What are these called
1 - 20 of 27 Posts
Joined
·
44 Posts
No, the two dark grey things hanging under the insulators that looks like small transfomers
Joined
·
489 Posts
I work in stations and never seen them hanging like that , but to me it looks like a reactor of some sort
Joined
·
3,830 Posts
I think they are traps or filters for switching and other signals that the utility transmits on the lines.
Joined
·
44 Posts
Any way, you got the correct location
Joined
·
714 Posts
Powerline ethernet (high speed internet) filters?
Joined
·
17,035 Posts
Don got it. They're line traps for high frequency transmission over the power line.
Joined
·
44 Posts
isn't these systems old (using power lines as communication cables) i though today's method was the OPGW's (optical ground wire) for communications between stations
Joined
·
17,035 Posts
I know they often include fiber in the static lines now, but I don't claim to know much about it or the old line trap systems; I've never worked on either.
I think Celtic has run a bunch of OPGW, he'd probably be more help.
Joined
·
3,830 Posts
I think that fiber is being installed on most new transmission and larger distribution lines, but there are a lot of areas where it will be years before new lines are installed, so there is still a lot of power line carrier systems in use. (link is to a PDF)
Joined
·
44 Posts
:batman:
Joined
·
2,963 Posts
Thing-a-ma-jigs ! or Do dads !What are these round things hanging in substations called ?
![]()
Joined
·
714 Posts
skinnamarinkydinkydink skinamarinky Doo
the economics professor in back knows a widget when he sees one
Joined
·
17,035 Posts
So I ran across a bit about line traps the other day that explained one of their uses:
In medium-voltage generation and distribution you have a type of protection called "differential relaying." Y'all that have been heavily involved in arc-flash studies are likely familiar with it, because it's a really common and effective method of fault detection. It works on the same principal as a GFCI: It knows how much and what type of current should be flowing in different parts of a system, and it compares those parts to make sure they add up mathematically. If there's current missing or flowing the wrong direction, it knows there's a fault.
For short distances, you just place a bunch of CTs in different locations. For long distances you can't run CTs that far, so you hook them to a relay on each end, and you let the relays talk to each other. This is called a "pilot wire" setup. For short pilot wires of a couple miles or less, we either run a copper pair or used a leased BANA phone line between the relays.
But apparently in transmission this is really cost prohibitive because a transmission line runs for hundreds of miles, so what they're doing is actually using the line itself as the pilot-wire to communicate from relay-to-relay and the line-traps are how they tie that signal in. And the cost of the line-trap itself is less than it would be to run a separate copper pair all that distance.
In medium-voltage generation and distribution you have a type of protection called "differential relaying." Y'all that have been heavily involved in arc-flash studies are likely familiar with it, because it's a really common and effective method of fault detection. It works on the same principal as a GFCI: It knows how much and what type of current should be flowing in different parts of a system, and it compares those parts to make sure they add up mathematically. If there's current missing or flowing the wrong direction, it knows there's a fault.
For short distances, you just place a bunch of CTs in different locations. For long distances you can't run CTs that far, so you hook them to a relay on each end, and you let the relays talk to each other. This is called a "pilot wire" setup. For short pilot wires of a couple miles or less, we either run a copper pair or used a leased BANA phone line between the relays.
But apparently in transmission this is really cost prohibitive because a transmission line runs for hundreds of miles, so what they're doing is actually using the line itself as the pilot-wire to communicate from relay-to-relay and the line-traps are how they tie that signal in. And the cost of the line-trap itself is less than it would be to run a separate copper pair all that distance.
1 - 20 of 27 Posts
