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Join Date: Oct 2012
Posts: 4

LA Rating Calculation

10/30/2012 9:15 AM

Dear Sir,

I wish to know how one can decide the rating of LA ie if we consider for system 220KV the rating of would be 198 KV,lly for 132KV the rating of LA would be 120KV .Is there any specific formula for such evaluation.

Pl.can any body confirm and how can we decide symmetrical fault current for relay.

Rgds,

Mayur

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Guru

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing. Kettle's on.
Posts: 19628
#1

Re: LA rating calculation

10/30/2012 9:17 AM

<...LA...>

Luton Airport? Los Angeles? Lightning Arrester?......

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#2

Re: LA rating calculation

10/30/2012 9:53 AM
Guru

Join Date: Oct 2008
Location: 34° 34' 21.60" N, 92° 55' 42.28" W
Posts: 20975
#3

Re: LA Rating Calculation

10/30/2012 10:33 AM

SInce you give no useful information in your post, it is impossible to answer the question.

LA?

Location?

Regulations in effect?

Knowlegable electrician on-site?

Safety officer on-site?

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Join Date: May 2010
Location: Liverpool, NY
Posts: 568
#4

Re: LA Rating Calculation

10/30/2012 1:23 PM

Any reputable manufacturer of lightning / surge arresters will have an application guide or table to help you choose the correct arrester rating for your system configuration (voltage level, delta or wye, grounded or not, etc.). For example, look at this guide from ABB:

Check the web for manufacturers' info, and you will see that they all use pretty much the same ratings.

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Join Date: Dec 2008
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#5

Re: LA Rating Calculation

10/30/2012 6:09 PM

The rating calculation for Lance Armstrong just recently went deeply into negative numbers. The sad part is that Livestrong is a noble organization that might not exist without those temporary yellow jerseys.

I'm not going to give this an OT because I feel like being a CRIMINAL today.

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Join Date: Aug 2007
Location: Ohio USA
Posts: 557
#6

Re: LA Rating Calculation

10/31/2012 12:51 PM

Surge arrester selection will depend not only on line voltage, but also the system being protected (transformer, line, static VAR compensator, etc.) and the type of earthing associated with the system. Feel free to return with additional questions once you are familiar with the basics.

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