Harmonics Problem

[JAMartinezB]

Hi, I am having problems with high measurements of THD% current (27%) and voltage (8%). But I'm not sure whether the source of these high THD is my load or the network.

I wonder how I could determine when a harmonic problem in the customer side is produced mainly by its loads or by the others load in the network.

Regards.

 

[rbulsara]

What is your network? Where are you monitoring this? What type of loads are the in your facilities.

Those numbers you indicated are not particularly high where there are a lot of computers.

To determine harmonics in individual load circuits, you need to measure them individually.

More importantly are you having an issue or you just happen to measure it and now started worrying?

 

[LionelHutz]

That sounds typical of a site with a mix of harmonic producing equipment - maybe a number of VFD's in the system?

Do you have capacitor banks in your system? Typically, you would see voltage harmonics from the "outside" world and capacitors can be excited by the voltage harmonics and draw extra current at the different harmonic frequencies.

 

[ghostbuster7]

If possible measure the voltage T.H.D. with all customer loads turned off.This will give you an indication customer/network side.

 

[7anoter4]

I don't know if the IEEE paper is as useful as they declare but if you don't mind the cost you can try this link:

http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel3/61/10569/00489362.pdf?arnumber=489362

"On separating customer and supply side harmonic contributions"