Corrosion Transformer

[Marvo]

I'd agree from my relatively limited experience of MV Tx's they're damn reliable. You cite lack of maintenance as being the underlying issue but I'd also suggest you check for external environmental factors that may be responsible for accelerating corrosion and obviously check all the earthing points are in tact and connected and within impedance recommendations.

 

[brookster]

As the oil is in a sealed environment, it shouldn't ever need changing, not unless there has been some internal fault or moisture has managed to enter and contaminate the oil. Typically every TX should be inspected regularly and oil samples taken to confirm it's insulation properties are within specification with no particles in suspension. How this TX has got to a point where oil levels are so low, it's not registering on the sight glass, means that it has been neglected for a very long time.

Don't be too bothered about rust spots, the tank and cooling pipes are thicker than you may think. Leaks are more likely to be found at bushings and at points of failed poorly made welds...

What do you mean, by this TX going ''---- up'' ??

Acidity checks must be carried out every 3 years to make sure your oil hasn't become highly acidic which would cause problems over time.(Along with other common tests as part of a decent maint programme/ if this had been done the tranny wouldn't be in this condition today.)
A common thing that happens is that the varnish from the windings can increase this acidity level.
To say a transformer shouldn't ever need its oil changing is pretty ???? I know it doesn't quench an arc but it does cool the transformer and protect against corona.

Second point : It's got a hole in it.

As already stated the hole is in the bottom under the tank, once rust has happened on the level on this transformer welding is only delaying the cost of a replacement. It's actually more cost effective to just get a new one, spots are everywhere (bad spots not cosmetic)

Either way regarding PCBs maintenance or testing for PCBs hasn't been done so it's ill advised to just assume they are not present being an unknown.

This WILL have to be tested for to arrange disposal, if none cheap disposal if some dear disposal!

 

[Knobhead]

Most cement kilns are becoming waste disposal units with a byproduct of clinker nowadays.

Thought I’d drag you in with that one!

Solvents, waste printing ink, PCB’s and old tyres all get slung in the kiln mix.

I hope you all believe RoB and I, the emissions and product are contaminate free.

The temperatures are so high nothing survives, if it survives the calcining stage, it won’t survive the pre calciner/pre heat with its secondary fuel injection. The temperatures are stupid. The steel wire in the tyres stood no chance, vaporised and then taken up by the cement kilns raw feed (its so called meal) to improve the cements setting properties.

The emissions are monitored constantly, any reading out of spec and the kiln would automatically revert to just coal as its fuel. Coal has to be there as the ignition fuel for the other crap.

I tested the sampling equipment with known noxious contaminates every day. (I should be dead!)
It was my signature on the emissions log for years!

 

[Engineer54]

Acidity checks must be carried out every 3 years to make sure your oil hasn't become highly acidic which would cause problems over time.(Along with other common tests as part of a decent maint programme/ if this had been done the tranny wouldn't be in this condition today.)
A common thing that happens is that the varnish from the windings can increase this acidity level.
To say a transformer shouldn't ever need its oil changing is pretty ???? I know it doesn't quench an arc but it does cool the transformer and protect against corona.

Second point : It's got a hole in it.

As already stated the hole is in the bottom under the tank, once rust has happened on the level on this transformer welding is only delaying the cost of a replacement. It's actually more cost effective to just get a new one, spots are everywhere (bad spots not cosmetic)

Either way regarding PCBs maintenance or testing for PCBs hasn't been done so it's ill advised to just assume they are not present being an unknown.

This WILL have to be tested for to arrange disposal, if none cheap disposal if some dear disposal!

Ha-ha, every 3 years?? You been reading this stuff out of a book or manual?? I've never known any TX have it's oil tested every 3 years. The procedure for drawing the oil from the TX can be quite time consuming too, before you can get a sample that is suitable for breakdown testing.

The only time TX oil needs a complete oil change, is if harmful moisture levels has found it's way into the oil and tank etc, or there is or has been internal overheating or fault!! Those are the conditions that would cause any acidity increase from winding varnish too. A typical maintenance based oil test, is to test for the oils KV breakdown value. Any contaminant will reduce the breakdown value, especially suspended carbon particles. Transformer oils these day's are almost all now synthetic, mineral oil is something from the past, that served it's purpose and has now been superseded. Though the probability of mineral oil being used in your TX is pretty much certain...

