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There is nowhere in the world that power lines are put underground unless there is a reason they can't go above ground: dense urban area, unable to secure a rig
by eigenvector 8y ago
There is nowhere in the world that power lines are put underground unless there is a reason they can't go above ground: dense urban area, unable to secure a right-of-way, crossing another piece of linear infrastructure like a highway, etc.. It's way more expensive to go underground, it causes technical challenges at high voltage necessitating additional, expensive infrastructure like capacitor banks and point-on-wave energization control and it's harder and more costly to inspect, test and maintain. Insulated power cables are subject to third-party intrusion (technical jargon for people digging and hitting them), water and contaminant ingress, and it's hard to determine their condition without taking them out of service and using specialized equipment for testing. Even then, it's very hard to pinpoint the exact location of degradation and you have to dig to access it. Splicing them requires very highly trained workers and if the work isn't done right it fails in the middle of the night 5 years later.
There is more underground distribution (medium voltage) in Europe because cities are denser and older and there's less space for overhead lines. Transmission (high voltage) is still 99% above ground.
I'm a power systems engineer and I have no idea what 'rest of the world' you're talking about. The first choice for cost, reliability and ease of maintenance is always overhead.
- mmt 8y ago> There is more underground distribution (medium voltage) in Europe because cities are denser and older and there's less space for overhead lines. Do you know if the existence of other relatively large, underground facilities, namely subway railways, is a factor? Is it a common/reasonable practice to use a rail tunnel for (non-rail) power distribution? I can imagine it would the advantage of not having to dig for inspectin/maintenance but a disadvantage of needing to coordinate with rail operation instead.
- nikonyrh 8y agoFinland is moving quite a lot of power lines underground especially in the middle of forests, because falling trees are a problem during a seasonal storm[0]. I'm not sure how this cheaper than cutting down the trees though. Sadly most of the information is in Finnish. >In reality, the difference in the status of power lines between Canada and Finland is not so clear-cut. As things stand now, 11% of power lines in Québec (my province of Canada) are buried, while this number is approximately 42% in Finland. The main difference though, is that Finland has an active strategy to increase this number to 65% by 2029. Helen, the energy company for Helsinki, already operates a power network buried at 97,7%. The new law seems to demand that power outages must not be longer than 6 hours within cities or 36 hours on rural areas[1][2]. [0] https://www.tys.fi/power-lines-buried-finland-not-canada/ https://www.tys.fi/power-lines-buried-finland-not-canada/ [1] https://yle.fi/uutiset/3-6927938 https://yle.fi/uutiset/3-6927938 [2] https://www.tekniikkatalous.fi/tekniikka/katkoton-sahko-vie-kaapelit-maan-alle-tiedossa-miljardilaskut-6210295 https://www.tekniikkatalous.fi/tekniikka/katkoton-sahko-vie-...