That is pretty impressive insulation given how far a 20kv spark will jump. Fascinating info about the slightly conductive insulation layer. Thanks for another great video, and in 4K!
About 3 years ago our street lost power; 22 homes with underground power. The problem was traced to the underground power cable near the #1 house on the street. We (residents) thought it was fault proof having underground power. It took the power company almost the whole day to find the problem. They brought in a generator to give us all power while they dug a deep hole and spliced the bad cable. It was late into the night when we had our power back to normal and they could remove their generator. Those guys worked diligently.
@@fosarvian It actually happened twice, about 12 years apart. We bought a small gasoline generator at a yard sale 20 years ago. It had enough power for watching the TV but couldn't run the forced air heater. About 5 years ago we bought a duel fuel (gasoline or propane) generator so we could run our house heater and lights. Noisy. Ah, well, at least it's not snowing . . .
If you think 1 day is a long time hear my story. When I was a kid we lost power and they started digging. They’ve been fixing the problem for days, maybe weeks. My grandma brought a block of paraffin and we made candles by melting it and sticking rope into it. We’ve made and used quite a few candles. I was not happy with the situation at the time but I’ve learned something new and have a memory for life.
Reminds me of an AvE video.. no face no bullshit just the nerdy facts. Earned yourself a subscriber. I’d listen to explanations on this stuff any day please post more
Absolutely interesting! I didn't expect that much interesting knowledge and information to learn about this topic. So i am glad i watched it. Really clear, complete and helpfull.
Went to school for electronics so I understand the principles in your explanation. Other than the voltages in CRTs (yea I am old) 480 in years of maintance is the highest I worked with. This transmission high voltage is a different animal. Enjoy your videos, you do a great job of explaining things. Thank you.
Another thing the semicon layer in the cable over the conductor prevents is corona discharge in any air voids, as this would create ozone that would rot the cable from the inside. This is due to the dielectric constant of air being barely over that of a vacuum and a small fraction of the dielectric constant of the XLPE/EPR insulation. This means that the electric field in any voids will be comparably higher, and probably high enough to get breakdown. Transformers are in oil baths or vacuum impregnated with transformer resin for the same reason (besides the cooling benefits of oil in wet tank transformers, of course). Also, flux normally refers to the magnetic field of something, not the electric field.
International undersea internet cables are built much the same. They have optical fibres down the middle, a bit less power conductor for the optical amplifiers along the way, and about the same amount of white polythene insulation for 10kVdc 25 years life, plus a metal tape outer layer to keep sharks and worms out. In shallow water, there are added various amounts and sizes of armour wires, to avoid abrasion and damage from fishing, landslides, ship anchors etc. I wish we had so few external risk factors as this power cable! But if somebody goes through it with a digger, the power cables make a much louder bang.
This is a pretty good explanation. I would like the opportunity to refine your explanation of cable failure as it pertains to Partial Discharge and insulation shield punctures.
Awesome video! We just used this on a solar field we are finishing up! Your substation video was awesome and helpful also! So now i’m a subscriber! Thanks a lot!
Do you have to de-rate this cable ampacity when using it in conduit underground? If so, do you use the NEC or is there a special wind farm standard for underground cables?
That was fascinating... has me all thinking about what it takes to keep that crackling high voltage/current contained within that cable. Thanks for sharing, SpeedFreakLS1. If you do happen to make a 2-day long video about this subject, I'll definitely watch that, too. lol ;-)
@@apollorobb I looked up Faraday's law but it only talks about magnetic flux. When he describes flux in the video, it seems more like he's referring to the electric field strength so I'm not quite sure either.
From what I've read, the partially conductive layer is there to avoid partial discharge. Its evening out the distribution of the electric field. Similar to corona rings avoiding spikes in the field strength and discharge to air.
@@Berkeloid0 he is indeed talking about electric field. I think it is like that blue corona around a hv loaded conductor in air. Something like that plays a role inside the insulationmaterial as well as in air, i think. But indeed is flux a strange word for that effect, at least for us who know the word only referring to magnitic fields.
