Isolation Transformer test
Isolation Transformer test
(OP)
Hi friends!
I am a mechanical engineer, but I need to know the isolation between primary and secondary and secondary to ground for a 150 KV type isolation transformer. Can anybody suggest where I can find the procerure for this. Is there any ISO guideline for this?
Thanks
Arun
I am a mechanical engineer, but I need to know the isolation between primary and secondary and secondary to ground for a 150 KV type isolation transformer. Can anybody suggest where I can find the procerure for this. Is there any ISO guideline for this?
Thanks
Arun
"Knowledge is power"






RE: Isolation Transformer test
1-on hign voltage (with lo side grounded)
2-on low side (with high side grounded)
3-on low and high side(at the same time)be carreful to have an clean and a bit of isolated jumper
normally number 3 gives you the lowest of 1 and 2
if you have doubt on the insulation you can rise the test kv to work the insulation.
since this seem to be a big transformer, maybe a pf (doble testing) would be to consider
doble gives you much more info on the state of the insulation
RE: Isolation Transformer test
Thanks for your advice. I have already done maintainance test with 1000 v megger. I heard about lightning impulse test. Can that be used for Isolation transformer. I would like to know if ISO or any othe code gives guideline for it?
Arun
"Knowledge is power"
RE: Isolation Transformer test
RE: Isolation Transformer test
I am testing insulation resistance with a 1000 V megger. This resistance tells us something about the health of insulation. If there is a degradation of insulation this resistance goes down and more leakage occurs through the insulation which ultimately results in loss of voltage.
Now the problem is that, although you may get a good insulation resistance at this 1000 v but when you apply actual voltage , still leakage may be more than the estimated one due to dynamic behaviour of solid and liquid insulators.
Any suggestions?
Arun
"Knowledge is power"
RE: Isolation Transformer test
And of course you are perfectly right, that energizing with real voltage is something very different from insulation resistance test, never mind 1000 or 5000 V.
RE: Isolation Transformer test
adequate. As for the lightning impulse test, you must
be refering to the BIL (Basic Impulse Lightning). This is not a routine test as it may be destructive. It it used for newly designed equipment.
RE: Isolation Transformer test
What is the kVA? Is it 3phase or single phase?
That will determine the types of tests. If it is less than 600 volts then the megger tests at 1000 vdc would be generally acceptable for operation. If its really 150kV a doble test, turns ratio, among other tests would be expected.
RE: Isolation Transformer test
It is a 100 KV, single phase isolation transformer with 20 amp. rating. This is not a step up or step down transformer. It is a 1:1 transformer. The isolation between primary to seconday is 100 kv and secondary to ground also 100 kv.
Thanks
Arun
"Knowledge is power"
RE: Isolation Transformer test
If your transformer is more along the size of a TV, then it's a 150 kVA unit (or 100? - you changed your story), not 150 kV.
Best Regards,