# 25 kv substation



## bobelectric (Feb 24, 2007)

I went on a call to a facility substation that had the lineside wire to a lightning arrestor blown off.Is there a was to check an arrestor this size? 25 kv.


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## Zog (Apr 15, 2009)

Insulation resistance test, test at 5kV, should be >20M
Check ground terminal to ground is <0.5 ohms
Perform a watts loss test


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## bobelectric (Feb 24, 2007)

Thanks. Looks like call to Pete Mckensie at Met testing.


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## bobelectric (Feb 24, 2007)

Went to it today, all three phases had loose connections. Wire broke off,ok now.


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## Big John (May 23, 2010)

No back story?! No pictures?! :jester:

You end up doing any arrestor testing? How'd you find the loose connections?


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## bobelectric (Feb 24, 2007)

We shut down the substation, 7.5 MW,using the air switch after clearing the loads. We couldn't get the bucket truck close because of low
phone lines so we used a 10 foot stepladder to do a visual inspection.Found no burns, just 35 years of weather. Checked all connections ,I held breath and threw air switch and heard good humming. Left at 9:00.We did find a dead racoon next to a bushing on xfmr.


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## Zog (Apr 15, 2009)

bobelectric said:


> Went to it today, all three phases had loose connections. Wire broke off,ok now.


Partial Discharge surveys would have found that, great tool for that type of installation.


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## bobelectric (Feb 24, 2007)

Zog, we just were there to check out the L/A problem.


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