Fault event with harmonics

[cranky108]

Has any one seen a 3 phase fault event with 2nd and 4th harmonics on each phase?

My first impression was an inrush, but the the event lasted to long for that. The distribution feeder has both over head and under ground sections, so there could have been some higher frequency ringing.
And maybe this could be because the substation is lightly loaded at this time.

 

[Skogsgurra]

That may be because your recording device doesn't have adequate anti-alias filtering.

Then, high-frequency components that are above the Nyquist frequency get folded back into the (usually) 50/60 to 2500/3000 Hz band and represented as both odd and even harmonics. One particular device, let's call it PPxxxx, has done that to me on many occasions. I have got used to it and am always aware of that possibility.

Gunnar Englund

http://www.gke.org

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