Zero and Even Order Harmonics

Y

Thread Starter

Yudie Soeryadharma

Hi Everyone

I just measured cable factory for their power quality. The main transformer capacity 1600KVA and the load only 750KVA.

But i wonder why the voltage waveform is sinus shape but it was distorted/notched all around the waveform?
i check THDv = 4.9, THDi = 19% PF = 0.84

I went down to the sub panel (annealing machine and pump), the same result with the voltage waveform...THDv < 5% but the waveform is distorted.

1. Anyone can help to explain this issue?

2. I found the zero order, 2, 3, 4 order harmonics on the sub panel. is it because the distorted voltage?

Thank you everyone
Yudie
[email protected]
 
R
I have found that any form of solid state switching plays havoc with the sinewave. It doesn't even have to be in the same building.
 
Waveform is unlimited, therefore distortion is expansion, also known as PO - progressive order;

4% of power on 750KVA of load, even in the capacity of 1600KVA, leaves you with over 40% of potentiality. Once you reach the half-line of the sinus knowing it will become multiple-notched-helices proceed to keep the main transformer (ie. the cable's body) plugged and leave the sub panel whole.

Your check is good, just make sure to take it easy on the numbers, you wanna have power after all, after the stasis.

Just doin't,
Saywhat
 
C

Curt Wuollet

The days of nice linear and resistive loads has passed. Practically everything with electronics in it (which is about everything) draws current for only part of the waveform, often in very narrow conduction angles. A whole building full of electronic ballasts, VFDs, SCR controls and the like can alter the voltage at waveform at the service and the current waveform is almost certainly not a pure sinusoid. We didn't even talk about harmonic distortion with a pair of 9MW induction iron melters in the plant. A lot of electricians are learning a lot more about harmonics than they really wanted to know.

Regards
cww
 
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