@@robson6285 electric flux seems to be a valid term. Its the strength of the electric field per area (field line density). But im not sure if we called it that way in physics class
The electric flux is the number of electric field lines passing through an area. Formally, flux is the dot product of a vector field with an area vector. This definition mathematically handles the general case when the electric field lines are not perpendicular to the area they are passing through. A super useful application of this dot product definition of flux in electrostatics is Gauss's Law. The total flux passing through a surface that completely surrounds a volume tells you the amount of charge contained within.
I have a question is there a type of non contact tester for medium voltage cable like this ...also does the hex bolt head in the insulated plug become energized when the wire is energized? Or does it remain with no voltage on it.
Great questions! There are non contact testers out there. One is a Salisbury 4744, for URD cable. On the hex head on the insulating plug, it's insulated from the other end where the stud is. It may build up a charge, but does not have any voltage on it.
I am picturing technicians running around in steel fabrication shops with little nets catching the soot from the welder's oxy/acetylene torches, a la SpongeBob catching jelly fish.
Why would a neutral be needed in a 35kv transmission line? What use would it be? No loads are running off 19kv or whatever it was line to neutral. Is it there just to have a grounded system for the power transmission?
He sort of explained it. Phase to ground is 19,900. You get 35kv phase to phase because each phase is offset from the next by 120deg. So 19,900 x 1.73 (square root of 3) is approx 35kv. The generators and transformers are churning out 19,900 per phase. When you calculate the 120deg offset, the voltage from phase to phase will read 35kv.
I've seen a similar cable, or this cable about 4 years ago in technical school, and the told us something you didn't say (or I probably didn't hear), this cable acts as a capacitor, and if you have to work on it, after shutting the electricity off, you have to ground the conductor, or you will probably get killed
Actually, due to the skin effect, it would be the stranded cable that would be the better conductor rather than the solid. That's why tri-rated cables come in hairline wire flex strands.
@@spdfreakls1 Yeahh thats unfortunate but I get it.. Those were awesome vids man!! Im a grad with a major utility and am currently based at a 400kV HVDC station and those vids were super informative!! Perhaps we can keep in touch on other social media platforms..?
@@JBernhard72 "flux" is a very fuzzy term to describe the induction of eddy currents. I thought eddy currents are induced by varying magnetic fields. where did the magnetic fields come from.
I may have misunderstood, or it may be different in different countries, but ..... Is the HV not generated in Delta format? This would mean there is no real Neutral. It is my understanding that the neutral is the Star point and only exists on LV (415/240 in the UK) and is connected to earth at the star point! Obviously this then "anchors" earth potential to neutral on LV and keeps the HV relative to this! I was a tad confused when you talked about Flux. Magnetic flux runs parallel with the flow of current .... this is totally different from the Electric Field which runs at right angles to this! ;0)
This would be a 19,920V/34,500V grounded Y system so there is a true neutral in the system. The neutrals in this case carry the charging current of the cables, as the main load is 3 wire delta. USA/Canadian distribution systems use a lot of Y connected systems for their primaries (2,400V/4,160V, 4,800V/8,310V, 7,200V/12,470V, 7,620V/13,200V, 7,960V/13,800V, 14,400V/24,940V and 19,920V/34,500V are the normal ones, but there are others). Primary in this case refers to what is connected to the primaries of distribution transformers, which are what feeds angry pixies to the end consumer.
@@randacnam7321 They would be Extremely angry pixies in my book! ;0) Primary does have a different meaning in distribution systems. Here in the UK Primary substations take the distribution voltage (400KV Delta) and drop it to various intermediate voltages to distribute to "normal" substations with it ending up at 11KV to 415/240 (Delta Star configuration). The Star point of the 415/240V is the neutral and is also taken to the body of earth via mats and rods! This allows earth fault detectors to pinpoint faults on the HV and allow remote switching to get people on asap!
Agreed. I'm new to video stuff. This was my first time using a tripod. When i got the camera too close it blocked the light. I'm slowly figuring this stuff out!
@@spdfreakls1 pretty accurate description of cable structure. I'd have phrased a couple things a little differently. I'd be curious to chat with you about your thoughts on cable testing.
I just started working in the industry after years in oil and gas. These videos are helping tremendously!!
