[RE-wrenches] Extensive Lightning Damage to Modules

[Solarguy]

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

ntrei at 1scom.net 

817.917.0527

 

 

 

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Jeff Irish
Sent: Friday, September 07, 2012 9:41 AM
To: RE-wrenches at 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

jeff at 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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