Overhead Power Lines Dangerous To Life and Property

[kwired]

Flooding and some wind in NYC, but notice how the lights are still on:

But any underground transformer vaults or other enclosures especially for MV equipment potentially can be higher shock hazard during such flooding. Hopefully they are sealed to keep water from entering them?

 

[Hv&Lv]

But any underground transformer vaults or other enclosures especially for MV equipment potentially can be higher shock hazard during such flooding. Hopefully they are sealed to keep water from entering them?

I have witnessed pad mount transformers floating in flood events. still energized.
the elbows are required to maintain their seal to stop water intrusion.
I believe the standard is 6’ deep.
Whoever terminates the elbows has the responsibility to seal the jacket for the CN.
cold shrinks, or aqua seal with tape is most popular.

 

[mbrooke]

I have witnessed pad mount transformers floating in flood events. still energized.
the elbows are required to maintain their seal to stop water intrusion.
I believe the standard is 6’ deep.
Whoever terminates the elbows has the responsibility to seal the jacket for the CN.
cold shrinks, or aqua seal with tape is most popular.

Don't those elbows flash over internally when they are pulled out on equipment higher than 15kv?

 

[mbrooke]

But any underground transformer vaults or other enclosures especially for MV equipment potentially can be higher shock hazard during such flooding. Hopefully they are sealed to keep water from entering them?

Here is an interesting view point in regards to undergrounding:

https://nypost.com/2012/10/19/cell-charges-socket-to-the-city/

This homeless guy has found the ultimate power hack

This vagrant doesn’t let being homeless get in the way of gluing himself to the TV or getting a close shave with an electric razor. But unlike other New Yorkers, Guy Ritchie does it all on the stre…

nypost.com

 

[paulengr]

But any underground transformer vaults or other enclosures especially for MV equipment potentially can be higher shock hazard during such flooding. Hopefully they are sealed to keep water from entering them?

Baloney. Would you enter a submerged vault without testing first? Scratch that…ANY vault? Most of the equipment for the City of Charleston, SC for instance is underwater indefinitely. Ok another hint: why do pole lines not self destruct or become major shock hazards when it rains? Because water itself isn’t terribly conductive. It’s a myth, it’s only when it mixes with electrolytes that it’s dangerous.

Plus MV equipment is built to very different standards. If I open a LV starter, transformer, etc., both controls and power circuits are right there in my face mixed together. In the vast majority of MV equipment power and controls are in physically separate areas with internal walls. HV and LV sections of transformers are in different compartments. You won’t find yourself gloving up to test control circuits. Plus many MV systems use high resistance grounding where the touch potential current is below 100 mA…fibrillation is impossible. Plus given a 1000 kVA system at say 480 vs 4160, which has the greater arc flash hazard? The 480 system. Simply put there is neither statistical nor theoretical evidence that MV systems are less safe. It’s a total myth.

 

[Hv&Lv]

Don't those elbows flash over internally when they are pulled out on equipment higher than 15kv?

No. We pull 25kV loadbreak elbows at least once a month somewhere on the system.

 

[mbrooke]

No. We pull 25kV loadbreak elbows at least once a month somewhere on the system.

Guess you've got the good kind. I like

With 3 phase tripping (no ferro) on an underground network 22 and 33kv is a going to get common.

 

[mbrooke]

Baloney. Would you enter a submerged vault without testing first? Scratch that…ANY vault? Most of the equipment for the City of Charleston, SC for instance is underwater indefinitely. Ok another hint: why do pole lines not self destruct or become major shock hazards when it rains? Because water itself isn’t terribly conductive. It’s a myth, it’s only when it mixes with electrolytes that it’s dangerous.

And with both hands wrapped around a metal tool. It was metal drills with missing equipment grounds that set the myth, and GFCIs, in motion.

Plus MV equipment is built to very different standards. If I open a LV starter, transformer, etc., both controls and power circuits are right there in my face mixed together. In the vast majority of MV equipment power and controls are in physically separate areas with internal walls. HV and LV sections of transformers are in different compartments. You won’t find yourself gloving up to test control circuits. Plus many MV systems use high resistance grounding where the touch potential current is below 100 mA…fibrillation is impossible. Plus given a 1000 kVA system at say 480 vs 4160, which has the greater arc flash hazard? The 480 system. Simply put there is neither statistical nor theoretical evidence that MV systems are less safe. It’s a total myth.

You, I like you

 

[kwired]

Baloney. Would you enter a submerged vault without testing first? Scratch that…ANY vault? Most of the equipment for the City of Charleston, SC for instance is underwater indefinitely. Ok another hint: why do pole lines not self destruct or become major shock hazards when it rains? Because water itself isn’t terribly conductive. It’s a myth, it’s only when it mixes with electrolytes that it’s dangerous.

