[time-nuts] Re: My AC measurement project & question

[Chris Hastreiter]

I work in the distribution grid protection equipment business, and our
products include measurement capability up to the 16th harmonic for both
the voltage and current measurements made on the line.  For classic grid
protection primarily the fundamental and second harmonic are used, but the
higher harmonics are being used more now for high impedance arc fault
detection (think California wildfires) and understanding the operating
behavior of distributed generation resources.

The frequency response characteristics of all the related transformers
certainly aren't linear, but most of these algorithms are looking for the
presence of higher harmonic content rather than trying to measure specific
magnitude values for them.  So yes, higher frequency content can certainly
be on the grid at least at the distribution level, but in a residential
setting much of the harmonic content present will be caused by the
conducted emissions from local devices through their power supplies.

Chris

On Mon, Jan 24, 2022 at 12:04 AM Hal Murray <halmurray at sonic.net> wrote:

>
> kb8tq at n1k.org said:
> > If the transformer works well up to 600Hz, isn???t that high enough to
> capture
> > anything that actually is grid related (as opposed to local to your home
> /
> > neighborhood )?
>
> What's the frequency response of the transformer
>   on the pole outside my house
>   at the nearby substation
>   at a big substation
>
> I remember that back in the days of tubes where audio amplifiers had a
> transformer to drive a speaker, there was a lot of iron in the
> transformer.  I
> think that was for the low frequency.  I don't remember anything about
> high
> frequencies.  Was that because there wasn't a problem or I wasn't paying
> attention?
>
> What is the frequency response of a wall wart size transformer?
>
> ---------
>
> Is the frequency response of transmission lines interesting?
>
> --
> These are my opinions.  I hate spam.
>
>
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