So what other common tests to the TX are you referring too?? As far as i can see, this transformer has nothing much on it to test!!

 

[brookster]

Ha-ha, every 3 years?? You been reading this stuff out of a book or manual?? I've never known any TX have it's oil tested every 3 years. The procedure for drawing the oil from the TX can be quite time consuming too, before you can get a sample that is suitable for breakdown testing.

The only time TX oil needs a complete oil change, is if harmful moisture levels has found it's way into the oil and tank etc, or there is or has been internal overheating or fault!! Those are the conditions that would cause any acidity increase from winding varnish too. A typical maintenance based oil test, is to test for the oils KV breakdown value. Any contaminant will reduce the breakdown value, especially suspended carbon particles. Transformer oils these day's are almost all now synthetic, mineral oil is something from the past, that served it's purpose and has now been superseded. Though the probability of mineral oil being used in your TX is pretty much certain...

So what other common tests to the TX are you referring too?? As far as i can see, this transformer has nothing much on it to test!!

Yes on HV equipment guidelines are usually followed. Crackle, acidity, breakdown voltage, breathers and corrosion general condition ect.
It's pretty common work with HV maintenance. No one mentioned replacement of oil apart from you....
Oil gets replaced if it fails any of these tests funnily enough.
3 years is also a moderate maint cut off point, we used to do the tests annually.
Drawing oil from a TX time consuming? really?? what half a day to empty and fill it up and 10 mins to draw a sample .

Also as must TX are old they will most certainly be filled with OM16 and not midel!
I would go as far as 80%

 

[Engineer54]

Yes on HV equipment guidelines are usually followed. Crackle, acidity, breakdown voltage, breathers and corrosion general condition ect.
It's pretty common work with HV maintenance. No one mentioned replacement of oil apart from you....
Oil gets replaced if it fails any of these tests funnily enough.
3 years is also a moderate maint cut off point, we used to do the tests annually.
Drawing oil from a TX time consuming? really?? what half a day to empty and fill it up and 10 mins to draw a sample Also as must TX are old they will most certainly be filled with OM16 and not midel!
I would go as far as 80%

I think you'll find Tony mentioned oil filtering, which is basically oil replacement!!

10 minutes to draw a sample?? If that's how long it takes you to get an acceptable sample, then your doing something wrong!! You'll need the flush the sample valve before you even start, that'll be around half a gallon or so of oil gone before you start!! Then you need to clean the sample vessel with sample oil, draw a sample, ...and if bubbles and suspended particles are present, or colour isn't good you need to discard and draw another sample. That could take 2/3/4 samples before an acceptable sample is obtained!! You would ''Never'' i repeat Never, test a sample that's drawn straight off the draw valve. Think you need to check your oil testing procedures again.... The key to any oil sampling is cleanliness. 90% of all oil sample failures, is not adhering to that simple rule!!

If you tested TX oil annually, your TX oil levels would be getting bloody near critical after 10 years. Never heard anything so daft!! Unless the TX has been working hard, near or at it's full KVA rating for long periods, then a full lab oil testing procedure need not be warranted at less than 5 year periods. And to be honest, i know many that have gone for far longer than that.

The other tests you indicated are not tests, but visual inspections, but i'm assuming you are referring to inspection guidelines!!

 

[Knobhead]

One of the quickest tests for oil is a hot wire test. Heat a steel wire to red heat, plunge it in to the oil, if it foams there is moisture present.
Simple but it will let you know if you have a moisture problem.

I did this on a very old Reyrolle OCB, marked it on the report as oil change required at next inspection. Bloody thing tripped on my watch! Clench bum cheeks, slam the handle forward and run!

Ever tried running while clenching your bum?

 

[Engineer54]

One of the quickest tests for oil is a hot wire test. Heat a steel wire to red heat, plunge it in to the oil, if it foams there is moisture present.
Simple but it will let you know if you have a moisture problem.

I did this on a very old Reyrolle OCB, marked it on the report as oil change required at next inspection. Bloody thing tripped on my watch! Clench bum cheeks, slam the handle forward and run!

Ever tried running while clenching your bum?

