Oil Filled Transformer
Oil Filled Transformer
(OP)
We have a 1986 vintage Westinghouse 2000KVA 23kV-480V 65 deg C rise transformer showing some interesting characteristics under a thermal inspection (please note there are no oil analysis or service issues):
1. An entire bank of cooling fins appear clogged/disconnected. How is this possible? Additional cooling fins at the same level are fine (the 1.5" tube/manifold for the fins is clogged). I would assume material large enough to clog this would cause much bigger issues.
2. The exterior shell of the transformer shows elevated temps (155 deg F, 40 deg ambient) on the side of the clogged fins (makes sense, right). Should I be concerned?
3. The oil temperature gauge is located on the radiator that is clogged, rendering it useless.
Does anyone know who to contact for Westinghouse transformer support?
Thanks.......
1. An entire bank of cooling fins appear clogged/disconnected. How is this possible? Additional cooling fins at the same level are fine (the 1.5" tube/manifold for the fins is clogged). I would assume material large enough to clog this would cause much bigger issues.
2. The exterior shell of the transformer shows elevated temps (155 deg F, 40 deg ambient) on the side of the clogged fins (makes sense, right). Should I be concerned?
3. The oil temperature gauge is located on the radiator that is clogged, rendering it useless.
Does anyone know who to contact for Westinghouse transformer support?
Thanks.......






RE: Oil Filled Transformer
RE: Oil Filled Transformer
Is that 40 deg F or C ambient? The 155 deg F operating temperature is only 68 deg C which doesn't sound like a problem, but the oil is stagnant and could be sludging up on the non-circulating side.
I would not top the oil with the tranformer energized.
RE: Oil Filled Transformer
Ambient is about 40 degF
That's what has me puzzled, the transformer is setting level, but the 2 other radiators are circulating normal. the liquid level gauge is between the "25deg" and "LO" range. Your right, it does sound like it is low on oil, perhaps a topping off (de-energized) is in order ....
RE: Oil Filled Transformer
RE: Oil Filled Transformer
RE: Oil Filled Transformer
RE: Oil Filled Transformer
RE: Oil Filled Transformer
So ... part of me says the oil is part of "the insulation", the oil temp has be very close to the tank exterior (1/4" steel should not provide much insulation), so we are still within the temp. rise rating of the transformer.
ANOTHER part of me says if you are reading 140degF on the tank exterior, the windings would be much higher.
Knowing that temp gauges read the oil temp, is that what is used to determine "temp rise" rating? (the oil temp).
This is a very difficult question to answer.
RE: Oil Filled Transformer
I am just curious
RE: Oil Filled Transformer
Yes, the temp gauge reads oil temp near the core and should read higher than the (peak) ambient temp. But the gauge + ambient (In the room) should not exceed the max rise rating.
140F is not very hot, your problem seems to be level and possible sludge clogging cooling fins
RE: Oil Filled Transformer
Usually you can use a filtration rig to remove the sludge, but the problem is not the sludge, its what is producing the sludge, thats what needs to be focused on.
RE: Oil Filled Transformer
1.) Repair the cause of the moisture ingestion.
2.) Have the unit de-hydrated (on-line is a possibility)or,
3.) Replace the fluid
Either way you go, you should have a Furanic Compound Analysis performed to determine the amount of insulation degradation before replacing or processing the fluid. Once the repairs are completed, full electrical testing should be performed at the first available opportunity by a qualified electrical testing firm.
RE: Oil Filled Transformer
Top or bottom one.
RE: Oil Filled Transformer
There unit doesn't have radiator valves.
The manufacturere seems to think the level is low as well. At 25degC, the oil should be midway between the top manifold.
RE: Oil Filled Transformer
RE: Oil Filled Transformer