Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Generator var import and export

  1. Aug 13, 2012 #1

    I'm working with this, so I should actually know this already, but... :P

    I'm just not sure how this actually works.
    Googled a little and found this forum with a good thread https://www.physicsforums.com/showthread.php?p=3973084
    But for me, this is too much math. Can someone explain this a little easier for me? Almost i laymen term?

    In the switchboard I have DEIF protections (PPU3/GPU3), which I set up the protections for high voltage, var import, var export, reverse power etc.. I would really like to have a better understanding of what I do instead of doing it the way I do now. I have a "recipe" on how to set up the protections for this, but this is not telling me what I actually do :P
    Since the drawings I work with is copyrighted, I can't upload this, but I guess it is the same more or less all over the world...?

    The generators are energized (excitation), I got voltage, and I connect it to the switchboard.... Setting up a PPU3 og GPU3 is not so difficult, but it would be nice to know some more when I get specific problems with for example loss of sensing to the AVR...

    We use mostly DECS-100 for AVR with either, PPU3 (paralell protection unit) or GPU3 (generator protection unit)..
  2. jcsd
  3. Aug 13, 2012 #2

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    i dont know a thing about your model numbers

    you haven't said whether you understand the magnetic circuit in an alternator.
    and that's the key to understanding how they behave in parallel.
    perhaps you'd post a picture of one , and ask some questions to guide the discussion?

    Usual teaching practice is to jump immediately to phasor diagrams
    but what Bassalisk and i did in that link you referenced is talk our way through some pictures he had, to paint a mental image of the magnetic flux from which the formulas naturally come.

    unfortunately the links to them now give "not found" error.

    In my day Basler was a friendly helpful outfit. I once called them and explained i was maintaining some of their equipment, and they sent me a package of helpful "how it works" info. Mind you that was ca 1975 and it was magnetic amplifier voltage reulators... try it and see if they're still the same friendly midwesterners they were then.

    there's two 'next steps'

    old jim
  4. Aug 14, 2012 #3
    Well... Probably not in the same way you do. I'm more practical than theoretical you could say.

    I mainly work on the switchboard, and not the generator. But it is in the switchboard I need to set up the protections and therefor I want to understand this a little more.
    Had a Service Engineer from Basler with me once, but the AVR is not something i normally configure..



  5. Aug 14, 2012 #4

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

  6. Aug 16, 2012 #5

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook