strobes on high tension lines

[dqdave1]

I know this thread is way out there but people on this site have a vast knowledge of "everything", so here goes.

I had a job with backhoe and was working near some electric high tension lines. During the day I noticed three obects on high tension lines ( one object on three of the four lines) I was curious but in sunlight it was hard to tell what they were. I finished the job late and as I was leaving the site I noticed the opbects were strobe lights that were flashing. I have never seen these before and owner of property said he just noticed them a few months ago. He had never seen them flashing till that night. Anyone know what these are for?

 

[Robert_in_NY]

Was there an airport near by?

 

[MrJimi]

They are for Planes like the orange balls
Orange balls here

 

[jsborn]

Probably one of two things.

1. Fault and or load indicators that start flashing when a preset load level is reached so the utility workers can find and monitor overloading conditions.

2. If you were close by an airport or helicopter port they may be just what they look like strobe lights for pilot warning.

Both of these are in use here in Ga and after 35 years of working for Ga. Power Co. I have seen all of them I care to see.

 

[dqdave1]

No airports anywhere close; they were actually surrounded by trees. Load indacators is what I thought but thought someone here may know exactly what they are for.

 

[RonMar]

Aircraft obstruction warning lights. They are usually placed on the towers though. Was this wire spanning a canyon or river/valley? They typically flash 24/7, just at a different intensity between day and night. The flash pattern for towers with wires strung between them involves 3 lights placed vertically on the tower. The sequence is middle, top, bottom. This indicates that there are suspended wires between the towers flashing this sequence. We had them at my last LORAN station in Eastern Washington. We had four 700' towers with the wire antenna strung in between them. We had a lot of crop dusters in that area so the lighting pattern was mainly for them as most pilots don't fly that low, unless there is a canyon or river valley underneath the wires.

 

[jsborn]

No airports anywhere close; they were actually surrounded by trees. Load indacators is what I thought but thought someone here may know exactly what they are for.

You are correct

 

[HC-80]

I learn something new everyday. This site is awesome!

 

[dqdave1]

THere is another set of high tension wires about 100 yards from these and no lights on them. They do not flash all the time. Since I was at this job site, I pass by quite a bit to and from other job sites; since that night, they have not been flashing. The strobes are pointed to the ground; that is they have shields around them to reflect all light to the ground. No canyons etc. I would assume they have a circuit in them that when voltage is high enough, they do not flash; when voltage drops , they are activated.
JSborn; Thanks, I knew someone would actually know what they were. These are the first ones I saw and now I look at high tension lines , looking for them. I would not want to install them; voltage has to be very high on those lines; these are transmission lines goeing to substations, not your 7200 or whatever distribution lines along roadways.

 

[Savagepike]

Our transmission lines in this area range from 100-500kVA depending on the generation point. I know I don't want to personally be testing the load on a 500,000 volt line up close. That's why they're strung up with 10' insulators due to the ability of an open air fault to happen. I've seen a 8' phase to phase fault happen in a hurricane, very scary. Great invention whoever came up with those LIs.

 

[glmf]

Yes having worked at our local utility for a few years the power of these high voltage lines is impressive. In our 345KV switchyard, the disconnects are manually opened or closed. I would say that 8ft is about right for the distance that the arc jumps when you are operating the crank. Its 20ft above your head, but still impressive every time I do it, especially on a damp evening! Lots of fun, take 550 gallons of heavy oil a minute, and convert it to electricity and you get some power,,,,

 

[Cap-n-Cray]

High voltage is fun

DANGER HIGH VOLTAGE

Cary

 

[jsborn]

Most of those indicators can be installed either by hand or with insulated sticks from the ground. They look at the current on the line more than the voltage but either way they are used mostly for load information.

The company I worked for did maintenance on 230 and 500 KV lines using the Bare hand method when possible. This is a method of attaching yourself to the live line and doing your work while the circuit is still energized . It does take some training and is kind of scary at times but it also makes the work quicker and better for the customers.

I have been energized at 500 KV a few times in my career with very few lasting affects I think but that is my opinion not necessarily my wife's.