That is pretty impressive insulation given how far a 20kv spark will jump. Fascinating info about the slightly conductive insulation layer. Thanks for another great video, and in 4K!
About 3 years ago our street lost power; 22 homes with underground power. The problem was traced to the underground power cable near the #1 house on the street. We (residents) thought it was fault proof having underground power. It took the power company almost the whole day to find the problem. They brought in a generator to give us all power while they dug a deep hole and spliced the bad cable. It was late into the night when we had our power back to normal and they could remove their generator. Those guys worked diligently.
That’s actually not bad.
@@fosarvian It actually happened twice, about 12 years apart. We bought a small gasoline generator at a yard sale 20 years ago. It had enough power for watching the TV but couldn't run the forced air heater. About 5 years ago we bought a duel fuel (gasoline or propane) generator so we could run our house heater and lights. Noisy. Ah, well, at least it's not snowing . . .
The guy using the equipment to do the " Fault Locate " must have been new for them to take that long to find where the Fault was ! !
If you think 1 day is a long time hear my story. When I was a kid we lost power and they started digging. They’ve been fixing the problem for days, maybe weeks. My grandma brought a block of paraffin and we made candles by melting it and sticking rope into it. We’ve made and used quite a few candles. I was not happy with the situation at the time but I’ve learned something new and have a memory for life.
@@AI-xi4jk Making candles is a good thing to learn. I also learned to do that back in the 1950's. Kids love to learn how to do useful things.
I actually learned something on UA-cam, didn't think that day would come :)
Especially your explanation on the concentric Neutral was nice.
Reminds me of an AvE video.. no face no bullshit just the nerdy facts. Earned yourself a subscriber. I’d listen to explanations on this stuff any day please post more
AvE has way more sayings and is funnier than me. I almost did say "Focus you f&%k!" Lol
@@spdfreakls1 I heard you say it, and I don't even watch Ave anymore, but he infected me with Canadian Camera Hatred! Lol
Absolutely interesting! I didn't expect that much interesting knowledge and information to learn about this topic. So i am glad i watched it. Really clear, complete and helpfull.
Very informative. That’s why I like YT - you can learn loads even if you’re not remotely connected (no pun intended!) with the trade concerned! 👍🏻
Great explanation of underground cable.
Who would have thought a small piece of cable could be so interesting! Well done sir ! And thanks
Until you picked it up, I thought you just printed out a photo. Love learning about this stuff.
Got me too.
Videos like this one are what make UA-cam great. Informative and to the point. Thanks for the hard work.
Went to school for electronics so I understand the principles in your explanation. Other than the voltages in CRTs (yea I am old) 480 in years of maintance is the highest I worked with. This transmission high voltage is a different animal. Enjoy your videos, you do a great job of explaining things. Thank you.
Very good videos
What an absolutely brilliant educational video! You’re a great teacher.
Another thing the semicon layer in the cable over the conductor prevents is corona discharge in any air voids, as this would create ozone that would rot the cable from the inside. This is due to the dielectric constant of air being barely over that of a vacuum and a small fraction of the dielectric constant of the XLPE/EPR insulation. This means that the electric field in any voids will be comparably higher, and probably high enough to get breakdown. Transformers are in oil baths or vacuum impregnated with transformer resin for the same reason (besides the cooling benefits of oil in wet tank transformers, of course).
Also, flux normally refers to the magnetic field of something, not the electric field.
International undersea internet cables are built much the same. They have optical fibres down the middle, a bit less power conductor for the optical amplifiers along the way, and about the same amount of white polythene insulation for 10kVdc 25 years life, plus a metal tape outer layer to keep sharks and worms out. In shallow water, there are added various amounts and sizes of armour wires, to avoid abrasion and damage from fishing, landslides, ship anchors etc. I wish we had so few external risk factors as this power cable! But if somebody goes through it with a digger, the power cables make a much louder bang.
This is a pretty good explanation. I would like the opportunity to refine your explanation of cable failure as it pertains to Partial Discharge and insulation shield punctures.
Thanks for teaching tri-foiling. Useful on the job
Better explanation then my module, glad I saw this before my exam. 👍
Awesome video! We just used this on a solar field we are finishing up! Your substation video was awesome and helpful also! So now i’m a subscriber! Thanks a lot!
