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#184613 - 02/13/09 11:55 PM Solar panel installation
Check Pilot Offline
Member

Registered: 11/25/05
Posts: 145
Loc: Edmonton Alberta Canada
I posted this on the Canadian forum last week and wound up with zero repies, so I'm trying it here. Hoping to get some help if anyone wants to give it a go.

Thanks.
___________________________________________
We have an Edmonton, Alberta, Canada client that wants to install a fairly low power - i.e. 10 KW solar panel, solar tracking installation. Although it's reasonably low powered the system would present some technical issues with battery current to the inverters. We know the cables to the inverters will be fairly large KCMil stuff but.....

However,

He wants, but we have not been involved with, a grid tie system before and would like anyone's experiences with carrying out this kind of work at these kind of power levels. Our client wants to do a grid tie system which you all know needs the POCO involved as well. So far we have their preliminary approval to tie in to their grid, providing we have all the necessary Phase/frequency requirements met along with the usual non-back feed requirements when their system quits. We have researched ad-infinitum with suppliers and distributors and of course the internet. Canadian knowledge and advice seems in short supply however.

I'm looking for thoughts/advice from anyone with prior grid tie experience that might be able to tell us the traps and pitfalls you might have experienced that go along with a solar system grid tie installation.

Thanks,

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#184615 - 02/14/09 12:44 AM Re: Solar panel installation [Re: Check Pilot]
frenchelectrican Offline

Member

Registered: 02/06/03
Posts: 938
Loc: Wi/ Paris France { France for ...
Dave., I know we did talk about a little in the chat room sometime back however.,

I will make few more addemendments what I should cover it with our conversations.,

The issue is weight of photocell if it will be mounted on the roof that roof structure that need to be check with the building engineer to make sure they can take both photocell weight plus snow load as well.

I am not sure how hot it do get in your area Dave., but if you run any conductors on roof structure watch the derateing carefully on that one due the solar system is pretty much contionus operation during daylight hours even with cloudy days it will run but at reduced capaity.

The quirk is each one is diffrent and warranty wise that part I only have limited info on them.

As far for Cananda code requrement for disconnection switch IMO for myself it should be near the solar panel for safety reason { someone told me put in interlock switch so that way it will lock out the inverter when the disconnection switch is open.}

other pitfalls it hard to say but I will let other members here to see if they can pitch in with more infomation with this set up.

Merci,Marc
_________________________
Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)


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#184620 - 02/14/09 09:06 AM Re: Solar panel installation [Re: frenchelectrican]
Tom Offline
Member

Registered: 01/01/01
Posts: 1069
Loc: Shinnston, WV USA
Try this site

http://nmsu.edu/~tdi/Photovoltaics/PV-Energy.html

I can't say that you'll find what you need to know, but if you can't, send an e-mail to jwiles@nmsu,edu

John C. Wiles from New Mexico State University is one sharp fella on photovoltaic systems. He has written several articles for the IAEI and I was able to attend a seminar he put on at our chapter meeting.


Edited by Tom (02/14/09 09:07 AM)
Edit Reason: Spelling, as usual
_________________________
Few things are harder to put up with than the annoyance of a good example.

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#184625 - 02/14/09 11:20 AM Re: Solar panel installation [Re: Tom]
mbhydro Offline
Member

Registered: 02/21/03
Posts: 340
Loc: Winnipeg MB Canada
Here are two canadian suppliers that may be of help if you have not tried them yet.

This guy is from Lumsden SK
http://www.kellnsolar.com/devSite/index.php

And this one is located here in Winnipeg:

http://www.solarengineers.com/Divisions/Residential/tabid/57/Default.aspx

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#184760 - 02/20/09 06:31 PM Re: Solar panel installation [Re: mbhydro]
ChicoC10 Offline
Member

Registered: 05/30/07
Posts: 169
Loc: CA
The only systems I've seen in Northern California are grid tied and there is no battery system involved.
The inverter is chosen for its output voltage at a given current capacity, a range of acceptable DC input voltages and freq/phase matching is handled by the inverters internal electronics.
The inverter does nothing at night and it shuts down (even in the brightest daylight) when it loses it's sense signal from the mains during a power failure.

I think (but have no actual proof) that this is due to all of these systems being subsidized by State/POCP rebates. It wouldn't do for the end user to go and disconnect the thing they paid for half of from the grid and run it independently now would it? If I had just paid for a system and found out it wouldn't work in a 4 day power outage (like we had about this time last year) I would be upset. But I digress...


I have seen inverters for sale on-lone for off-grid use but don't know if they could be used in both grid-tied and off-grid modes or if the POCO here would allow it.


