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Thread: Harmonics in Green Buildings

  1. #1
    T.M.Haja Sahib Guest

    Harmonics in Green Buildings

    It is stated that in green buildings the harmonic producing electronic loads should not exceed 10% of total load to limit the electronic noise of harmonics. I do not know this is achievable. Your input please.

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    Quote Originally Posted by T.M.Haja Sahib View Post
    It is stated that in green buildings the harmonic producing electronic loads should not exceed 10% of total load to limit the electronic noise of harmonics. I do not know this is achievable. Your input please.
    Isn't anything possible if you throw enough money at it?
    Slightly more seriously, yes, I think it's achievable.

  3. #3
    T.M.Haja Sahib Guest
    Quote Originally Posted by Besoeker View Post
    Isn't anything possible if you throw enough money at it?
    Slightly more seriously, yes, I think it's achievable.
    I simply adopted your own country philosopher Sir Bertrand Russeli's statement that some American millionaires think themselves as gods, implying that with their huge amount of money nothing is difficult to them.
    More seriously, I am wondering. with high proliferation of single phase harmonic producing electronic loads in any building, how it could be possible to contain them within 10%.

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    US standards require power factor of .9 for commercial LEDs

    http://www.ecnmag.com/products/2011/...s-led-lighting

  5. #5
    T.M.Haja Sahib Guest
    Quote Originally Posted by fmtjfw View Post
    US standards require power factor of .9 for commercial LEDs

    http://www.ecnmag.com/products/2011/...s-led-lighting
    Thanks, fmtjfw. Providing electronic loads with active power factor correction is the way to limit raw harmonic producing electronic loads to within 10%.
    Last edited by T.M.Haja Sahib; 07-18-12 at 08:02 AM. Reason: to change real by raw

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    Quote Originally Posted by T.M.Haja Sahib View Post
    I simply adopted your own country philosopher Sir Bertrand Russeli's statement that some American millionaires think themselves as gods, implying that with their huge amount of money nothing is difficult to them.
    More seriously, I am wondering. with high proliferation of single phase harmonic producing electronic loads in any building, how it could be possible to contain them within 10%.
    I would think it more important to use mitigating measures to prevent the harmonics from polluting the supply network to the building rather than puting a limit on harmonic producing load within it.
    However, there are ways and means to reduce the harmonics produced by any piece of kit. You mentioned a sine wave input SMPS in another thread. Use that technique in all electronic gizmos - job done. More expensive but done.
    An alternative approach is to run things like computers from a UPS (we do our servers that way) with a sine wave input.
    Any drives van be active front end.
    Anything can have a passive harmonic filter included at its input.

    And, I ought to ask you what the 10% refers to? Power rating? Current distortion? They're not the same thing.

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    "Anything can have a passive harmonic filter included at its input."

    Thats the best answer. Unless you want to remove all of the electronic equipment, VFD's and T8 lighting, you will have harmonics issue. A good way to counter the effects are with filters.
    Chris Hill, EE,ME,GA-CR
    Power Factor Correction

  8. #8
    T.M.Haja Sahib Guest
    Quote Originally Posted by aelectricalman View Post

    Unless you want to remove all of the electronic equipment, VFD's and T8 lighting, you will have harmonics issue. A good way to counter the effects are with filters.
    Quote Originally Posted by Besoeker View Post
    Anything can have a passive harmonic filter included at its input.
    Unfortunately, it increases the energy consumption due to energy loss in the filter which seems to run against the principles of Green building.
    Quote Originally Posted by Besoeker View Post
    And, I ought to ask you what the 10% refers to?
    The answer is in the first post of the thread. I thought the thread had continuity.

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    Quote Originally Posted by T.M.Haja Sahib View Post
    Unfortunately, it increases the energy consumption due to energy loss in the filter which seems to run against the principles of Green building.
    Any harmonic mitigating measure is probably going to do that and add costs. Think about active front end variable frequency inverter drives. The front end bridge changes from a plain rectifier to an IGBT bridge of about the same rating as the output bridge. More complex, more losses, and more expensive.


    Quote Originally Posted by T.M.Haja Sahib View Post
    The answer is in the first post of the thread.
    should not exceed 10% of total load
    It what you put in the first thread. Your post doesn't make that clear.
    But 10% of what load?
    Installed kVA?
    kW?
    Current?

    For example if you had had 100kW of fixed speed motors installed, could you then have only 10kW worth of variable speed drives?
    Of course the ratio of the currents between the VSDs and the fixed motors is most probably going to be rather lower than 10%.
    And it the non-sinusoidal current that causes voltage distortion.

    All I'm asking is that you clarify what the 10% refers to.

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    the IEEE standard for Harmonic total demand distortion ITDD at 5% should be more than enough to satisfy any "green building" requirement.

    this is the limit that utilities use in measuring harmonic emissions from customers.
    NEC 1968 and 1948

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