Mysterious Power Line Super Gremlins

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  • george daniel
    george daniel Posts: 12,096
    edited March 2009
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    Guy's,, that was,, seriously,, a most interesting read.:)
    JC approves....he told me so. (F-1 nut)
  • DarqueKnight
    DarqueKnight Posts: 6,765
    edited March 2009
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    I-SIG wrote: »
    ....are you gonna add the transformer??? :confused:

    No.
    If I planned to be in my current house for a long time, and if the amount of noise reduction would be in the range of 5 to 10 times, I wouldn't hesitate to have the dedicated transformer installed.

    I will definitely consider a dedicated transformer or a commercial grade AC regenerator (or both :)) for my next house.



    ....
    Proud and loyal citizen of the Digital Domain and Solid State Country!
  • Townshend
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    Apologizes for bumping an old thread although there isn't a ton of information nor dialog relating to high harmonic distortion in residential environments.

    Ultimately, who did you find at the utility to speak with (person or department) that had the most knowledge?

    Also what equipment/software did you utilize to measure the dB and produce sine wave? Or if anyone has any suggestions please share.

    While I haven't been able to measure at the PCC I have been experiencing significant THDv. The lowest I've seen is 9.1% with it hitting 11.4% at the outlet. Even measuring at the legs coming into the breaker panel prior to the master switch I measured 11.1%. This morning I measured the following:

    THDv 9.8%:

    h01 - 100%
    h02 - 0.0%
    h03 - 9.7%
    h04 - 0.0%
    h05 - 1.8%
    h06 - 0.0%
    h07 - 0.4%
    h08-25 - 0.0%

    I have not been able to measure at the PCC. My challenges thus far have been finding someone who actually has knowledge in harmonics both at the utility as well as just in general. Audio forums seem to be where I see the most discussion!
  • DarqueKnight
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    Townshend wrote: »
    Apologizes for bumping an old thread although there isn't a ton of information nor dialog relating to high harmonic distortion in residential environments.

    Ultimately, who did you find at the utility to speak with (person or department) that had the most knowledge?

    Also what equipment/software did you utilize to measure the dB and produce sine wave? Or if anyone has any suggestions please share.

    No worries about bumping an old thread. We do it all the time here.

    I spoke to a supervisor in my utilities facilities planning department. Ask your utility company which department is responsible for power quality.

    I used a Tektronix TDS 2012 oscilloscope. The oscilloscope showed the sine wave (time domain) and it also has a Fast Fourier Transform (FFT) function that shows the power signal in frequency domain. The oscilloscope's FFT function has dB on the vertical axis and hertz on the horizontal axis.

    I also have use AC regenerators that show the before and after sine wave (after it has been cleaned up by the regenerator) and before and after THD.

    See this thread for reference, particularly the third paragraph after figure 7:

    https://forum.polkaudio.com/discussion/71333/studies-on-residential-power-line-noise-part-1


    Proud and loyal citizen of the Digital Domain and Solid State Country!
  • Townshend
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    Thank you! The power quality tip is one I'll try with them tomorrow.

    Would an AC regenerator be the solution if I can't determine the root cause? The challenge I'm having isn't in my audio equipment, rather a UPS that is alternating between line and battery power and I am nearly certain it is due to higher than normal harmonics.

    I've also come across passive/active harmonic filters and line reactors but not sure if those will accomplish what I am looking for.
  • treitz3
    treitz3 Posts: 18,470
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    One thing to keep in mind....have patience, and be the squeaky wheel. (if you will)

    Power companies are not on the same timeline, nor the same care factor as we are. I know this from direct experience and the issue *may* not be at a local transformer. The root cause of an issue may be miles down the road and this takes time.

    Power companies just LOVE to deny, deny, deny anything that may be on their end. It is up to us to prove it to them. Food for thought.

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
  • DarqueKnight
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    Townshend wrote: »
    The challenge I'm having isn't in my audio equipment, rather a UPS that is alternating between line and battery power and I am nearly certain it is due to higher than normal harmonics.

    I've also come across passive/active harmonic filters and line reactors but not sure if those will accomplish what I am looking for.

    The manufacturer of your UPS should know what is causing your problem. Have you contacted their technical support?

    Proud and loyal citizen of the Digital Domain and Solid State Country!
  • Townshend
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    treitz3 wrote: »
    One thing to keep in mind....have patience, and be the squeaky wheel. (if you will)

    Power companies are not on the same timeline, nor the same care factor as we are. I know this from direct experience and the issue *may* not be at a local transformer. The root cause of an issue may be miles down the road and this takes time.

    Power companies just LOVE to deny, deny, deny anything that may be on their end. It is up to us to prove it to them. Food for thought.

    Tom

    A lesson I have been learning slowly but surely over the past 5-6 months!

    You could very well be right that the issue is further upstream. I noticed high THDv% at a house I measured a few miles away that there's no way is on the same transformer.

    One commonality on the residential houses I've tested with is that their initial construction is older. Both neighborhoods were originally developed in the 1960s-1970s.
  • Townshend
    Townshend Posts: 4
    edited November 2022
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    Townshend wrote: »
    The challenge I'm having isn't in my audio equipment, rather a UPS that is alternating between line and battery power and I am nearly certain it is due to higher than normal harmonics.

    I've also come across passive/active harmonic filters and line reactors but not sure if those will accomplish what I am looking for.

    The manufacturer of your UPS should know what is causing your problem. Have you contacted their technical support?

    Yes, thus far I have not been successful at getting a cause determined. Any L1/L2 techs I've called in the issue on have simply sent a replacement UPS under warranty. Now that I have some data points on harmonics and on the 3rd UPS it has been escalated up the chain. They have input voltage range defined in documentation but nothing on harmonics or if there's any other metrics that could cause to go off line power. They do have output harmonics though documented, just not input.

    At this point, it's an educated guess and process of elimination that harmonic distortion is the cause of the alternation between battery and line. At three commercial places with low distortion (<3%), no issues. At two residential places with 9%+ distortion, issues. Even here when THDv is at 8.9% on the one occasion I did see it in the 8s it was a little more stable.

    I should also note I have monitored voltage and frequency. Nothing out of the ordinary there, voltages and freq were measured both on the logs of the UPS and a Fluke 179. Voltage ranged between 122-125V and frequency 59.89-59.99Hz.
  • treitz3
    treitz3 Posts: 18,470
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    Have you had incoming voltage fluctuations monitored by the power company at the incoming x-nsfrmr?

    I would advise having them do this over a period of 2 weeks and have them RECORD the results.

    Tom
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~