Harmonic Solution Idea
Harmonic Solution Idea
(OP)
We are having problems in the field with drive trips, fuses blowing,etc caused by high level 5th order harmonics on our lines. With over 1000 6 pulse vfds installed and little or no filtering on the drives, the voltage distortion is really bad.
The thought is to have half of the sites pole top power transformers rewired from delta-delta to delta-wye to create a sort of area wide 30 degree phase shift on 50% of the distribution load and hopefully cancel out that troublesome 5th.
Was wondering if anyone had tried this before and seen it work in practice.
The thought is to have half of the sites pole top power transformers rewired from delta-delta to delta-wye to create a sort of area wide 30 degree phase shift on 50% of the distribution load and hopefully cancel out that troublesome 5th.
Was wondering if anyone had tried this before and seen it work in practice.






RE: Harmonic Solution Idea
The 30 degrees phase shift will not do much to improve the LV side situation, but it will definitely be a good thing to do for 4160 V distorsion.
So, if you have the problem on the 4160 V side - just do it. But if problems are on the LV side, find other solution.
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: Harmonic Solution Idea
Any new drives added automatically are subjected to the harmonics.
RE: Harmonic Solution Idea
It is being done with larger drives by using double secondary windings with 30 degrees phase difference (one Y and one D winding). Sometimes even with four 15 degrees shifted windings.
As I said, just do it!
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Harmonic Solution Idea
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Harmonic Solution Idea
RE: Harmonic Solution Idea
A previous discussions:
Harmonics and VFDs
thread237-205555: Harmonics and VFDs
Alternately you may be able to do some phase shifting on parts of the 12.5KV lines.
Bill
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"Why not the best?"
Jimmy Carter
RE: Harmonic Solution Idea
Threadful, I would say
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.