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Hello, We are quite familiar with the transformer factory acceptance tests, but know very little about high voltage circuit breaker's. Anyone can provide such information? If you have the source document, that will be really good.

Thanks

One of our 1966 ASEA, 75MVA transformer has a damaged conservator bladder. If you have the experience about the transformer conservator bladder replacement, could you share with me what is the ballpark cost of such replacement? Thanks

IS based on nameplate rating, or based on the IEEE 57.91?

DO you disconnect at the end of Hot Spot Winding temmperature gauge, or at the relay end? Is the transformer outage required? Thanks

In my company, all Bank # = Transformer # = Unit #, except one pair (which have same Bank # but different Transformer #).

One of our transformer has the leaks from main tank to the DETC compartment, likely the Barrier board between LTC & main tank failed due to faulty gasket. What's the consequence if we leave it un-fixed soon? Thanks

C1 (%PF): H1, H2, H3 => 1.49, 1.13, 0.74. Hotcollar: H1, H2, H3 => 0.024, 0.03, 0.034. Which test result you would use to judge the integrity of the bushings? THanks

The trend of CO and CO2 is attached. Thanks

I.e. replace the soft strap winding and 1950's standard GE type of clamping system.

THe tertiary is not connected to the load, but its winding temperature gauge reading is highest among the three windings. I would like to listen to your opinion.

We have a 75MVA shell form power transformer. The infrared shows the unusual heat pattern at the low part of tank. Likely it's caused by the stray flux heating. I am interested to know how other utilities' experience dealing with the stray flux heating. 1) will the tray flux heating limit...

We loaded the 75MVA transformer up to .92PU and performed infrared scanning and meantime observed changes of top oil and winding hottest spot temperature gauge. 4 hours after the uploading, the top oil and winding hottest spot readings are 51C and 71C respectively. It's consistent with the...

2010-2012 is the period of solare storm that results in Geo-magnetically Induced Currents (GIC). It occurs in a cycle of 11-12 years. I am interested to know what other companies are doing to pretect their transformers from GIC. Thanks

As it's said, the degree of the short circuit damage depends on the impendance. If the fault location is close to the current source (substation), then the damage will be more severe. My question is, if the cable is 100% loaded and has a fault, compare to the cable that is 20% loaded under...

We have a 3-winding transformer with the negative value of secondary winding impedance. What's the physical meaning of the "Negative Impedance"? Thanks

What's the maximum allowable conductor temperature your company uses for the outdoor substation copper bus bar? 90 degree C? 80 degree C? or 70 degree C? If you use the conductor temperature lower than 90 degree, why? what're the main concerns? THanks

In the new standard, there are two types of 2" copper substation tubular buses - 2" copper, schedule 40, 98%ICAS; and 2" copper, Schedule 80, 98% ICAS. Which one is equivalent to 2" IPS Copper in the old standard? Thanks

Do you have the substation power transformer replacement program? Criteria? Is there any publication of literature about this subject? Thanks

Hi, I am trying to do some researches for ETM. Does anyone know the good reference and literature about ETM for power transformer?