Thanks to RODALCO for submitting these pics and info:
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.
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.
#125149 - 03/22/0712:34 AMRe: Water Cooled Transformer
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. )
Stupid should be painful.
#125150 - 03/22/0703:52 AMRe: Water Cooled Transformer
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.
#125152 - 03/22/0707:30 AMRe: Water Cooled Transformer
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
#125153 - 03/22/0702:43 PMRe: Water Cooled Transformer
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.
The product of rotation, excitation and flux produces electricty.
#125155 - 03/23/0705:33 PMRe: Water Cooled Transformer