Total Harmonic Distortion (THD) on neutral voltage and current

Yoses_Ginting · Dec 19, 2023

Hi All,

I'm doing internship in fluor factory project. During commissioning, 4 of their machine were failed due to harmonic.
Machine harmonic protection controller card was damage. Many of their machine is actually single phase.
Based on attached power quality measurement, found that THD on neutral current and voltage is very high.
THD current is more than 8%.
Could you advise me what is solution for this issue?

Thanks.

Gr8blu · Dec 21, 2023

1. Separate harmonic sources from sensitive equipment - if necessary, use completely separate bus configuration.
2. Replace sensitive equipment with not-so-sensitive equipment. (Note that it is unlikely that anything capable of handling more than 8% THD will be commercially available.)
3. Install the proper harmonic filters at the critical points in the distribution system.

If the neutral is showing high THD (voltage or current), chances are pretty good that the main phases also have high THD. It is not uncommon for one phase to have a different THD than the other two, or from the neutral. How much depends on the loads on that phase that produce harmonics (such as fluorescent and LED lighting, power converters, computers and servers, arcing devices, etc.)

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Total Harmonic Distortion (THD) on neutral voltage and current

Yoses_Ginting

Electrical

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Gr8blu

Electrical

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