dry type 2500 kVA transformer varnish melting
dry type 2500 kVA transformer varnish melting
(OP)
One of our transformers began to exhibit excessive vibrating and noise. We shut it down, and this is what we found (see photos). Has anyone ever experienced this before and what could be the cause?






RE: dry type 2500 kVA transformer varnish melting
RE: dry type 2500 kVA transformer varnish melting
Can you safely arrange a thermographic survey while it is energised, bearing in mind the hazards you will be exposed to during the survey?
RE: dry type 2500 kVA transformer varnish melting
Are the core bolts all tight?
Is the load excessive (what % of load was it at) or unbalanced? (is it possible that the TX is single phased?)
David
RE: dry type 2500 kVA transformer varnish melting
Problem: transformer exposed to incoming single phase fault situation for 91 minutes before H.V. breaker tripped
RE: dry type 2500 kVA transformer varnish melting
RE: dry type 2500 kVA transformer varnish melting
In some cases, a VFD can initiate and maintain high frequency ringing on the primary side and that leads to an overheated core. One "unhappy" combination is when the primary is fed from a cable grid and supplies an CSI inverter. The steps associated with the CSI switching then initiates ringing in the primary with several kHz and quite high amplitudes. That heats the core a lot.
Has this transformer been running for years with the same load? Or is it a new installation? Has anything been changed lately? More load? Changes on the primary side? Is the transformer from a reputable manufacturer? Or is it one of those Gonella transformers that used to "Darwin eliminate" themselves from the surface of the Earth?
Gunnar Englund
www.gke.org
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Half full - Half empty? I don't mind. It's what in it that counts.
RE: dry type 2500 kVA transformer varnish melting
Bill
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"Why not the best?"
Jimmy Carter
RE: dry type 2500 kVA transformer varnish melting