That'll be version of the crackle test, which these day's has fallen by the wayside, as any of the modern KV oil testing meters will give you that crackle if moisture is present, as it's ramping up, or when holding a KV value and the meter stirs the oil.

 

[brookster]

I think you'll find Tony mentioned oil filtering, which is basically oil replacement!!

10 minutes to draw a sample?? If that's how long it takes you to get an acceptable sample, then your doing something wrong!! You'll need the flush the sample valve before you even start, that'll be around half a gallon or so of oil gone before you start!! Then you need to clean the sample vessel with sample oil, draw a sample, ...and if bubbles and suspended particles are present, or colour isn't good you need to discard and draw another sample. That could take 2/3/4 samples before an acceptable sample is obtained!! You would ''Never'' i repeat Never, test a sample that's drawn straight off the draw valve. Think you need to check your oil testing procedures again.... The key to any oil sampling is cleanliness. 90% of all oil sample failures, is not adhering to that simple rule!!

If you tested TX oil annually, your TX oil levels would be getting bloody near critical after 10 years. Never heard anything so daft!! Unless the TX has been working hard, near or at it's full KVA rating for long periods, then a full lab oil testing procedure need not be warranted at less than 5 year periods. And to be honest, i know many that have gone for far longer than that.

The other tests you indicated are not tests, but visual inspections, but i'm assuming you are referring to inspection guidelines!!

and were did you get my test procedures from , stop making ****e up.

Top the thing up

Yes 10 minutes to draw a sample, bubbles go away on there own and yes never take first draw

Stop trying to catch me out mate you won't. The daftest thing I've heard is that trannys don't need maint!

Any site worth it's salt that looks after it's equipment to a high standard will have a three year maint program on trannys it's pretty much bog standard anywhere I've worked granted it's all MOD sites but most large sites or companies employ such high standards.

Your attitude i.e 'it will be fine' is the reason things go bang in the night.

'or colour isn't good you need to discard and draw another sample' this statement I can confirm as absolute pash, the colour of oil is the same throughout. Also the colour of the oil means absolutely nothing in regards to passing or failing ANY test. LOL

Just stick to drilling live bus bars

 

[Knobhead]

Tranny’s are high maintenance. The make up costs a bloody fortune!

You’re company can set whatever testing period it likes. It doesn’t make it a national standard, it’s you’re company standard!
I’ve worked on 100’s of power transformers. Only ever changed the oil in three of them. all of the three had tap changer problems so tripped on Buchholz gas.

 

[Engineer54]

and were did you get my test procedures from , stop making ****e up.

Top the thing up

Yes 10 minutes to draw a sample, bubbles go away on there own and yes never take first draw ha, ha, ha!! I suppose the fact that their shouldn't be any bubbles is quite irrelevent to you then??


Stop trying to catch me out mate you won't. The daftest thing I've heard is that trannys don't need maint! I'm not trying to catch you out at all, your doing a pretty good job of that yourself!! I didn't say that, i saying, that most trasnsformers don't get much in the way of actual maintenance, most are lucky to get a regular visual inspection... And for better or for worse, that's the truth of the matter!!

Any site worth it's salt that looks after it's equipment to a high standard will have a three year maint program on trannys it's pretty much bog standard anywhere I've worked granted it's all MOD sites but most large sites or companies employ such high standards. MOD eh, that makes some sense then, they aren't spending their own money!!

Your attitude i.e 'it will be fine' is the reason things go bang in the night. Never had a TX go bang yet, and i wouldn't mind betting, i've fully tested more MV/LV systems (including the TX's) than you've come close too, over the years!!

'or colour isn't good you need to discard and draw another sample' this statement I can confirm as absolute pash, the colour of oil is the same throughout. Also the colour of the oil means absolutely nothing in regards to passing or failing ANY test. LOL ....Again you seem not to have a clue as to what oil colour changes can and do indicate as to what's going on in the Transformer!!

Just stick to drilling live bus bars
I suggest you leave TX maintenance to those that actually know what they are doing, and what they should be looking for!! ....It's certainly not your forte!!

You have proved to me you know very little, probably only what you've been told by others, and you haven't quite got that right either!! Oh, and unlike you i don't have to make anything up, least of all the crap your trying spurt out.

