Overhead Power Lines Dangerous To Life and Property

Status
Not open for further replies.

mbrooke

Batteries Included
Location
United States
Occupation
Technician
And don't think I don't know what your doing. You know the mods will delete this thread and that is your goal.

All because the thought of pulling power lines under ground goes against the "norm"

I put norm in quotes because plenty of other countries found a way to get distro underground.
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Ok, back to the underground, UG lines do not last forever, it is much more costly and time consuming to repair a failed underground line than an overhead. Georgia Power has a lot of secondaries failing in residential communities. If the customer is lucky enough, only one conductor fails, and the poco will put a temporary transformer on a cart next to the meter to derive 120/240 to serve the house. Usually takes a week or two before than can come out and do an underground bore to replace the defective cable.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Ok, back to the underground, UG lines do not last forever, it is much more costly and time consuming to repair a failed underground line than an overhead. Georgia Power has a lot of secondaries failing in residential communities. If the customer is lucky enough, only one conductor fails, and the poco will put a temporary transformer on a cart next to the meter to derive 120/240 to serve the house. Usually takes a week or two before than can come out and do an underground bore to replace the defective cable.



I agree, however I think a looped or networked approach may help.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Something like this. 2-5 primary feeder cables with 2-5 transformers with their secondaries in parallel. Loss of any feeder cable results in the secondary network protector opening, while the reaming 1-4 units take on the remaining load. Customers sees no interruption of service.


1625514343906.png
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
yes they do MBrooke....

but you have to consider that
A) they needed to rebuild after '45
B) they're smaller countries

~RJ~


Right, however roughly speaking, the load density per foot in Maryland, NJ, parts of CT and parts of Mass rivals many smaller countries.

Denser areas could work on a network, smaller areas on a ring with "smart switching"
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Actually, the PV guys have a grand argument for their 'idea' of distribution juxtaposed to our inadequate and ailing infrastructure

~RJ~
Problem is, PV failure rate is much higher than even the underground HV lines. IKEA keeps a large stash of replacement panels in their electrical room. Can’t see it paying off for them.
 

kwired

Electron manager
Location
NE Nebraska
Most new sub divisions are underground. Rarely is there an outage due to the underground portion.
There is still likely transmission lines and maybe a certain amount of local distribution lines that are overhead before entering the sub division that is all underground.

One small town municipal POCO near me no longer allows service drops for new installations or even upgrades to existing services. Has to go underground. Their medium voltage distribution is mostly overhead lines though with some the newer sub divisional areas that are all underground.

They mostly came up with this policy after having ice storms that caused a lot of damage two years in a row, 2005 and 2006. They figured the bulk of the repairs was associated with overhead service drop conductors (usually tree branches falling on the line) and somewhat minimal damages to the general distribution
 

kwired

Electron manager
Location
NE Nebraska
Something like this. 2-5 primary feeder cables with 2-5 transformers with their secondaries in parallel. Loss of any feeder cable results in the secondary network protector opening, while the reaming 1-4 units take on the remaining load. Customers sees no interruption of service.


View attachment 2557030
That kind of means without switching to something like 416/240 systems they have in Europe we will have 208/120 available at these homes where some areas have electric heating and such that now is sized on 240 volt input and not 208 input. It was easier to rebuild those European countries after WWII when there was little to nothing left to have to try to make run again and you can select any system design you want.

The rural areas, the MV/LV transformers are going to be placed pretty close to the supplied load, like they already are in most cases.
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
Right, however roughly speaking, the load density per foot in Maryland, NJ, parts of CT and parts of Mass rivals many smaller countries.

Denser areas could work on a network, smaller areas on a ring with "smart switching"
yes, but the prob is the obvious fix may not fit the biz model MBrooke ~RJ~
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
Problem is, PV failure rate is much higher than even the underground HV lines. IKEA keeps a large stash of replacement panels in their electrical room. Can’t see it paying off for them.
well they probably do Hillbilly

i like to dumb things down for objectivity ,......... thus a capitalist system only offers capitalist remedies

i'm sure you follow
:cool:
~RJ~
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
There is still likely transmission lines and maybe a certain amount of local distribution lines that are overhead before entering the sub division that is all underground.

One small town municipal POCO near me no longer allows service drops for new installations or even upgrades to existing services. Has to go underground. Their medium voltage distribution is mostly overhead lines though with some the newer sub divisional areas that are all underground.

They mostly came up with this policy after having ice storms that caused a lot of damage two years in a row, 2005 and 2006. They figured the bulk of the repairs was associated with overhead service drop conductors (usually tree branches falling on the line) and somewhat minimal damages to the general distribution

That is true, most sub divisions are fed by overhead lines.

Thats a good start IMO :)


Storms are what get people to re-think overhead.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
That kind of means without switching to something like 416/240 systems they have in Europe we will have 208/120 available at these homes where some areas have electric heating and such that now is sized on 240 volt input and not 208 input. It was easier to rebuild those European countries after WWII when there was little to nothing left to have to try to make run again and you can select any system design you want.

The rural areas, the MV/LV transformers are going to be placed pretty close to the supplied load, like they already are in most cases.



This is I think a big hold back in undergrounding. At 120/208Y secondary feeders would need to be 4 times the size. Twice to take into account double the current, and twice to get the same voltage drop as with a 416Y system.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Stop trying to de-rail every single thing you guys refuse to admit you were wrong about regarding electricity.

I made it clear, end the politics. It has nothing to do with this discussion.
I don't see how you can take politics out of it since the only way you're going to be able to get people to pay for it is to hold a gun to their head, and that is a political solution to a technical problem.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
I think before we commit to another trillion dollar boondoggle we should decide what level of service we want. Average it over 1000 days. 95% uptime still allows for 50 days over three years with no power. Even 99% is 10 days in three years of no power. My guess is most get 99% already. How much better do you think is needed?
 

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Engineer
Outage duration is also something to consider. An hour and a half outage once a week would be 99% uptime, and not catastrophic -- pipes won't freeze, food won't spoil and people won't die. But an 88-hour outage once a year -- also 99% uptime -- will have much more-serious ramifications.

I don't think anybody's willing to settle for 99% uptime.
 
Status
Not open for further replies.
Top