That said, the systems I have seen, including one capable of running a full 240V 200A service in bright daylight, all used a series-parallel network of panels to bring both the DC voltage and current up to levels that worked well with the inverter while not requiring huge feeders. It would stand to reason that a series- parallel network of batteries could accomplish the same thing. Might not be cost effective though.

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#184778 - 02/20/09 10:55 PM Re: Solar panel installation [Re: ChicoC10]
Check Pilot Offline
Member

Registered: 11/25/05
Posts: 145
Loc: Edmonton Alberta Canada
Thanks to all for your inputs.

We started the installation, only to have it stalled a bit because the client wanted to have a solar sun tracking system go along with it. That upped the price a bunch. To me, that might not be a "bright" idea since it involves moving parts that are going to need servicing every so often to make sure it's still tracking the sun. (Good for me for the service contract, but not good when it fails unexpectedly).

The solar trackers make installation about $15,000 more for this one and it now seems that the solar panel cost is starting to diminish percentage wise compared to the system cost.

When we worked out the payback time (again) for this installation the clients wife kind of choked a bit, but they are still fairly young and in their early 40's and still want it done, so it will be paid off when they reach the age when their kids are done with their University degrees in 15 years or so.

Meanwhile, the solar panel mounts are proving to be a challenge, as is the annoyance of the City ordinances regarding fire containment for electrical storage "rooms" as it has now become. Unfortunately, there are no unambiguous guidelines from the Canadian Elaectrical Code on solar power battery on-the-grid requirements, so we are kind of winging it from what we can get from other battery room rules and hoping the City AHJ guys can be convinced that we are at least trying.

If any of you here are involved in any of this kind of stuff and the silly complications arise, I'd appreciate your input. Even more so my guys doing the actual work on the outside at minus 15 degrees Calcium (plus 258 kelvin :-)) would really like to know when this "adventure" might come to a successful completion for this customer.

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#184800 - 02/21/09 11:32 PM Re: Solar panel installation [Re: Check Pilot]
Check Pilot Offline
Member

Registered: 11/25/05
Posts: 145
Loc: Edmonton Alberta Canada
Today we finally got the mounts and solar az-el trackers working in response to the daily sun-up and sun-down times. What an amazing visit to see about 50 little step motors all working in unison! Almost like a bunch of little R2D2 guys doing their thing. At sundown tonight the panels all swung to the east at exactly the proper times to get aimed to the morning sun capture.

During the day around 13:30 - which is about solar noon here we got about 50 amps going to the batteries from the panels so I expect that should work for a grid tie system when we get that hooked up.

Thanks for all the links as well guys.

Anybody care to jump in with more experience? I appreciate anything you might have that might be anecdotal or otherwise.

Monday morning we have a meeting with the AHJ to see about battery vaults too, so that might be interesting if we have to change it.

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#184801 - 02/21/09 11:44 PM Re: Solar panel installation [Re: Check Pilot]
pdh Offline
Member

Registered: 01/20/05
Posts: 354
On a large scale, solar tracking only makes sense if you are reducing the density of panel area to land area. When the sun angle is lower, the solar power incident on the land area is reduced. Trackers don't improve on that unless the panel area is nominally less than the land area. If tilted panels don't block each other somewhat, then at high noon you have gaps between the panels and no noon peak of solar power. The arrangement where tilting does have a benefit is an arrangement with less panel area and less power at noon than if the panels were at full land density.

If you have one big panel, tracking can make sense. But it is true this involves moving parts, a control mechanism (based on timing or sensing), less reliability, and greater maintenance.

The benefit of aiming the panel is lost on cloudy days. Then light comes in at all angles. This needs to be taken into consideration if you want solar power during these times. Certain multi-angle solar concentrators, such as the Winston Collector, take light from multiple angles and concentrate it. Photovoltaic cells also operator more efficiently at greater light+IR concentrations. And the multi-angle concentrators take in more light on cloudy days.

http://www.paws.dircon.co.uk/solar.htm
http://www.appropedia.org/Understanding_Solar_Concentrators

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#184802 - 02/21/09 11:53 PM Re: Solar panel installation [Re: pdh]
Check Pilot Offline
Member

Registered: 11/25/05
Posts: 145
Loc: Edmonton Alberta Canada
Thank you ever so much pdh. The links are very much appreciated.!!!

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#184851 - 02/23/09 07:29 PM Re: Solar panel installation [Re: Check Pilot]
pdh Offline
Member

Registered: 01/20/05
Posts: 354

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