmonic study and analysis for industrial and commercial facilities across Romania, measuring total harmonic distortion with a harmonics analyser and modelling system impedance versus frequency to identify resonance risk. Where levels exceed the limits set in SR EN 50160, we recommend mitigation — harmonic filters, relocated power-factor correction capacitance, or higher-pulse-number rectifiers — and verify compliance with Normativ I7-2011.

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The conductor nobody sized for this

In a three-phase four-wire installation the third harmonic and its odd multiples do not cancel in the neutral. They add. The neutral can end up carrying more current than any phase.

What We Deliver

Neutral current measured, not assumed

Neutral current is recorded directly rather than calculated from phase imbalance. Where single-phase non-linear load is significant, the measured value is frequently well above what any balance calculation would predict.

WHY IT MATTERS

A fire risk before it is an efficiency problem

An overloaded neutral has no protection of its own in most installations. It carries current the designer did not anticipate, in a conductor that may be undersized, with nothing to operate when it overheats.

Neutral current measured directly at the board rather than inferred from phase readings, since triplen summation is invisible to a balance calculation.
Triplen harmonic content separated from the total, because it is the specific component that accumulates in the neutral.
Neutral conductor size compared against measured current, including installations where a reduced neutral was originally permitted.
Thermographic survey of neutral terminations where loading is significant, as heating at a joint precedes failure by a long period.
Load distribution reviewed, since redistributing single-phase non-linear load across phases does not reduce triplen current in the neutral.

DELIVERABLES

What you receive

Issued against I7-2011 and SR HD 60364, with the measurement basis stated.

1Measured neutral current per board alongside phase currents
2Triplen harmonic content separated from total distortion
3Neutral conductor adequacy assessment against measured rather than assumed loading
4Thermographic findings on neutral terminations where loading is significant
5Mitigation options including zig-zag transformers, harmonic filters and conductor upsizing

Reach Out

How the study runs

Identify the load type

We establish where single-phase non-linear load concentrates, since that is what produces the triplen content that accumulates in the neutral.

Measure phase and neutral together

Currents are recorded on all four conductors across a representative period, which is what reveals a neutral carrying more than its phases.

Separate the spectrum

Triplen orders are distinguished from the rest, because only those sum in the neutral and only their proportion matters for this question.

Assess the conductor

Measured neutral current is compared against the installed conductor's rating, taking the installation method and grouping into account.

Survey the terminations

Thermographic imaging under load identifies neutral joints already heating, which is where the immediate risk sits rather than in the cable run.

Report and options

Findings are issued with mitigation options, distinguishing those that reduce triplen current from those that simply carry it more safely.

Frequently asked questions

Yes. Third harmonic current in each phase arrives in the neutral in phase with the others and sums rather than cancelling. With heavy single-phase electronic load, measured neutral current of well over a hundred percent of phase current is entirely possible, in a conductor that may have been sized smaller deliberately.

No, and this is the common misconception. Balancing addresses fundamental-frequency imbalance, which does cancel in the neutral. Triplen harmonics sum regardless of how evenly the load is distributed, so a perfectly balanced installation with heavy electronic load still has an overloaded neutral.

Usually not. Overcurrent protection monitors the phases, so a neutral carrying excessive current has nothing to operate on its behalf. That is precisely why the condition progresses to overheating and, in the worst case, fire, without any protective device indicating a problem.

Either reduce the triplen current or carry it safely. Zig-zag transformers and tuned filters reduce it; upsizing the neutral or splitting the load across additional circuits carries it. Which is appropriate depends on the installation, and the study establishes the measured current the decision must be sized against.

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