Posted by EXT on July 30, 2010, 2:24 pm
> A lot of the people wanted underground lines so they could have trees
> without fighting the power company, but in a round about way, they are
> going to have to have those trees removed to replace the underground lines
> in 20 years. So there is no way to win.
Around here often the underground installation companies install natural gas
pipes in a unique way. To install natural gas lines they use an air powered
"torpedo" which will drag a cable underground over about 50 to 100 feet at
a time. This cable is used to pull a cone to enlarge the tunnel and then
drag a plastic gas distribution pipe without tearing up the entire route
allowing them to go under trees. I am sure the same technology can be used
to pull wires or conduit for wires.
Posted by Michael B on August 1, 2010, 12:18 am
> I was watching one of those discovery channel shows talking about the
> crumbling of American infrastructure. One of the things they covered was the
> power reliability problems in Deerfield IL. To the point that they sued the
> power company. They talked about old power lines being the problem, and
> showed pictures of old above ground poles. But I really think they missed
> the actual problem with the system in Deerfield.
> The primary cause of the outages in Deerfield is the underground part of the
> system. Not the aboveground part.
> Deerfield is on of those communities that went to the expense of having most
> of the wiring put underground in a lot of the developments. It was direct
> burial installation. The problem is, it is over 20 years since the power
> lines were installed, and they are reaching end of life. The only answer to
> fixing it is, you have to completely rip everything out and replace it.
> There power company has already replaced several miles of underground line,
> but that is just a fraction of what is there. If they do replace all of the
> lines, it will keep everything running for about another 20 years, then they
> rill have to repeat it all again.
> End of life for overhead lines is 50 to 60 years. Some are still in service
> long after that in dry areas. The industry is finding out that the end of
> life for buried lines seems to be 20 to 25 years.
> Some places I had read about were even more depressing. They stated that it
> would take them 20 years to replace all the lines. Which, given the 20 year
> lifespan, means that when they finish, they will instantly start back at the
> beginning again. Or basically, continuous perpetual replacement of the power
> system.
> From what I have seen, power companies have seem to accept that fact,
> because they are putting the power lines in conduit for most of the newer
> installations. That allows them to pull the lines and replace them without
> having to dig up the land in-between. But the idea of pulling and replacing
> everything every 20 years is not hopeful in regard to power prices. Because
> every customer pays for that work with their power bill.
> And it will also mean more scheduled outages, because you can't relplace
> them while the system is live, so when you pull the wires and replace them,
> everyone is out of juice.
> And that doesn't help the countless places that have already had their lines
> directly buried over the last 20 to 30+ years. All those communities are on
> a runaway train headed right for endless power problems, and major
> excavation and replacement of their systems.
> A lot of the people wanted underground lines so they could have trees
> without fighting the power company, but in a round about way, they are going
> to have to have those trees removed to replace the underground lines in 20
> years. So there is no way to win.
> With all the communities pushing for underground lines, are we, as a country
> setting are selves up for a lot of power related headaches in the future?
This is one of the more exhaustive studies.
www.scc.virginia.gov/comm/reports/report_hjr153.pdf
Posted by N9WOS on August 1, 2010, 1:44 am
This is one of the more exhaustive studies.
www.scc.virginia.gov/comm/reports/report_hjr153.pdf
>Early underground residential circuits failed at a much higher rate than
>expected,
>but experts now believe that new underground circuits will last at least 30
>years,
>while overhead circuits will last 40 years or greater.
Why doesn't that statement instill confidence? What about all that cable
that is already in the ground? The "experts" were surprised by the much
higher than expected failure rate of first gen cables. But we should
believe them now? With all the worthless expert "opinion" and "consensus"
that we have seen over the years, you will just have to put me on the
skeptic side of things.
Put then in the ground, cross your fingers, and pray...
>The potential benefits, both to the utilities and to the economy, resulting
>from the >elimination of tree trimming maintenance,
I have news for them. When you have direct burial, or conduit buried cable,
you still have to keep large growth/deep rooted trees from establishing
themselves. The roots will disturb the underground line. When a tree blows
over, if it's roots are around the line, then it will be ripped out with the
tree. A conduit won't help any.
Posted by Josepi on August 1, 2010, 2:05 am
Our 14Kv cables are installed in duct banks with concrete around them for
major runs down streets. backyards get direct burial cables and this could
be a problem.
I have news for them. When you have direct burial, or conduit buried cable,
you still have to keep large growth/deep rooted trees from establishing
themselves. The roots will disturb the underground line. When a tree blows
over, if it's roots are around the line, then it will be ripped out with the
tree. A conduit won't help any.
Posted by hallerb@aol.com on August 2, 2010, 8:01 pm
> Our 14Kv cables are installed in duct banks with concrete around them for
> major runs down streets. backyards get direct burial cables and this could
> be a problem.
> I have news for them. When you have direct burial, or conduit buried cable,
> you still have to keep large growth/deep rooted trees from establishing
> themselves. The roots will disturb the underground line. When a tree blows
> over, if it's roots are around the line, then it will be ripped out with the
> tree. A conduit won't help any.
when you have overhead cables trees fall bringing down lines, winds
damage lines, vehicles talke out poles, and perhaps worst of all many
of these bad days occur in poor weather conditions.......
I have watched from too close by a tree trimmer down a 14K line,
taking out power for miles. the tree he was trimming was mine:( and
after this cut I was going to help direct traffic. I would of been
killed the line fell on the street where I would of been standing.
the arcing line left a carbon trail on the street tll it was repaved 5
or 6 years later.
from just a safety persperctive underground lines are safer
XML site map
> without fighting the power company, but in a round about way, they are
> going to have to have those trees removed to replace the underground lines
> in 20 years. So there is no way to win.