Author Topic: Question on grounding?  (Read 1472 times)

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(unknown)

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Question on grounding?
« on: September 16, 2008, 11:05:13 AM »
Hi, what is best way to protect your wind generator from lighting strikes?

Thanks in advance for any help received.  
« Last Edit: September 16, 2008, 11:05:13 AM by (unknown) »

DanG

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Re: Question on grounding?
« Reply #1 on: September 16, 2008, 08:13:13 AM »
The best store-bought lightning protection system may be the guarantee it's sold with...


http://www.dehn-usa.com/dehn-Application-Guides-pubcid1.html <-- their Lightning Protection Guide is a good read even if it is a showcase for 'their' components and worth the 16 megabyte download.


http://lecglobal.com/solutions/lightning/protection/ <-- another form of protection... Dissipation to prevent a static charge 'leader' from getting energetic enough to make the jump to full conduction.


The average lightning strike is 15,000-25,000 Amps so you want multiple methods in multiple areas to keep the direct strike out of your life.


Without spending as much for lightning protection as you did for the tower or wind turbine itself the best you can hope for is avoiding damage from a near-miss that saturates metal for hundreds of feet in all directions with high voltage surges. This has been posted on many times, use the google search function to see some of the best this group can come up with...(be sure to use the " -ungrounded " search term so Fieldlines user Ungrounded lightning Rod's posts don't clog the results (no offense ULR))

« Last Edit: September 16, 2008, 08:13:13 AM by DanG »

wooferhound

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« Last Edit: September 16, 2008, 08:36:32 PM by wooferhound »

luv2weld

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Re: Question on grounding?
« Reply #3 on: September 17, 2008, 07:24:33 AM »
My first thought was "Keep it in a box in your basement!!"


But after reading some of the things that have been posted

here about close proximity strikes, maybe that's not a good

idea either.


Not trying to "P--- you off", just injecting a little humor.


Ralph

« Last Edit: September 17, 2008, 07:24:33 AM by luv2weld »
The best way to "kill time" is to work it to death!

SparWeb

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Re: Question on grounding?
« Reply #4 on: September 17, 2008, 12:08:15 PM »
Simple question with no simple answers.

As soon as lightning enters the wiring of the windmill, solar panel, power wires, data cable, or any structure, the huge voltage can deliver a similarly huge current.  Anything else connected to the component that's struck will also be vulnerable to a high indirect voltage.  The indirect voltage can come in at high or low potential, forward or reversed polarity, and a very high or low current can result.  All very hard to predict.  No, impossible.


If lightning currents flow in loose wires, they can actually move or whip around.

If lightning currents flow through a battery, the liquids could vaporize and explode.

Lightning has been known to heat small wires enough to vaporize them (that's anecdotal).


Your best protection is a thorough and systematic attention to grounding the whole system from tower to the inverter.  One arrester wired to a stake in the ground will not do.  Could even make things worse.  The grounding system has to suit the system you have, so it's hard to put a bunch of general advice together.


If you subscribe to HomePower magazine, you can read their Code Corner for a lot of instructions.


One last point: don't listen to me.  My wind turbine isn't perfectly protected either!  I still don't have a ground bus separately installed from the negative bus bar...

« Last Edit: September 17, 2008, 12:08:15 PM by SparWeb »
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DanG

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Re: Question on grounding?
« Reply #5 on: September 17, 2008, 01:04:35 PM »
The issue of "Home Power" I got today has this question.


Roughly put, they recommend an arrestor in four places - top and bottom of tower and one just before the equipment being protected inside the building... plus one at the AC panel.


Sounds like good advice to me but I could never afford 'their' equipment.


Full Q&A text here:


http://www.homepower.com/article/?file=HP127_p12_ATE_1

« Last Edit: September 17, 2008, 01:04:35 PM by DanG »

jimjjnn

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Re: Question on grounding?
« Reply #6 on: September 18, 2008, 09:33:39 AM »
When I lived in a modular home. We still had a temporary pigtail lying on the groung to the power pole.

It was hit by lightning in the middle of the cable and was vaporized for 3 feet of length.

Power company had to come out and finish the job correctly immediately as my neighbors had lost power and lots of valuable electronic equipment that the power company had to pay for due to their lack of diligence in the installation.

The cable they used was 1 1/2 inches thick.


It sounded like a bomb went off at the time.

« Last Edit: September 18, 2008, 09:33:39 AM by jimjjnn »