[RE-wrenches] Step-up/Step-down Transformer question

[Darryl Thayer]

The single phase - 3phase change is too difficult and expensive.  Stay with
single phase.  I have done this successfully with a step up and down
transformer.  You, of course, need to select the correct transformer.
Transformers seem to have a price advantage using standard voltages.  For
example, starting at building 240 to 480 and then use 480-volt inverters.
This will require longer strings for the 480-volt single phase inverter.
 another way is to use 240 to 240-480-volt and carry a neutral.  then
select inverters that can operate with no neutral, I call them floating
output.  This cuts current in half, voltage drop or rise by 1/4 allowing
smaller wire.

On Mon, Sep 17, 2018 at 11:42 AM Lorenzo Ortiz <lorenzo at cal-solar.com>
wrote:

> Wrenches,
>
> We have a PV array situated about 900' from the POI (240V 1PH). We
> initially spec'd (5) 11.4kW inverters and the combined output would be
> 238A. The wire size required for this current over that distance is cost
> prohibitive.
>
> A solution was to use a single 50kW 3 phase inverter at the array and then
> convert it to 240V... somehow? Is anyone familiar with how to go about
> doing this? My thought was to have a step down transformer at the POI and
> pull off two legs to get 240V. Is this even a thing?
>
> The other, more expensive option is to use a step up transformer at the
> array and a step down at the POI to get us a smaller wire size.
>
> Thanks for any input.
>
>
> --
> *Loren Ortiz   Commercial PV Designer*
>
>     loren at cal-solar.com <lorenzo at cal-solar.com>*  (530) 274-3671*
>
>
>
> <http://californiasolarco.com/referral-program/>
> *Showroom located at: 149 E Main St. Grass Valley, CA 95945*
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