Water Cooled Transformer - ECN Electrical Forums

Thanks to RODALCO for submitting these pics and info:

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These pictures are from Wairau Valley Road substation in Glenfield, North Shore, Auckland.

This substation is fed from 3 x 110 kV lines ( double cct 110 and single cct 110 lines ).

Maintenance was done on the double 110 kV line to replace the aerial earth wire.
The cct 1 and cct 2 lines were shut down for the whole weekend during the earthing upgrade.
Saturday afternoon the temperature shot up in the switchyard which is in a valley to 35°C(95F),no wind,
This happened on Saturday 10 March 2007 around 1400 hrs.
The 33 kV load went up from 1000 to 1200 Amps.
110 kV current was around 340 Amperes.
Temperature meters increase to critical tripping point 85°C
OFAF rating is for 2 hours only with oil pump running and fans on.
Simple solution I suggested, knocked down the temperature around 5°C within the hour by applying 2 garden hose sprays atop the radiators to assist with extra cooling of the oil. ( We did this also in the Auckland CBD meltdown in 2000 ).

We managed to avoid a trip and large area black out on the north shore.
For the rest of the Saturday and Sunday, during daylight hours we left the hoses running.
At night they were turned off and ammeter readings dropped to around 800 Amperes.

I will add more comments when the photo's are posted.

Raymond ( Rodalco )

And now the images:

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trumpy, we have some at one of our hydro plants that uses water to cool the oil through a heat exchanger, belive it uses lake water.it ends up going down a funnel shaped drain so you can see it running.these trannys are right after the generators.these are hydro type units & there monsters.these are vertical type units with the DC exciter on top. then a smaller plant that used to supply an old mill has horizontal units, with the exciter belt driven.these are proably over 100 yrs old.

Who says water and 'lectricity don't mix?

Very clever solution to a potential major shutdown, rodalco. Have you considered installing some spray jets on all the heat exchangers, rigged so that you'd simply have to hook up a hose and turn on the water? If all the exchangers had an even spray going on, you could probably get more than 5 degrees temperature reduction.

In pic #1, how old is that transformer/inductor in the foreground left side?

Circuit man, send in pics if you can, it sounds interesting!!

edited for spelling (Other than "lectricity, I meant to say it that way.

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In pic #1, how old is that transformer/inductor in the foreground left side?

was wondering that too.(btw)

So how does it feel to have saved the entire town from a blackout Rodalco? Not many can say that. Well done.

At a guess there guys I would say it isn't that old.
I also work for a Power Company as does Ray and we have a turn-around time (locally) of 3-5 years before the transformers (of any size) are replaced, drained, stripped down, re-wound and re-commissioned.
Electrical apprentices here at Electricity Ashburton certainly do thier time in the Transformer shop.
Only way to learn I say, look at how the tranny in front of you is being wound.

A small local municipal utility did that with some of their pole transformers a number of years ago. We had a spell of very hot weather and to protect the transformers and keep the service on, they ran hoses from a house up the pole and ran the water on the can. They are also the water utility and they gave a rebate to the homeowner for the water used.
Don

Who is that up on the pole in pic #6
(The one with the arrow and available signs?)

Is he working on the earthing project, or is that a photoshop job?

John

mxslick These nozzles could have been prepared prior to the actual shutdown but the project managers didn't think of that option.

It was a matter of perhaps an extra half hour and power would have been off by O.T. trip. As a temporary solution it worked well, Indeed for a future constraint it is well worth putting a nozzle on each radiator, althopugh the water pressure from the tap wasn't too flash. 80 metres of garden hose, some splitters, nozzles and cable ties, job done.
The fans actually helped quite well in getting the water to the other 4 radiator blocks.

That transformer on the foreground is T2 (110/33 kV) from the Wairau substation and is ± 30 years old and scheduled for maintenance next year.
It has beeen leaking oil like that for at least 5 years.

Luketrician Haven't heard a formal thank you yet, but that is typical in our industry.
The asset owners auditor and supervisor were on site and were impressed how a simple solution was so effective.

Hotline One of the linemen, I don't know who it was. It was not for a photoshop. Just happened to see it from the distance. He had to use the spikes from his ladder up and through the 110 lines.

Trumpy Thanks for putting the photo's on ECN.

Rodalco, thanks for the prompt reply and insight.

The ironic part is, that 30 year-old transformer will probably continue to outlast the more modern one.

I've heard from some of the guys in the local POCO that the new transformers are, in comparison to the older ones, basically junk, with the actual service life rarely more than 15 years.

I wonder what a person would or could posibly be doing up there that high in the air. just crazy if you ask me.

Originally Posted by john p

I wonder what a person would or could posibly be doing up there that high in the air. just crazy if you ask me.

That Line Mechanic is re-instating a damaged Earth wire that runs over the tops of the poles.
It shields the phases from lightning strikes.

Thanks Mike, that is exactly what was being done there.

He was wearing his safety harness anyway which is strapped around the pole.

This is a very busy road and to recheck a termination, it is easier to climb the pole via ladder and climbing hooks, instead of reclosing the road and get a cherry picker up there.

He was certainly not aware of this distance photo being taken.

Regards

Raymond

Cheers Ray,
I also take it the the lines below him were de-energised, which would to a degree explain the lack of a bucket truck.
As a note to our US friends, we don't as a rule use spikes here to climb poles, although I have struck the odd old pole without climbing studs and have had to take out the old climbing spikes, really hard on the legs if you aren't used to it!.
Most of our HV poles here are concrete (cement) these days with built in studs, wood is on the way out because of our high moisture atmosphere, although there are TONS of wooden poles all over NZ.