Transformer vault filled with water.

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electrofelon

electrofelon

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Cherry Valley NY, Seattle, WA
I am not sure if this is a dumb question or not. Is it typical for a underground transformer vault to fill with water? Is this bad? Are the transformers and connections designed for this? I've got a utility vault with three 25.5 kv to 120/208 pole type units that have probably been underwater for 40 years.
 
If it's still going after 40 years, I'd say it's just fine.:D

But, I have not seen this before. All the vaults I see, have padmounts sitting on them.
 
Low Voltage Network Protectors which are typically found in vaults are submersible.

We would pressurize the tank with air, dip it into a tank of water, & watch for bubbles as the last factory test.
 
Underground Xfmr Vaults

Underground Xfmr Vaults

My experience with this happened a few yrs ago when a sidewalk underground vault flooded due to a water main break in downtown SF. The padmount was submersible but the cable connections to the bus duct that fed a Telco central office were not. Bam! building went to emer gen. The gen vendor hooked up cables to the bus duct from his portable gen on the street while water was still draining out of it and his breaker on the portable tripped. :angel: That's when we were called in to "Megger the bus duct to the CO." I looked at the POCO foreman and asked " you want me to megger a bus duct with water coming out of it?" :jawdrop::eek:
There was a sump pump in the vault that was never wired in :D
The CO ran on gen till the EC ran temp cables from the padmount to the main switchboard (3000A, 480V.) Get this, the vault flooded a second time a few month later for the same reason after the temp cables were installed and with the same results :slaphead::roll:
The bus duct was finally replaced a year later :rotflmao:with everything back to normal, but everyone has their fingers crossed! ;)
 
I’ve had a switchroom flooded with coal slurry to about 2½Ft. The main 433V switchboard was still live but the steam from the busbars made the room like a sauna.

Pity about the 433/110V transformer, that didn’t survive.
 
In a related story...

A friend of mine was working in a large government building in downtown Houston when Hurricane Ike hit. The downtown grid network went down and the streets were flooded. The building had a full site backup generator, so that was good. The generator, however, was in the basement, which wasn't good.
 
We have designed/manufactured water cooled transformer/rectifier systems. But the water was on the inside.....
 
kwired said:
You beat me to it, I was going to mention something about water cooled units:)
Click to expand...
For us these were usually high current (10kA) low voltage rectifiers. We have used liquid cooling on units up to 3.3kV but that was silicone oil - Dow Corning 561 as I recall.

Sorry for the digression, mods.
 
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