The colour of the oil at the very bottom of the tank (where the draw valve is located) can be quite different to that oil which is circulating. It's where all the crap falls too!! It's you, that's coming out with all the ''pash'' mate!!

 

[Knobhead]

That'll be version of the crackle test, which these day's has fallen by the wayside, as any of the modern KV oil testing meters will give you that crackle if moisture is present, as it's ramping up, or when holding a KV value and the meter stirs the oil.

It’s rough and ready I know. But a quick test it will show moisture. When doing a PILC cable I’d dip a sample of the papers in the hot compound, again if it foamed we had a problem.

I went to GEC to see some OCB’s they were doing up for me.
They then came and did the oil tests on site after I refused to accept them back. The oil had carbon deposits. The carbon had dislodged from the top of the tank in transport. The oil passed but they agreed it didn’t look good so changed it as a good will gesture.
Interesting to see the test rig in action.

 

[brookster]

You have proved to me you know very little, probably only what you've been told by others, and you haven't quite got that right either!! Oh, and unlike you i don't have to make anything up, least of all the crap your trying spurt out.

Wrong on so many level smart arse!

The colour of the oil at the very bottom of the tank (where the draw valve is located) can be quite different to that oil which is circulating. It's where all the crap falls too!! It's you, that's coming out with all the ''pash'' mate!!

No its not - it really isnt - crap falling to the bottom - do you want a darwin award it's called gravity.

and were did you get my test procedures from , stop making ****e up.

Top the thing up

Yes 10 minutes to draw a sample, bubbles go away on there own and yes never take first draw ha, ha, ha!! I suppose the fact that their shouldn't be any bubbles is quite irrelevent to you then??

You do know that the bubbles are made as you draw the bloody oil out the valve!!!

Stop trying to catch me out mate you won't. The daftest thing I've heard is that trannys don't need maint! I'm not trying to catch you out at all, your doing a pretty good job of that yourself!! I didn't say that, i saying, that most trasnsformers don't get much in the way of actual maintenance, most are lucky to get a regular visual inspection... And for better or for worse, that's the truth of the matter!!

Thats absolute crap LOL

Any site worth it's salt that looks after it's equipment to a high standard will have a three year maint program on trannys it's pretty much bog standard anywhere I've worked granted it's all MOD sites but most large sites or companies employ such high standards. MOD eh, that makes some sense then, they aren't spending their own money!!

And you would know that how exactly?

Your attitude i.e 'it will be fine' is the reason things go bang in the night. Never had a TX go bang yet, and i wouldn't mind betting, i've fully tested more MV/LV systems (including the TX's) than you've come close too, over the years!!

I can guarantee you've not, considering you look at them every ten years or so if at all. Some poor so has probably been left with your crap of an install to fix after some douche forgot it need looked at every so often.

'or colour isn't good you need to discard and draw another sample' this statement I can confirm as absolute pash, the colour of oil is the same throughout. Also the colour of the oil means absolutely nothing in regards to passing or failing ANY test. LOL ....Again you seem not to have a clue as to what oil colour changes can and do indicate as to what's going on in the Transformer!!

I've seen more oil than the rigs in Saudi Arabia - it means fck all otherwise it would be pretty important in TX maint - I hate to break this to ya - it's not - PERIOD.
It can give an INDICATION which other tests will shed some light on!!!
Finding other things (IE carbon or Iron deposits) is not the colour either so stop backtracking/twisting , keep digging.)
You find me a guy who can tell me whats wrong with a TX by the colour of the oil and i will find you a liar.

Just stick to drilling live bus bars
I suggest you leave TX maintenance to those that actually know what they are doing, and what they should be looking for!! ....It's certainly not your forte!!

And that my son I can guarantee is not you

You said some of the things you have said on this forum working for any reputable HV company your arse wouldn't even hit the door.

Guru tell me how I would go about finding where the hotspots on my core would be or what I would use to find them and how I would use it?

And why would this be a problem and how could I go about changing this problem

No google now

I'll say it again - I don't take advice from people who drill live bus bars not really good practice or is that how it's done also? Must have missed that one too

Keep your limited knowledge and bad practice in China, k thanx.

 

[Marvo]

Thanks everyone, I think we're done here.

Closed