Miracle- Power Reamained On In Part Of Venice

[Chetlaham]

This video raised my mood giving me hope and inspiration. Despite the aftermath destruction power remained on at 0:14, 0:32, 0:49, 0:54, and 1:14 in this small portion on Venice Florida. There is something about the hinged globe coming undone on a street light while still being lit. I wish all power systems behaved like this during storms. This has been my dream for sometime and I hope to one day see service continuity being the norm rather than an exception.

 

[tomturbomatic]

The Weather Channel ground crew showed that downtown Sarasota development on the air during the storm. It is a newer development with underground electric service.

 

[Chetlaham]

Underground electric is paying off! <3

They make fully submersible underground distribution equipment which can survive the effects of flooding too. Wind + water resistant. I'll take it!

 

[tolivac]

Underground power service-just about all of them originate from a pole drop somewhere.If you have such service walk or drive your area and you can find the pole drop.In areas where I have underground service-I know where the pole drops feeding it are.They are also fused.And your underground service distribution transformer has a primary fuse in side its case.Besides the pole drop fuse the feed can be on a recloser and sectionalizer-if you get 3 trips the sectionalizer openes the line and a lineman needs to check the circuit and reset.

 

[neptunebob]

Rex, if power lines are all underground and the waterproofing has a leak and there is a flood isn't it possible to short out the circuit and electrocute anyone nearby? I would also wonder if it might be harder for a utility to do a "black start" from no electricity at all, as some Florida utilities might have to do.

 

[tolivac]

If there is a short in the circuits the fuses associated with them will blow.Same with if they have circuit breakers adn reclosers,sectionalizers.Those will try 3 times-then lock out.I watched this happen at my place during Floyd.The transformer serving my block had an overload on it-hummed VERY loud-for 3 shots-then was off.When you have this time for the candles,flashlights,lanterns,and your own generator that is isolated from the power co system.

 

[circlew]

Usually when the power goes off at my house, it will, as Rex mentions, try 3 times to reconnect, but about half the time it fails to do so. It doesn't happen as often anymore since they put the lines in a wooded area about 6 miles away on taller poles. The next street over from me is on a different feed, and if it goes off over there about the same time as my street, I know it's a major outage. Both feeds originate at a substation about 10 miles S.W. of here. Fortunately the substation didn't loose its feed during the July 6 tornado, but several of the circuits originating there failed.

 

[sudsmaster]

In this part of California, we don't get hurricanes, or even tornadoes.

 

We can get earthquakes, but those are few and far between, at least the Big Ones. And unlike hurricanes, they are far more difficult to predict. Some might argue, impossible to predict. The best we can do is to reinforce our buildings, bridges, freeway overpasses, etc.

 

Baby quakes don't count.

 

 

[Chetlaham]

Underground fed by Overhead

For rural and for most suburban circuits-yes.

But you can, and do have cases where the main feeder from the substation is underground all the way up to the pad mounted transformer serving the customer. Basically you've got a 750MCM EPR 600 amp back bone feeding into PMH pad mounted switches where the circuit is then fused down to 200 amps. From there 4/0 AL URD loops in and out of pad mounted transformers. Simple, elegant and easy to restore service if a cable burns up.

Here is what I have in mind, see schematic on page 9:

https://www.sandc.com/globalassets/...ive-bulletin-662-30.pdf?dt=638007296938103353

Auto source transfer for the primary feeder:

https://www.sandc.com/globalassets/...ve-bulletin-663a-30.pdf?dt=638007296958261655

 

[Chetlaham]

@neptunebob: The 13800 volt cables have a bare copper screen around them.

https://www.southwire.com/wire-cable/medium-voltage-primary-underground-distribution/c/c-mvdistmain

The idea is that if the primary insulation (#3) fails, it will instantly arc to the neutral conductor. The impedance (combined electrical admittance) of the hot and neutral conductors are selected so that a fault will cause 1000s of amps of current to flow which will blow the upstream fuse or trip a breaker in a matters of a few cycles. (About 1/60th of a second). That is fast!

This immediately removes any potential danger while indicating that the circuit had an insulation breakdown. Further, automatic switching can isolate the faulted cable and restore power via unaffected portions of the system.

I have an entire underground system planned out for the United States- if people could just understand what underground distribution can bring to civilization overhead would disappear in 7-10 days.

Regarding blackstart in Florida I don't think the transmission system to the North of the Hurricane was effected, so they can route power south as transmission lines are brought back into service. Either way, in my world, all generating plants have blackstart system with N-2 redundancy.