AC power line question

[John Teller]

Definitely some sort of fault indicator.  It'll stop blinking once 
everything is back to normal.

Check out this link to SEL (Schweitzer Engineering Laboratories) or 
Google "overhead fault indicator"

http://www.selinc.com/FCI/Overhead/

---JST


On 06/30/2012 04:41 PM, Nan and Sandy Sanders wrote:
> This is the first time I have seen these flash and they have been 
> there at least 3 years. I think they may be some sort of surge sensor. 
> We were taking some really hard power hits here for a while.
>      Sandy
>
>
> At 02:59 PM 6/30/2012, you wrote:
>> Those are most probably some sort of potential indicator.  It's kind 
>> of a weird circuit in that one end is physically connected to the MV 
>> line while the other end is capacitively coupled to ground.  At those 
>> voltages you don't need much current to flash an LED - which would 
>> indicate that the circuit is live.
>>
>> It's odd that the power company would put up something that flashes 
>> when everything is powered normally, as this generally prompts calls 
>> from all and sundry who normally associate flashing lights with 
>> problems.  I was under the impression that power companies tended to 
>> use mechanical devices that displayed a red or green flag and were 
>> driven by magnetic flux developed around an MV line that was carrying 
>> current.
>>
>> Here's a link to an image of an install of some current sensors 
>> installed in Australia:
>>
>> http://www.spottydog.us/pix/electrical/adelaide_install_lower_view.jpg
>>
>> In this picture you can see the mechanical indicators - they are the 
>> three devices attached near the dampers just beyond the disk 
>> insulators (the line post insulators on top are actually the current 
>> sensors).
>> That's a three-phase delta system, which is why the transformer is 
>> connected to two lines.
>>
>> ---JST
>>
>>
>>
>>
>> On 06/29/2012 11:52 PM, wb5mmb wrote:
>>> We just had a line of storms blow through Northern Virginia with 
>>> many hard power hits but power never went all the way down. On the 
>>> power pole in front of the house there are cylinders about 3" in 
>>> diameter and 3" long hanging from each of the 3 high voltage lines 
>>> about 1' from the insulators. Each cylinder has a blinking red led 
>>> on it.
>>>  Two questions, what does it mean when the LEDs are blinking and how 
>>> do you power an led on a box hanging on a 13KV line that looks like 
>>> it could handle several hundred Amps.
>>>      Sandy
>>>      WB5MMB
>