Do you have to de-rate this cable ampacity when using it in conduit underground? If so, do you use the NEC or is there a special wind farm standard for underground cables?
That was fascinating... has me all thinking about what it takes to keep that crackling high voltage/current contained within that cable.
Thanks for sharing, SpeedFreakLS1.
If you do happen to make a 2-day long video about this subject, I'll definitely watch that, too. lol ;-)
We run 345 mil 1/0(solid conductor) primary cable through pipe/conduit all the time. Definitely doesnt go in hard 90 degree bends of course.
When you talk about flux, I'm assuming you are referring to lines of magnetic flux?
Look up Faradays Law
@@apollorobb I looked up Faraday's law but it only talks about magnetic flux. When he describes flux in the video, it seems more like he's referring to the electric field strength so I'm not quite sure either.
From what I've read, the partially conductive layer is there to avoid partial discharge. Its evening out the distribution of the electric field. Similar to corona rings avoiding spikes in the field strength and discharge to air.
@@Berkeloid0 he is indeed talking about electric field. I think it is like that blue corona around a hv loaded conductor in air. Something like that plays a role inside the insulationmaterial as well as in air, i think. But indeed is flux a strange word for that effect, at least for us who know the word only referring to magnitic fields.
@@robson6285 electric flux seems to be a valid term. Its the strength of the electric field per area (field line density). But im not sure if we called it that way in physics class
Thank you so much for your labor. Wish all the best
Good explanation. I never thought there was so much into a high voltage cable. For me 110Vac is high voltage, I am more in the 12V and less world.
It can go up to 400kV. I have designed a 525kV HVDC and is quite fascinating
The electric flux is the number of electric field lines passing through an area. Formally, flux is the dot product of a vector field with an area vector. This definition mathematically handles the general case when the electric field lines are not perpendicular to the area they are passing through. A super useful application of this dot product definition of flux in electrostatics is Gauss's Law. The total flux passing through a surface that completely surrounds a volume tells you the amount of charge contained within.
In the middle of the cable cross section is the aluminum nerve
Good video. I install, splice, and terminate this stuff every day. Going on 30 years as a splicer/crew leader.
Nice! I may do a splice video in the future . We use 3M and Tyco splices mainly. What about you?
@@spdfreakls1 Same here
I've been selling it for 43 years. You are light years ahead of me as an installer. Splicing it looks sooooo tedious, there is no room for error.
Fun fact: the US Treasury loaned 14,700 tons of silver to make electromagnets that were used on the Manhattan project.
I have a question is there a type of non contact tester for medium voltage cable like this ...also does the hex bolt head in the insulated plug become energized when the wire is energized? Or does it remain with no voltage on it.
Great questions! There are non contact testers out there. One is a Salisbury 4744, for URD cable.
On the hex head on the insulating plug, it's insulated from the other end where the stud is. It may build up a charge, but does not have any voltage on it.
Also having stranded conductors eliminates skin effect. Probably not as important for typical 50/60Hz systems
I am picturing technicians running around in steel fabrication shops with little nets catching the soot from the welder's oxy/acetylene torches, a la SpongeBob catching jelly fish.
Exactly!!!
Why would a neutral be needed in a 35kv transmission line? What use would it be? No loads are running off 19kv or whatever it was line to neutral. Is it there just to have a grounded system for the power transmission?
Dielectric stress control and cable charging current.
Good video. I wanted to know if the high voltage was phase to phase, or phase to ground
He sort of explained it. Phase to ground is 19,900. You get 35kv phase to phase because each phase is offset from the next by 120deg. So 19,900 x 1.73 (square root of 3) is approx 35kv. The generators and transformers are churning out 19,900 per phase. When you calculate the 120deg offset, the voltage from phase to phase will read 35kv.
What’s the reason the concentric neutral isn’t aluminum?
Have you ever seen a 3 phase 34.5Kv circuit carried in a cable on a pole above ground rather than open conductor? Thank you for the video.
was that section cut on a deli slicer?
Haha close! A horizontal band saw set to cut only 1 inch per minuite to keep it smooth while held with a vice to keep it straight.
