Is it time to seriously consider burying power lines? 2

[Mbrooke]

I'm starting to get the epiphany that it is no longer cost practical to keep power lines above ground. Case in point- storm rolled through the North East during the night. Eversource Connecticut alone had 85,000+ without power and currently about 61,000. 26,000 for Central Hudson and Gas. 10s of thousands in National Grid territory. School buses driving over power lines, people trapped in homes, outages expected to last 3 days.

https://outagemap.eversource.com/external/default.html

https://outagemap.ny.nationalgridus.com/

https://outagemap.ma.nationalgridus.com/

https://stormcentral.cenhud.com/

Even Con Ed has them in their over head network but not to the extent its neighbors do:

https://apps.coned.com/stormcenter/external/default.html

Oh, the school kids:

https://www.wfsb.com/news/school-bu...cle_3b973ac4-fc9b-11e9-97bb-47a18a7356d4.html

Normally I wouldn't blink. But this is now happening every month it seems. Just two weeks ago the same thing happened across the north east. Prior to that micro bursts. Every winter an ice storm. Random Tornadoes. When I was younger it was just a few thousand customers and few hours until power restored. Now its 100,000 and close to a week without power.

Then look at PG&E. Texas. Middle America. I keep seeing a trend where distribution infrastructure is destroyed on a multi state level in just a few hours.

There is also the safety aspect of people driving over live wires, becoming tangled in them, people handling them during storm cleanup (no one takes the warnings seriously around here), attacking line crews and even folks taking the copper primary for scrap because people (and even police) assume them to be line workers in their T-shirts and white pickup trucks. Stores throwing out tens of thousands in food. Lost business. Fights at the gas pump. CO poisonings are another biggy- to this day people still think running a generator in doors with a window cracked is perfectly safe.

 

[catserveng]

Copperweld is a trade name for bimetallic wire,

https://www.copperweld.com/

Their copper clad steel cable is used by a number of utilities, some additional info if you want,

https://compow.com/manufacturers/copperweld

Here is a link from SCE with some talking points about undergrounding utility lines,

https://www1.sce.com/wps/wcm/connec...+in+progress/trtp/answers+to+common+questions

Actually working on a project where we will relocate an existing underground service at 66kV and bring it back to overhead, the local ground conditions have made keeping the circuit in service a problem, but as of now we are in the fourth year of trying to get this done, mostly permitting and contract issues.

MikeL.

 

[Mbrooke]

@catserveng: IS this in an earthquake region by chance? I know during the Christchurch earthquake they lost of a lot of underground feeders years back. They now make sure at least one subtransmission supply is overhead.

 

[cuky2000]

The main issues to convert existing infrastructures OH to UG are cost and reliability.
Although those are challenger conflicting tasks, I believe some upgrade conversion from OH to UG could be justified in vulnerable areas. However, I am not sure if it is feasible to change the entire T&D system in our lifetime.
Below are a couple of excerpts from the Edison Electric Institute study of the costs of undergrounding overhead power lines.

1}COST: With estimated costs to underground an entire electric utility in the billions of dollars, the impact to utility customers could result in their utility bill doubling.

1}RELIABILITY:it is important to remember than repairs to underground facility outages are often more complex and time-consuming and such facilities are more costly to upgrade and replace. And as recent experiences with Hurricane Sandy demonstrate, underground facilities are very vulnerable to flooding and water damage.

 

[itsmoked]

Mbrooke; If there is still time how about you correctly spell "burying" in the title? Bottom right corner, hit EDIT and fix it. Otherwise a year from now this thread gets really hard to find because people search for it with the correct spelling.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[bridgebuster]

That's Manhattan. In the other boroughs it's mainly above ground.

 

[Mbrooke]

Bronx, Brooklyn and Queens are predominately underground. And where there is overhead, half of it is only LV.

Anyone know of the bills in Europe?

Edit: I can't edit the original title.

 

[itsmoked]

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

The next option is to red flag one of your posts and ask the moderator to edit your title. And this one, and Keith's.
Keith: burry, from the verb "to burrow". grin

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[itsmoked]

Bill; Don't you mmean redd flagg itt?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

Issue #1: High winds bringing trees across lines.
Issue #2: Flooding of underground installations.
Issue #3: Hurricane, High winds and flooding. Will we gain as much as we had hoped? would the circuits now lost to falling trees possible be lost to flooding if they had been underground?

In our rural area, the cost adder for underground would be the cost of one single conductor cable. The rental for the eight wheeled articulated tractor and the cable plow would probably be much less than the cost of poles and hardware.
Our circuits, (25/14.4 kV), are single wire with a ground return. There is a grounding electrode at each transformer and the neutral is carried one span back and a second grounding electrode installed.



Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Mbrooke]

There is no edit button present anymore in the first post. I think that it would be obvious, that at some point the edit feature expires.

 

[Mbrooke]

@waross: I think underground could be really cheapened. Whats to stop 3 single conductors cables on the main road and one single conductor down the side streets?

I know Con Edison and United illuminating will run aerial bundle for miles on an overhead circuit. What difference would it make if buried?

 

[cuky2000]

The history of undergrounding in NYC is no new and may not be representative of other parts of the country.
Back in 2013 the estimated cost to convert OH to UG feeders in the 5 Boroughs of NYC was $42.9 billion. Con Edison’s entire capital investment budget for all its system-wide infrastructure improvements is approximately $1.5 billion annually. The analysis also indicates these costs would translate into a significant increase in the typical residential customer bill.
_{PS: The miles of OH in the 5 boroughs of NYC are: Bronx 2,667 mi (20%), Brooklyn 3,538 mi(12%), Manhattan 0 mi (all UG), Queens 6,968 mi (22%) and Staten Island 7,140 mi (72%).}

 

[Mbrooke]

Examples of ABC in UI's territory:

 

[Mbrooke]

Manhattan 0 mi (all UG)

Well, I beg to differ

On East 16th st there is a small stretch of overhead line behind the East 13th st generating plant.

 

[waross]

Mbrooke; All of the cables that are identified by the red arrows are messenger cables for insulated power conductors, telephone and or cable TV.
As for three buried singe conductors, That will cause impedance matching issues, and excessive reactive voltage drop.
There are three conductor cables suitable for direct burial.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Mbrooke]

@Waross: they are 15kv cables. This I know for a fact and hence why I included picture #2 and 3 where the cables transition over to a gang switch and then bare wire. Con ED and UI do this all the time. They will run several MV ABC cables (from the substation) going up to 8 miles to feed an area. Its an elegant approach to getting more MWs out of a wooden pole and more reliable. Often when a tree takes down the bare wires the bundle keeps power on for the other circuits down stream. If it can be done overhead why not underground?

 

[waross]

Thanks for the explanation.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[cuky2000]

Mbrooke,

Due to an Ordinance dated back to the 1800s, In Manhattan, the fraction of OH lines are virtually negligible. If there is any power pole in operation in Manhattan this is considered against the local city ordinance.

According to the NYC Historian of power and spokesmen from the power and telco companies, the following are published information associated with pole ownership in Manhattan: ConEd: [highlight #FCE94F]does not own any pole.[/highlight] Verizon: only own 7 poles.

See below for more details and background info on this matter.

 

[3DDave]

I wonder, particularly for city centers, how much this is influenced by the presence of existing steam tunnels.