ssage
From: jarmo.venalai...@schneider-electric.com
Date: 07/27/2015 5:34 AM (GMT-10:00)
To: RE-wrenches
Subject: Re: [RE-wrenches] DC conductor line loss numbers
Hi:
When deciding on voltage drops and otherwise
working out the design of a solar system, one thing that needs careful
atte
E-wrenches ,
Date:
07/25/2015 12:46 PM
Subject:
Re: [RE-wrenches] DC conductor line loss numbers
Sent by:
"RE-wrenches"
You would want to confirm hot temp PV circuit values with chosen Vdrop to
ensure the irrelevant value doesn't drop you out of the inverters'
operational lim
ge-
From: "Chris Mason"
Sent: 7/25/2015 15:20
To: "RE-wrenches"
Subject: Re: [RE-wrenches] DC conductor line loss numbers
It should be noted that the NEC recommendations for feeder circuits are to
do with acceptable voltages at the load, i.e., you do not want your 208
It should be noted that the NEC recommendations for feeder circuits are to
do with acceptable voltages at the load, i.e., you do not want your 208V
equipment running on 200V. PV circuits are not feeder circuits, voltage
drop is irrelevant. Power loss may be relevant, but only in terms of
economic v
I have worked out the area under the daily bell curve. A 2% loss at max current
equals 1% loss average. Maybe this logic could allow some flexibility.
William
> On Jul 25, 2015, at 5:52 AM, Jerry Shafer wrote:
>
> Wrenches
> I have 3 engineering firms and one in-house engineer that only use
Wrenches
I have 3 engineering firms and one in-house engineer that only use 1%
because in the NEC it is stated as a suggestion and not a requirement but
they take this as a must not exceed instead,
I cant change CC as it will be remotely monitored via the Outback
connection, the Engineers refuse to
Jerry,
2.5% loss is fine, especially considering the cost of reducing that
further.
Remember that you are calculating the line loss at the peak power output of
the array, at noon on a sunny day. Since the array will only provide peak
output for a rather small part of the day (unless you have
Hi:
Copper conduction losses are proportional to (current) x (current) x
(resistance). For the same wire gauge, double the current means that the
losses increase by 4X.
Going from 150 VDC to 300 VDC will therefore allow you use 4X thinner wire
and going up to 600 VDC will allow you to use 16X
Jerry,
A long distance wire run is practical now days using a high voltage controller.
Have a look at Schneider and Morningstar 600Vdc controllers. Not sure what you
mean "by nothing can be changed but wire size” but you will have to rewire the
strings into series and protect the wire run.
Lar
Maybe 600vdc charge controller?
Roy Rakobitsch
NABCEP Certified Small Wind Installer®
NABCEP Certified Solar PV Installer®
Certified Advanced Tower Climbing, Safety & Rescue
Wind/PV Design Engineer
Windsine LLC
631-514-4166
www.windsine.org
On Jul 22, 2015 1:52 PM, "Jerry Shafer" wrote:
> Wrench
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