OK Power company guys ....... What is it?

Status
Not open for further replies.
iwire

iwire

Moderator
Staff member
Location
Massachusetts
NHPOCOUnit13.jpg

I saw this near where I am vacationing.

Is it a voltage regulator?
 
Do a patch around the blown up one, while the parts are being sourced to repair it.
 
We've got a lot of them sitting in our area, mostly near newer developments. I figured the POCO miscalculated their AC loads and had to boost things a bit ;) IIRC, they're mostly stepping down from 12kv to the 4kv lines here.
 
A mobile transformer. Looking at set up it looks its an autotransformer. The incoming feed maybe 24kv and out going 13.8Kv. Its about 5-7MVA. This is a common practice
 
That is a mobile substation. Utilities will use this sub when there is a need to take an existing sub out of service. The utility may be taking the old sub out and replacing it with a new one. The length of time it take to do this requires some method to keep the power flowing.
 
Besides the trannie sitting there, can't one tell the approximate power in and out by the isolation fin's at each end, as shown?

I'm not sure of exact name of disc's...

I thought it was 2KV per isolation disc...
 
72.5kv said:
A mobile transformer. Looking at set up it looks its an autotransformer. The incoming feed maybe 24kv and out going 13.8Kv. Its about 5-7MVA. This is a common practice
Click to expand...

That seems about right but it looks more like 20-30 MVA and 35-70 kV. Hard to tell without someone in the picture, where were you Bob?
 
Last edited:
cadpoint said:
Besides the trannie sitting there, can't one tell the approximate power in and out by the isolation fin's at each end, as shown?

I'm not sure of exact name of disc's...

I thought it was 2KV per isolation disc...
Click to expand...

No such rule. well not really. Every area of the country has different kV/disc standards, depending on environmential conditions and the ratio has changed many times over the years in each area depending on vintage of insulators used.

I read a great white paper on the different ratios, very interesting (to me), I will see if I can find it again and post it.
 
most transformers over the 7MVA rating will have the radiators on it and the above that the cooling fans and oil pumps. At best those bushing are 35kV rated.

The largest transformer I have workout around is 1500MVA. Each phase is 500MVA 525kV in 241.5kV out.
 
Last edited:
I had to run out to dinner ......

al hildenbrand said:
Do a patch around the blown up one, while the parts are being sourced to repair it.
Click to expand...

I do not understand.:confused:

chris kennedy said:
Looks like an amusement park ride, your on vacation, hop on.

Have the wife take pictures.
Click to expand...

al hildenbrand said:
Wait for me!!! I want to turn it on for Bob!
Click to expand...

You guys are the best. :grin:

Funny it did remind me of a ride as it had a strong smell of hot oil.

StephenSDH said:
Its an electric only tractor trailer. Crash testing hasn't gone well yet.
Click to expand...

:grin:

72.5kv said:
most transformers over the 7MVA rating will have the radiators on it and the above that the cooling fans and oil pumps. At best those bushing are 35kV rated.
Click to expand...

This appears to me to have pumps, fans and radiators.

Hear is a picture of the other side.

NHPOCOUnit05.jpg


Close up.

NHPOCOUnit10.jpg


The fence was really in the way of good pictures, I will have to go back with bolt cutters.




Here is a map, the unit was at the intersection of White Moutain Road and Village Road.

POCOUnitMap.jpg


There is a set of primaries running North South along White Mountain Road, there was another set connected to them running East along Village Road.

At some point you can see they cut the set heading East free from the North South set and put this unit into that circuit.

There are no other sub stations I have seen but they would be easy to hide in the hills and valleys.
 
Last edited:
iwire said:
This appears to me to have pumps, fans and radiators.
Click to expand...

The additional cooling improves the short term rating of the transformer.

Utility transformers are designed to be overloaded to hell and back and still work for 50 years, and additional cooling allows a bigger or longer overload. Particularly handy when a substation drops out of service and another has to shoulder the additional load for a while.

All of the zone substation transformers installed in the last few decades have addition forced cooling hereabouts.
 
Status
Not open for further replies.
Top