What you explain they the semi con should not have flags on it when cut
where are your videos about the 345 kv and 34 kv substation.
I am looking for them too! They are the best substation videos. I wanted to show them to my power systems class.
Thanks. This information is very useful.
Thanka for share verry interesting content
I've seen a similar cable, or this cable about 4 years ago in technical school, and the told us something you didn't say (or I probably didn't hear), this cable acts as a capacitor, and if you have to work on it, after shutting the electricity off, you have to ground the conductor, or you will probably get killed
Exactly right!
Actually, due to the skin effect, it would be the stranded cable that would be the better conductor rather than the solid. That's why tri-rated cables come in hairline wire flex strands.
So helpful, thank you!
Hey whatsup man! Hope all is well! What happened to your other videos? The sub ones, etc
I had to take them down due to an owner request. Very sad about it but i need to respect their wishes!
@@spdfreakls1 Yeahh thats unfortunate but I get it.. Those were awesome vids man!! Im a grad with a major utility and am currently based at a 400kV HVDC station and those vids were super informative!! Perhaps we can keep in touch on other social media platforms..?
@@mikevarela705 nice! Any way to share some videos of that DC yard? That would be awesome!!!!
@@spdfreakls1 Yeahh man forsure, you on IG or Twitter?
what you mean by flux, do you mean electric field or an induced magnetic field and why does it "bleed" ?
Electric fields... look up Eddy currents
@@JBernhard72 "flux" is a very fuzzy term to describe the induction of eddy currents. I thought eddy currents are induced by varying magnetic fields. where did the magnetic fields come from.
Great video. Thx!
I may have misunderstood, or it may be different in different countries, but .....
Is the HV not generated in Delta format? This would mean there is no real Neutral. It is my understanding that the neutral is the Star point and only exists on LV (415/240 in the UK) and is connected to earth at the star point! Obviously this then "anchors" earth potential to neutral on LV and keeps the HV relative to this!
I was a tad confused when you talked about Flux. Magnetic flux runs parallel with the flow of current .... this is totally different from the Electric Field which runs at right angles to this! ;0)
This would be a 19,920V/34,500V grounded Y system so there is a true neutral in the system. The neutrals in this case carry the charging current of the cables, as the main load is 3 wire delta.
USA/Canadian distribution systems use a lot of Y connected systems for their primaries (2,400V/4,160V, 4,800V/8,310V, 7,200V/12,470V, 7,620V/13,200V, 7,960V/13,800V, 14,400V/24,940V and 19,920V/34,500V are the normal ones, but there are others). Primary in this case refers to what is connected to the primaries of distribution transformers, which are what feeds angry pixies to the end consumer.
@@randacnam7321 They would be Extremely angry pixies in my book! ;0)
Primary does have a different meaning in distribution systems.
Here in the UK Primary substations take the distribution voltage (400KV Delta) and drop it to various intermediate voltages to distribute to "normal" substations with it ending up at 11KV to 415/240 (Delta Star configuration). The Star point of the 415/240V is the neutral and is also taken to the body of earth via mats and rods! This allows earth fault detectors to pinpoint faults on the HV and allow remote switching to get people on asap!
Very cool! Thanks
Great to Know Thanks
What happened to the serving plate layer? That's the only one I got right on the quiz!
😭😭😭
I enjoy your content
I wish he would have talked about electric trees and water trees in the insulation .
Well explained
Vary informative
👍👍
Looking for splicers? 😁
The sample slice is deceiving. That does not look big enough to be 1500kcmil. I sell 500, 600 and 750 and that doesn't look much bigger.
👈You doing electrical cable termination
👈watching this channel
Kinda wished you had a close up for most of the video.
Agreed. I'm new to video stuff. This was my first time using a tripod. When i got the camera too close it blocked the light. I'm slowly figuring this stuff out!
@@spdfreakls1 Thank you. I really appreciate the detailed explanation of this cut-away sample.
@@spdfreakls1 pretty accurate description of cable structure. I'd have phrased a couple things a little differently. I'd be curious to chat with you about your thoughts on cable testing.
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where do you see yourself in five years?
Drinking Tiger blood with Charlie Sheen.