Repairing Underground Power Cables Is Nearly Impossible

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I never even considered high voltage lines underground... literally next to ground! I love engineering problems like this. Liquid nitrogen to hold back pressured oil? What a fascinating problem to work on. Thank you for sharing this story.

Singapore has a rather interesting (though experimental) solution for this, instead of buried lines that need to be dug up each time for repairs and modifications, a huge tunnel is dug (similar to train/vehicle tunnels so they can be easily accessed even by humans and machines), the lines are laid inside the tunnel which can be easily accessed without any digging up, while still having the benefits of not being exposed to weather

Engineers: "We invented new cool technology!" Also engineers: "..And now we have to invent 20 other new technologies to maintain it"

I work for lane construction company in Austin, I love every second of this guy's videos, makes me feel less alone in this large construction world. We're important but some ppl don't realize. This man is doing good work love this guy

When you got to having to open the pipe, first thing that came to mind was 'freeze seals'. We used both LN2 and Freon-based freeze-seals during maintenance outages at power plants to avoid having to completely drain key systems. Works great with water since water expands when it forms ice. Didn't know you could do that with oil, learned something new today. Thanks. :)

I work for a utility in the Northeast and we did some work like that on a 115 kV line that travels underneath the city. Very interesting work especially when you consider that the cable is insulated with paper and oil. Solid dielectric cable is quite a bit less labor intensive. If you feel like continuing on in this electrical infrastructure series, maybe a video about how the cable is constructed would be interesting to your viewers. Especially the differences between oil-filled cable, pilc cable, and solid dielectric cable.

I was working for LADWP when this line was installed, knew most of those working on the line. It ran close to my house so I would visit with them when I could. I also worked for the Generation section and was on the startup crew for Scattergood Unit 3 which this line was built for. Great video.

I'm a graphic designer & illustrator with no business getting my nose into this side of youtube but I find my self completely enamored with all of this complex engineering, I'm speechless and in awe of the great minds that created all of this, literally you guys keep the modern world together, and this video is magnificent, thanks for the effort of making it look so simple for us simpler folks ❤️❤️❤️

When I lived in Denver we built a high voltage channel. It was the smartest engineering I have ever seen. We dug a trench and placed a metal tube that was coated in a really thick non conductive poly liner. Workers could walk through the tunnel and there was even a track system for a power feed system to run new power lines through it. The power lines were mounted to the sides of the chamber with an ingenious clamping system and the system was built so they never had to dig it up because they could inspect and even change out the mains without ever disturbing anyone.

Literally after the first Practical Engineering video I saw, I wanted to be an engineer. I've always loved science, maths etc.. But Grady, you've set me on my true path. I will never be able to thank you enough!

Practical Engineering and Mentour Pilot are possibly the two greatest channels on youtube. Thank you so much for your scientific insights, educated tips, fascinating stories and general wisdom you spill among us.

I went to school for electrical engineering with a focus in utility technologies. I currently work for one of the largest electrical utilities in the north east (US). I have to applaud this video!! Your description and delivery of electrical infrastructure was incredibly impressive. Too often when people try to explain things with simplicity people either in accurately describe it or leave out key/fundamental information. Not only was your description simple for ordinary folks to understand it perfectly described the principles. Bravo!!! Lastly I recently found your page and have watched around a dozen videos. Your content, research and delivery is nothing short of phenomenal. I LOVE your videos. Clear concise and loaded with interesting information presented in a attention grabbing format. Thanks for your work! I’ll be a lifetime subscriber for sure

There’s always this moment, usually gradual, but a moment where channels on YouTube seem to cross a threshold, I never notice until maybe 2 or 3 vids after but I realize that the creator has hit a point where each video just feels like a massive jump in quality, as if they’ve figured out how to put more than 100% of their effort into every video they make, and each one just blows me away. I’m very sure that Practical Engineering is far past that threshold now and I didn’t have a clue until right now. I can’t wait to be blown away again!

As a water engineer I’ve come across these oil filled electrical cables a number of times. The asset owners have always been incredibly nervous about us working near these lines and now I know why! Thanks for the awesome vids, very informative.

One of my favorite things I learned about it my engineering classes was time-domain reflectometry! I think its really fascinating how you can send a pulse down a conductor and receive the reflection to determine roughly where a break is. Its one of the things I actually still think about often when I hear of an outage somewhere. I think "cool, I know how they might actually find the fault!" Not saying I was actually any good at it in school, just thought the concept was really neat.

I love watching everything you produce. Your passion for engineering is contagious and your ability to explain in simply terms is a credit to your understanding…!

Heh, weird to come across this on YouTube - I'm an electrical engineer with expertise in HV cables, and I performed a forensic analysis on a fault on this particular circuit in the early 2000s. I have to say you did a decent job describing the story and offering the world a bit of insight into strange and esoteric business of high voltage cables.

I designed a moderately elaborate earth retention system with many ground anchors close to a pipe-type cable (and several high-voltage tower foundations) several years back. The record drawings furnished by the utility (our client) only indicated an oil-filled steel pipe with the conductor details omitted. Trying to guess how that would work, I thought that the oil itself might be the conductor and that the large cross-sectional area of the oil is what kept the resistance low. Thanks for helping to explain how they actually are constructed and are designed to function.

@13:15 And thank you Grady for yet another great production. I have been watching your presentations for years and you never fail to amaze me with all the nuances found withing civil engineering. You are a great Youtuber. Keep it up!