Plus MV equipment is built to very different standards. If I open a LV starter, transformer, etc., both controls and power circuits are right there in my face mixed together. In the vast majority of MV equipment power and controls are in physically separate areas with internal walls. HV and LV sections of transformers are in different compartments. You won’t find yourself gloving up to test control circuits. Plus many MV systems use high resistance grounding where the touch potential current is below 100 mA…fibrillation is impossible. Plus given a 1000 kVA system at say 480 vs 4160, which has the greater arc flash hazard? The 480 system. Simply put there is neither statistical nor theoretical evidence that MV systems are less safe. It’s a total myth.

General public isn't entering transformer vaults. I don't know what it all in the NYC subway tunnels, but imagine a pretty good combination of communications, low voltages, medium voltages, etc. How insulated are they should the tunnels flood? IDK, and part of why I bring it up.

Not to mention there still probably going to be some 120 volt items well within touch zones of everyday users that may not be designed for submersion, but then I never been there so I really don't know.

 

[gadfly56]

Flooding and some wind in NYC, but notice how the lights are still on:

Wow!! I had no idea it had been that bad in NYC.

 

[mikeames]

Ok another hint: why do pole lines not self destruct or become major shock hazards when it rains? Because water itself isn’t terribly conductive. It’s a myth, it’s only when it mixes with electrolytes that it’s dangerous.

I never expected such a simple statement from you Paul. While I am not arguing with the facts, its too myopic. Of course distilled water is pretty much an insulator but the random environment introduces enough impurities to make the presence of water dangerous. Take the insulators off those wood poles and they would self destruct when it rains. Flood waters have everything in them. That water is a better conductor cant imagine trying to get a system up in an area like New Orleans when its underwater for months.

I am sure it can be made possible by waterproofing and sealing everything and PLANING for the flood, but if we can do that then why not do the same for the already existing infrastructure?

The ridiculous image of powerlines fallen is a simple fix? Make the standards better. Why reinvent the wheel for a multiple of the cost for a fraction of reliability improvement?

 

[kwired]

I never expected such a simple statement from you Paul. While I am not arguing with the facts, its too myopic. Of course distilled water is pretty much an insulator but the random environment introduces enough impurities to make the presence of water dangerous. Take the insulators off those wood poles and they would self destruct when it rains. Flood waters have everything in them. That water is a better conductor cant imagine trying to get a system up in an area like New Orleans when its underwater for months.

I am sure it can be made possible by waterproofing and sealing everything and PLANING for the flood, but if we can do that then why not do the same for the already existing infrastructure?

The ridiculous image of powerlines fallen is a simple fix? Make the standards better. Why reinvent the wheel for a multiple of the cost for a fraction of reliability improvement?

Agree. Pure water is an insulator, but it doesn't stay pure for long out in the wild and absorbs/dissolves impurities that make it more conductive pretty easily.

Under 600 volts can contact that wood pole for much longer than the higher distribution voltages can without destroying it also.

 

[mikeames]

If the idea is to disregard cost and do whatever it takes for 99.99% uptime for everybody then the whole system needs to be changed. Thats silly in my opinion. If your going to start with a clean slate then don't kling to the traditional transmission and distribution. The level of thinking, cost feasibility to put the whole grid underground demands the discussion of different fundamental direction. I am not really for that but its would be silly to invest all the assets in an underground idea without considering how those same assets could potentially make an even more reliable system.

Somebody ask the question but nobody answered. What is the intended goal as a number? is it 99.9% uptimes for ALL residential? What is it? Lets define the problem first, not post one off pics of events and associate it with the entire system.

 

[gadfly56]

If the idea is to disregard cost and do whatever it takes for 99.99% uptime for everybody then the whole system needs to be changed. Thats silly in my opinion. If your going to start with a clean slate then don't kling to the traditional transmission and distribution. The level of thinking, cost feasibility to put the whole grid underground demands the discussion of different fundamental direction. I am not really for that but its would be silly to invest all the assets in an underground idea without considering how those same assets could potentially make an even more reliable system.

Somebody ask the question but nobody answered. What is the intended goal as a number? is it 99.9% uptimes for ALL residential? What is it? Lets define the problem first, not post one off pics of events and associate it with the entire system.

As I posted earlier, in my part of the northeast, we're already there without going underground. I can see Florida being a real challenge with the number of thunderstorms they have and the very high water table, but surely other parts of the country present more tractable scenarios. I recall New England has some real issues when a good storm moves through. Maybe HV and MV distribution in the ground would be an economical approach.

 

[mbrooke]

I recall New England has some real issues when a good storm moves through. Maybe HV and MV distribution in the ground would be an economical approach.

