How does a helicopter bond to a HV line?

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Lo_volt

Joined Apr 3, 2014
316
...No shock when I touch a single wire. Yes, I need to be careful, but no, touching any one wire gives no shock. But I only do it in dry weather. The big thing is to be well insulated from ground.
MisterBill2 you're a braver man than I!:eek:
Here's a thought: If I'm floating in air, next to a high voltage transmission line and I grasp the line in my hand, would the potential at my feet (solely due to the field) be different enough from the potential at my hand such that current will flow? This differs from MisterBill2's situation only in the higher voltage of the HV transmission line.

As I understand, the helicopter technician is wearing something akin to a chain-mail suit to ensure that his body doesn't see differences in potential from head to toe. I don't know about the pilot.
 

MisterBill2

Joined Jan 23, 2018
18,176
At those high voltages there is a small amount of current flowing into the air, or something like that. I have experienced the feeling approaching a wire connected to about 6000 volts AC, and a good insulation jacket. At that voltage there is current charging the capacitance of the surrounding air. In the hard vacuum of space it would not be an issue, probably.
 

SamR

Joined Mar 19, 2019
5,031
There was a high voltage feeder line on the edge of our parking lot at work that feeds the densely populated St. Simons Island. In the dark and moistly humid seaside atmosphere, you could both see and hear the corona discharge coming off of it into the atmosphere. Not just a 60 cycle hum but snapping and crackling bluish arcing into the atmosphere. Not long sparking but out to an inch or two of the conductors and not constant. It would continuously start and stop along the wire. Quite a sight and sound in the still of the night. Not all the time but when the air was still, moist and humid it would crackle and put on a show.
 

Lo_volt

Joined Apr 3, 2014
316
SamR, your note about St. Simons Island reminds me of a former co-worker of mine who told of similar arcing and crackling on power lines as he was traveling along the Florida Keys. His chat with a local revealed that the power company will hose down the poles and insulators to clean off the salt deposits from the seawater that splashes and sprays near the lines.
 

Reloadron

Joined Jan 15, 2015
7,501
SamR, your note about St. Simons Island reminds me of a former co-worker of mine who told of similar arcing and crackling on power lines as he was traveling along the Florida Keys. His chat with a local revealed that the power company will hose down the poles and insulators to clean off the salt deposits from the seawater that splashes and sprays near the lines.
Here in Cleveland, Ohio we don't have any seawater spray but have plenty of salt. Every winter thousands of tons are dumped on the Interstate highways. Traffic creates a salt mist which begins clinging to utility poles. One spring the conditions were just right with a light drizzle and the wood utility poles began arcing and burning. It was bizarre. I was driving to work going north on I-271 and witnessed it. When I lived in CA, the LA area, the power company used deionized Grade A water (Type 1) to wash down the power line high voltage insulators of the grit caused by smog. Pretty cool to watch a helicopter with a water tank and high pressure pump wash down high voltage insulators. Another example of the use of a helicopter in conjunction with high voltage transmission lines.

Ron
 

SamR

Joined Mar 19, 2019
5,031
One day we had a plant feeder line insulator fail and that was one of the few things our plant electricians didn't handle. I happened by and was watching and somehow the GA Power Lineman we had called in for the job and I got to talking with our electrical shop supervisor who was overseeing the job. He was telling us that they had a regular routine maintenance schedule for feeder insulators. They would be replaced and the old one was then "sand-blasted" with ground corncobs to clean them to be reused. The just plain atmospheric grime had to be routinely removed by non-abrasive blasting of the porcelain surface to prevent arc-over of the insulator hat chains used.
 
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