Can electricity conduct through a fine spray of water?

[John S]

I think they just turn power off for that circuit. They have redundant paths to keep power to customers.

[John S]

Really? 200umho is 5000 ohms. So, at 400kV, the dirt (or whatever) would dissipate 32,000,000 (32E6) 32 million Watts. I kinda don't think something is not quite right.

[John S]

Do they have those kinds of systems for 400kV?

[John S]

They produce a megavolt?

[hubops]

Live line power washing has been around for many decades. Corn blasting too ... yep - corn .. John T.

[Rod Speed]

No they don't with 350KV and 500KV transmission lines.

That isnt true either with 350KV and 500KV transmission lines. and we know that because there have been some catastrophes when a mega ice storm or massive gale has brought an entire transmission line down. collapsed some of the towers.

[hubops]

The 230 kV insulators are about 5 feet long - - that's a real big crow ! - - if the secondary was 14 kV those insulators might be ~ 1 foot - an easy short for several critters. John T.

[hubops]

25 Hz hums different than 60 Hz. .. seriously. John T.

[micky]

I watched a composite video today of lots of interesting things, and one was a couple fire engines pumping water on a fairly big fire.

Between one of the fire engines and the fire were 4 or 5 wires between "telephone" poles. Each wire was almost a foot for any other. Eventually there was enormous sparking, a bright white spot equivalent to 3 feet wide that lasted for few seconds followed by flames from the wires for 3 or 4 more seconds and then the video stopped.

The narrator said 10,000 people lost power but he may have just made that up.

But still, the fire department should use deionized water. Maybe that wodld help.

[Rod Speed]

Just not feasible, particularly with a major fire where they need to use water from the hydrants.

[Jasen Betts]

If that electricity supply is properly maintained, A few seconds later the recloser would kick in and reconnect the power.

Probably not ecconomical re-plumbing all the streets to add pipes for DI water or adding fast-enough processing plants to the fire appliances...

I think this is a risk that's worth taking. perhaps some extra training would be more effective.

[hubops]

Once, it was all 25 Hz. The lights would flicker - they still flicker at 60 Hz but we don't notice. I worked in a 25 Hz. generating station mid-late '70's .. not sure when it finally went completely obsolete. John T.

[Colin Bignell]

There is a hint in the title to the video, where it is described as live line washing.

[Colin Bignell]

According to this site, water mist is suitable for sub-station fires because the mist does not conduct electricity:

[hubops]

Niagara had 2 different 25 Hz generating stations and a freq. changer at one of them ; and 25 Hz transmission to a few old heavy industries - 1 in Hamilton. A 25 Hz. line ran to London to a freq. changer there. Also there was some 25 Hz. generation up in northern Ontario supplying mine / smelter loads. The station service at the old Ontario Power GS was still 25 Hz hence the flickering lights. The power system conversion from 25 to 60 Hz was done in Ontario < and USA presumably > in the 1950's.

Some info here, including some photos of the OPGS where I worked for a while in the mid '70s - just a long stones-throw from the foot of the Canadian Niagara Falls :

John T.

[hubops]

I never had the chance to operate one, but I did study the training materials - long forgotten now. ... " slipping poles " comes-to-mind. John T.

[danny burstein]

[lots snipped]

late 1970's NYC had one of those multi week sub zero (F) cold spells. I recall the incandescent lamps in the subway station next door to (what was left of) the Pennsylvania Rail Road station flickering.

I investigated, and it turned out they had been wired into the 25 CPS [a] system used by the rail road for its motive power.

(The subway itself used/uses 650VDC)

Sidenote: they actually blinked (generally not visibly) at _50_ CPS (and now 120, of course) because the power goes through them on both parts of the cycle.

[a] to the yung'uns: That's "cycles per second". None of that fancy shmancy "Hertz" stuff

[Scott Lurndal]

I used to watch PG&E crews clean the insulators on 115Kv lines on the hill behind my house every couple of years. With a helicopter hovering near the tower, one of the crew would hose down the insulator with a power washer. The lines were not de-energized.

[hubops]

Another thing that I never had the pleasure to work with ..

John T.

[micky]

I was kidding.