The thing is Florida for the most part has it figured out with concrete poles. Which I recall people telling me they would never be practical should a vehicle collide with them.

However, in New England, NY and NJ it is not uncommon for storms to result in 500,000 customers without service for several days.

 

[gadfly56]

The thing is Florida for the most part has it figured out with concrete poles. Which I recall people telling me they would never be practical should a vehicle collide with them.

However, in New England, NY and NJ it is not uncommon for storms to result in 500,000 customers without service for several days.

In NJ it's usually branches knocking down the service drop or the lines in the neighborhood. Except for yesterday when we lost power again for about an hour and a half. Lightning hit the feeder cable from JCP&L to our municipal POCO.

 

[mbrooke]

In NJ it's usually branches knocking down the service drop or the lines in the neighborhood. Except for yesterday when we lost power again for about an hour and a half. Lightning hit the feeder cable from JCP&L to our municipal POCO.

Undergrounding can solve this and more.

Consider yourself lucky, in CT for some the outages lasted a few days.

Had Elsa come a few miles closer the story would have been different.

 

[mikeames]

Undergrounding can solve this and more.

Consider yourself lucky, in CT for some the outages lasted a few days.

Had Elsa come a few miles closer the story would have been different.

Sure it can solve the lightning problem. I am not against solving problems if an obvious solution exists, but it doesn't here. This is a massive scale infrastructure. Its elementary to look at a problem in singularity and apply it to a system the size of the grid. Simply looking at it an saying "burry it" is a simplistic knee jerk solution. That's not to say it's not a solution but why have this conversation until other options have been debated. You suggested doing this change over 50, 60 or 100 year period. What if there is a nano-tech break through in 50 years with battery tech and it makes the grid less critical? Think about the assumption there. Imagine if the telephone company said the same in 1900. That's static thinking and problems of this scale require critical dynamic thinking. After all the Flint Michigan water utilities are all underground yet have many many issues as do many utilities in city areas. So why don't the cities just re-do those systems? Its not so easy underground. So underground is not a permanent solution without issues.

So without debating a less centralized distributions system, future high efficiency alternatives sources that don't exist yet or other solutions lets focus on what the problem is you would like to fix. Its reliability, but on what scale? Rural? Natural disaster events, all of the above? What does a successful system look like if the current system is below standard? Pointing to localized outages is hardly reflective on the whole system.

Why not simply address the simple issues that create the events you see as problems. So if power lines are blown over increase that standards? Concrete poles seem like a fantastic idea in my opinion. As others have said, putting developments or neighborhoods underground seems reasonable and does seem to be the norm in urban developments today. Trees falling on lines, cut the trees back, raise the lines, or both?

I have zero experience with utilities or the standards imposed on them. Perhaps they have been left to make too many decisions on their own putting the cost/reliability factor on the ragged edge. Perhaps adjusting that a bit so the cost of the service increase a little but the reliability increases by a multiple is worth it. Putting the whole system underground does not make sense. Electricity is our most reliable utility. Its pretty transparent to most of society. That's testimony to its reliability. It can be improved, but I don't feel it needs a complete overhaul. If it does then all options need to be tabled.

 

[petersonra]

I have zero experience with utilities or the standards imposed on them. Perhaps they have been left to make too many decisions on their own putting the cost/reliability factor on the ragged edge. Perhaps adjusting that a bit so the cost of the service increase a little but the reliability increases by a multiple is worth it. Putting the whole system underground does not make sense. Electricity is our most reliable utility. Its pretty transparent to most of society. That's testimony to its reliability. It can be improved, but I don't feel it needs a complete overhaul. If it does then all options need to be tabled.

Most places the utility has little say in how much money they are allowed to spend on infrastructure. It is all determined by politicians who want it to be as cheap as possible so the voters don't vote them out of office.

Improving the standards for new developments is not as painful to the voters because they do not see it as a tax increase and blame the politicians. I think virtually all utilities in urban areas are going to go underground in new construction. But it is hard to see where the money would come from to move existing above ground utilities UG without there being a voter revolt and subsequent shortage of tar and feathers.

 

[mikeames]

View attachment 2557114

So , on the contrary.....

Lets mandate to the individual what the government does with taxpayer money. Lets require the neighborhoods to have 16 feeders that are impervious to rain, ICE, Lightning, Trees, Accidents, squirrels, earthquakes and more.... Lets boast how amazing the reliability is, nobody will ever loose power. That's our goal!

What will that utility hook up fee be for a new residence? People want to build a new house, the electric hook up fee will be $75K but hey, it amazingly reliable. Your welcome. Another silly meme done by a HS student who cant evaluate the whole picture.