To Bury or Not to Bury [Telecom]

From: "Tony Toews \\[MVP\\]"

> To: snipped-for-privacy@invalid.telecom.csail.mit.edu > Subject: Re: Technical Demo turns political 2/26/1909 [Telecom] > Message-ID: > > David Clayt> > >>>> It cost more initially, but in the long run they will be more >>>> reliable >>>> and generally beneficial to the community in many ways. >>>> >>> >>> How will underground cables be more reliable and generally >>> beneficial to >>> the community? >>> >>> >> Vehicles can't crash into power poles that aren't there, winds can't >> affect power lines that are underground, and the visual pollution of >> underground power distribution is limited to the access ports on the >> pavement. >> > > One newspaper report I just read stated that underground power > lines cost from 4 to > 10 times as much as overhead lines. > > I've also read reports that indicate trouble shooting and repairing > underground power > lines near the end of their life is very expensive. > > So I'd want to see some detailed cost estmates and real world > experiences before > agreeing that underground power lines are a "good thing". >

Last September, Hurricane Ike took out electricity to some 300K houses in in Kentucky. [A HURRICANE - in KENTUCKY! - some nine hundred miles from the Gulf of Mexico].

My house was out for nine days.

In January of this year, an ice storm took out power to some 700K houses here. I was out for eight days.

Our electric monopoly, long-ago privatized, said in September and repeated in January that it would cost ratepayers a million dollars a mile to bury the lines. Overhead lines were said to be one tenth of that. No mention was made of what it would cost to cut the damned trees that took out the lines both times.

-- The war on privilege will never end. Its next great campaign will be against the privileges of the underprivileged. H. L. Mencken

Reply to
Randall
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Power companies used to be aggressive to keep power lines clear of trees. Not so much anymore.

As to burying power lines, obviously individual lines to houses and lines to a block of houses can be buried. But is there a limit to the amount of voltage on a line that can economically be placed underground? I thought at one point higher voltages don't work so well underground.

I'll note that while in the city phone lines are buried, in the suburbs they're on poles.

Reply to
hancock4

On Sat, 07 Mar 2009 19:51:20 -0500, Randall wrote: .......

Overhead lines may be appropriate for third-world environments, but in the

21st Century you would think that we would have learned about their limitations by now.

As I said in another post, installing fibre with every underground power service would also update - and future-proof - that side of things at a very small incremental cost.

Given the way the global climate is going feral, it may be a very good idea to make as many "Essential Services" as resilient as possible - or have every home with their own power generator.

I wonder which option is the most cost-effective?

Reply to
David Clayton

there was a new line strung thru a national park in N Wales (UK) to get to a pump storage scheme a couple of decades back as part of the UK Grid.

so - it will be 400 kV......

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-- Regards

stephen snipped-for-privacy@xyzworld.com - replace xyz with ntl

Reply to
Stephen

About 15 (20?) years ago there was a public campaign in the city where I am to put a new major power interconnect underground rather than the original overhead, and it eventually went that way - so it can be done for HV.

My state recently started using a major undersea power feed (480 MW continuous capacity using DC with appropriate conversion at either end) from Tasmania where they have major hydro supplies - the cable feed power one way for peak use and in off-peak times base load power flows the other way to pump the water back up to provide more peak supply.

We also (apparently) have the "the worlds longest underground power link":

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Here's a Wikipedia link with some more general underground info:
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Reply to
David Clayton

When you buy a big power cable, it normally comes with several strands of fibre in the jacket to use for telemetry.

However - letting untrained telecomms engineers play with HV tends to increase your insurance costs :)

The National Grid in the UK invented a machine to crawl along [each] wire on a line of pylons and string a fibre cable - it turned out to be a very quick way to build a new telecomms backbone (at least compared to digging in a duct if the power line is already there).

Note you can get composite earth cable with embedded fibres now, which is going to last longer.

That only pushes the "critical service" back to whatever fuel you burn.

I suspect it depends on local weather and terrain.

My favorites example is Austria - where some power cables go over the mountains rather than following the valleys.

Reply to
Stephen

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