"Delta SS's at the tracker discos and in the inverter room were
unaffected which I thought was odd."
This is not surprising at all since those don't start clamping until
around 7000+ volts.
Check out the comparison video about this very subject on the MidNite
Solar web site.
BTW, there are disconnecting PV combiners starting to ship now with
built in SPD 600's..
boB
On 9/7/2012 5:58 PM, Solarguy wrote:
In 2006 we installed a dozen Spire 85W modules w/clear backing in
pairs as skylights. Shortly after, the building attached to the
electrical equipment room, took a direct lightning strike to the wind
anemometer 10 feet above the roof. Of the 12 modules four suffered
damage to their diodes. Several were completely vaporized, there was
nothing remaining except powder and the leads. Others had burnt diodes
with leads that had clearly been very hot. Other modules were just
fine, the damage seemed to be random with all 12 in series.
The 4 trackers, the closest ~70 ft. away, are grounded with two spools
of buried #8 bare copper and Uffer grounds in the concrete piers were
untouched. Delta SS's at the tracker discos and in the inverter room
were unaffected which I thought was odd. 5 Sunny boys & 2 Sunny
Islands in the same room were toasted. Our only experience with
lightning.
Jim Duncan
North Texas Renewable Energy Inc
www.ntrei.com <http://www.ntrei.com/>
NABCEP PV 031310-57
TECL-27398
nt...@1scom.net <mailto:nt...@1scom.net>
817.917.0527
*From:*re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Jeff
Irish
*Sent:* Friday, September 07, 2012 9:41 AM
*To:* RE-wrenches@lists.re-wrenches.org
*Subject:* [RE-wrenches] Extensive Lightning Damage to Modules
A customer of ours has recently suffered lightning damage to 31 out of
160 top of pole mounted modules. This is the first time in 10 years
that I've seen modules damaged by lightning. Lots of inverter GF
fuses and a few inverters, but never modules. We're trying to
determine if it was caused by the lightning flash irradiating the
modules or ground currents.
The array consists of 16 DP&W top of pole mounts with 10 modules each,
arranged in a square of 4 poles E-W and 4 rows N-S. The poles are 13
feet center to center E-W and the N-S row spacing is about 50 feet.
The poles are 6 inch galvanized Technoposts, augured 5 -- 7 feet into
the firm ground, connected with a network of about 160 feet of bare #6
copper and at least 8 copper plated ground rods. Altogether we have
about 130 square feet of bare metal surface area connected and buried
in the ground at and around the array.
The customer saw lightning strike just after dawn a few weeks ago a
couple hundred feet to the southwest where it also destroyed two
utility pole mount distribution transformers and ran along the utility
wires 100 feet south of the array. The inverters are 200 feet NW and
suffered no damage. The array and modules look totally fine, except
some of the J-boxes are deformed from heat. Opening the J-boxes shows
varying levels of damage to one or more diodes, from discoloration to
being broken and cracked open.
The odd thing is the pattern of damage (we've tested all the modules
individually for Voc and Isc). Only modules in the south row of 4
poles are damaged, and the damage is concentrated on the modules
closest to the ground; modules higher up in the air appear OK. Also,
damage is less frequent as you move east, away from the direction of
the strike.
If it was caused by ground currents, why would the current want to go
up the poles, why only the southern row of poles, and why damage more
modules closer to the ground and not those at the top? Is it possible
a flash near the ground irradiated the modules causing a current spike
and the southern row shielded the other rows from most of the flash?
Anyone have experience with this?
Jeff Irish, PE
President
Hudson Solar
13 Hook Road
Rhinebeck, NY 12572
T.845.876.3767x110
F.845.876.3912
j...@hudsonsolar.com <mailto:j...@hudsonsolar.com>
/Solar Electric Systems/
/NYSERDA Eligible PV Installer/
/NABCEP Certified Solar PV Installer/
/NABCEP Certified PV Technical Sales/
HudsonSolar.com
<applewebdata://B5F2562A-2B67-4161-84E4-42F12DC28720/www.hudsonsolar.com>
2011 NYSERDA Excellence in Quality Award | 2011 NYSEIA Award Winner |
2009 Best of the Hudson Valley | 2008 SunPower Dealer of the
Year | EDC Business Excellence Award for Innovation
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