Newbie looking for answers

Discussion in 'What Products are for Me?' started by energypig, Jan 1, 2012.

  1. I live in NW Iowa and have a huge wind farm one mile away. I have monitored the wind for almost 2 years and I am getting ready to get serious about an install. I was thinking of doing either 2 turbines or 1 turbine with small solar. my yearly average wind speed is 16.8 mph. Very windy year round. I would like a grid tie only system and have read every single post on this forum and I am still somewhat unsure what hardware I need. Any input would be great. Sorry I know there are similar posts on here but didn't see any for 2 turbines. I will most likely do Windtura 750's. Thanks for a great working forum:)
  2. leamywind1

    leamywind1 WindyNation Engineer

    Hello EP,
    You may want to treat each turbine as it's own system. Then feeding into the grid for a 220v system at the end. (120v Ac watts per turbine) Then you can just duplicate each one with it's own componets. Same with solar, treated as it's own system.
    Just one thought. :)
  3. leamywind1,
    Thanks for the response but I was wondering why you would double up the components and not wire in series but maybe that is not possible could you tell me why that is not recommended?(only trying to learn)
  4. leamywind1

    leamywind1 WindyNation Engineer

    We do not run them in series because one inverter will lock on before the other or one will goto over volt before the other. Using them in parallel keeps the inverters producig more evenly as they receive power. You can try doing it in series to test your results if you like.
  5. Andy R.

    Andy R. WindyNation Engineer

    Why not 2 windtura 750 turbines to the same buss bar in parallel with 2 inverters in parallel to the same buss bar like a Sun G 250 watt 10.8 to 30 volt inverter for low wind and a Sun G 1000 watt 22 to 60 volt for higher wind connected to a dump load?
  6. leamywind1

    leamywind1 WindyNation Engineer

    You can do it that way too. I had mine like that for a while. Every turbine has it'scharacteristics so doing it a few ways may help find the sweet spot. That is whay i did to find what works the best at my site. Test, test, test. Thses damn inverters have no directions to help out.
  7. Another newbie here - with a similar enquiry.

    Larry Leamy has helped me with the generation side - but this question is about the usage (grid-tie application with no batteries) and connection to the mains. I thought I would post it, as any replies could be useful to others.

    My house is served by two electricity meters - one for the house cicuits; the other for the swimming pool. Both meters are 120V, 3-wire, split phase.

    The pool circuit has two pumps, each about 1.5HP (1100W), one for the filters; the other for the solar heating panels (not PV - just thermal). One pump runs from 1ph at 120V; the other is 240V and runs from both phases.

    So, if I connect my Sun G 1000 watt WDL to either of the mains phases, I think I will have a problem IF the wind turbine is generating at the the same time as one of the pump motors is running.

    If I understand the operation correctly, the GTI works by 'taking over' the mains supply. My mains is 125V, so, when the wind blows, the GTI control circuit will cut in at say, 126V, and try to feed the motor - which it will not be able to do, because there will be insufficient power.

    Not only that, as the GTI is rated at 1000W, (and will only supply this power in a gale), if it tries to supply the motor, the current draw will be too high and damage may be done to the GTI.

    This argument (question) applies to whichever phase the GTI is connected . . .

    I think I have answered my own questions - but would be grateful for confirmation, or otherwise, please, by a resident expert here.

    Of course, if I am correct, the problem then is - is there a workaround for the pool supply?

    If there is not, I suppose I will have to connect to the house supply - which has other problems of turbine siting v cable runs, etc.

    Here's looking forward to some discussion . . . .
  8. Minnesota

    Minnesota WindyNation Engineer

    Paul, there is no problem. The GTI does not take over anything. It just contributes watts to the grid. It stops, slows, or reverses the associated meter depending on the type of meter you have and what power you are using at the time.
  9. Thanks Minn, but . . . in that case, it seems I do not understand the operation of a GTI.

    If the potential of the grid remains higher than that of the GTI, then current will surely not flow from the GTI?

    Conversely, if the GTI potential is higher than that of the grid (which is how I thought the synching of a GTI worked) then no current will flow from the grid?
  10. Sorry to harp on - trying to understand - found this (I made the text red):

    A grid tie power source has to synchronize its frequency, phase and amplitude with the utility and feed a sinewave current into the load. Note that if inverter output voltage (Vout) is higher than utility voltage, the GTI will be overloaded. If it is lower, GTI would sink current rather than source it. In order to allow the electricity flow back into the grid, "Vout" has to be just slightly higher than the utility AC voltage. . . . . . Because the grid acts as a source with a very low impedance, the GTE normally works as a current source, rather than a voltage source.

    Anyway - I suppose my concern is that, whichever phase the GTI is connected to, will the GTI not be overloaded if the turbine is providing power at the same time as one of my 1.5hp motors kicks in?
  11. Minnesota

    Minnesota WindyNation Engineer

    The explaination you posted is there to explain to readers how they work. As part of the synchonization process they all measure the line voltage amplitude and set their GTI voltage just a fraction higher before they start feed the line. They then monitor the line constantly to maintain "the upper hand."
  12. Thanks again Minn.

    So, am I right to say that, if the GTI cannot supply sufficient current to run the pump (which of course it will not) - the mains grid will supply the balance of the required current (which, of course, will be most of it) - and - there will be no damage to the GTI?

    Sorry to labour the point - but better safe than sorry!
  13. Minnesota

    Minnesota WindyNation Engineer

    Yup. You got it. I have 6 GTIs running and they all work just fine. When there are watts to be contributed to the grid, they do it seamlessly. This is how the power companies do it too ... multiple power plants all feeding the same wires.
  14. Great! Thanks again.

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