[RE-wrenches] Transmitting 15kW 3600ft Off Grid.

[Mac Lewis]

Hello Dan,

I think the power requirements are way too low to consider DC
transmission.  Readily accessible parts are a real concern.

However, why not think about going well above 480?  How about 10 kV or
above?  There are a lot of companies supplying utilities that have cheap,
relatively efficient and reliable single phase transformers in that range.
You can overbuild your power system to make up for the transmission loss
and be way ahead.

Good Luck!

On Mon, Jan 10, 2022 at 6:37 AM Pieter Huebner <
pieter at offgridenterprises.org> wrote:

> It sounds like you are working on an Island near Jones port Maine ( Norton
> Island). The site had or has a Bergey 7.5kw XL-R wind turbine, on a tilt
> tower which is almost impossible to tilt, a solar array on a stacked log
> tower, Kubota generator, flooded cell lead acid batteries and Outback
> Inverters. Your assessment of the system is 100% correct, bad workmanship,
> and little or no maintenance. The original design was poorly thought out as
> well. The poor workmanship was not limited to the energy system, the
> electrical infrastructure had issues as well. The original installer was in
> way over his head. I have been to that site at the bequest of the original
> owner to repair the wind turbine years ago.
>
>                 My suggestion is that you evaluate the existing equipment
> and infrastructure, and salvage what you can then start with a fresh sheet
> of paper. The electrical loads need to be mapped, for example the original
> owner had a hot tub at the main house.
>
> The site would lend itself well to a micro grid system. if you like we can
> have long discussions about this site and I will be happy to share what I
> know about it as well as share my experiences with AC and DC distribution
> for off grid sites.
>
> Pieter
>
>
>
>
>
> *From:* RE-wrenches <re-wrenches-bounces at lists.re-wrenches.org> *On
> Behalf Of *Foxfire Energy
> *Sent:* Monday, January 10, 2022 5:35 AM
> *To:* re-wrenches at lists.re-wrenches.org
> *Subject:* [RE-wrenches] Transmitting 15kW 3600ft Off Grid.
>
>
>
> Hi Guys, Got a good one for you.. We were tasked to refurbish a Stand
> Alone (aka Off Grid) power system on a 100 acre private resort island off
> the New England coast a few years back.. The system has a 12kW(AC)/ 48VDC
> power center (@120/240VAC) with a 10kW Bergey wind turbine, 3kW of Solar
> and a 12kW Diesel Generator.. It currently powers two main lodges and 10
> private cabins.. The system was never installed properly and had
> significant damage when we got there (no system ground, evidence of several
> lightening strikes, open/corroded connections, and poor workmanship in
> general)
>
> The new owners want to build a third lodge at the other end of the
> island.. Some 3600ft away, and want to feed full power from the existing
> system to the new lodge.. Thing is, the new owner is pretty brainy (keeps
> me on my toes).. My first thought was to bump the 120/240VAC up to 480VAC
> and send it on like 4/0AL and back down to 120/240VAC at the new lodge
> (we've done it before).. The new owner wants to launder the AC to DC and
> back for transmission.. Says DC for transmission is the new Cats Pajamas
> because of the efficiency.. News to me.. Anyone have experience with DC for
> transmission? Again.. I'm shooting for 15kW (including 25% for continuous
> duty), 3600ft, 600V wire (but could go with a different wire) and a line
> loss under 5%. TIA db
>
>
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-- 



Mac Lewis

*"Yo solo sé que no sé nada." -Sócrates*
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