Power Transformer Short Circuit Type Test
Power Transformer Short Circuit Type Test
(OP)
One of the major requirement of our utility company is to require prospective power transformer suppliers to submit a type test report performed by an independent testing company like KEMA or CESI. The particular test that we are interested is the full short circuit test done either at KEMA or CESI test facilities or witnessed by KEMA or CESI representatives in case the test was done at the suppliers factory.
Recently, we have one supplier who submitted a short circuit type test report for a 1-phase transformer instead of the required 3-phase test. Is it acceptable to accept this 1-phase test in lieu of the required 3-phase test?
Appreciate any comments on this inquiry.
Recently, we have one supplier who submitted a short circuit type test report for a 1-phase transformer instead of the required 3-phase test. Is it acceptable to accept this 1-phase test in lieu of the required 3-phase test?
Appreciate any comments on this inquiry.






RE: Power Transformer Short Circuit Type Test
RE: Power Transformer Short Circuit Type Test
MY inquiry is about the bidder submitting a short circuit type test report done on a 500mva, 345kv 1-phase transformer unit which they have claimed to be acceptable to our required 3-phase short circuit test for a 230kv, 300mva, auto-transformer unit. We know that it is not possible to construct a 3-phase unit on a 1500 MVA bank rating but we only require 3-phase short circuit test on a smaller 300mva, 230kv-115kv auto-pxf which we have many units installed in our substations.
The question is; can we accept the 1-phase short circuit test result from a big transformer unit instead of our required 3-phase test for a smaller transformer unit.
Again to prc, thanks for the response. Can you provide a reference technical document on this specific issue?
RE: Power Transformer Short Circuit Type Test
How much money will be saved by doing a single phase test rather than a three phase test?
Bill
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"Why not the best?"
Jimmy Carter
RE: Power Transformer Short Circuit Type Test
waross- Short circuit test in high power labs (with special generators) is done like this. If the rating is say up 100 MVA 10 % impedance 3 phase ( for 1000 MVA short circuit power, the lab generator capacity should be 6000 MVA or more to take care of the drop etc) 3 Phase test can be done up to 500-1000 MVA . But if the SC rating is more, lab will go for 1.5 phase test ie single phase voltage will be used and full power in one phase and half power in other two phases. But if the Sc power exceeds even that single phase test will be done on one phase and repeat in other phases. Cost of testing -well I will say not much difference. It is more based on size of transformer and number of shifts involved.
RE: Power Transformer Short Circuit Type Test
To answer prc inquiry, the 1-phase unit rated 500mva, 345kv is an auto transformer type.
To waross, I cannot provide a cost comparison because our office is not privy to the bid cost.
Many thanks again to both of you.
RE: Power Transformer Short Circuit Type Test
The cost of testing I was considering was the cost to the supplier of an in-house test versus the cost of sending the transformer out to a lab with greater capacity testing gear to provide test results that meet the bid specs.
Bill
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"Why not the best?"
Jimmy Carter
RE: Power Transformer Short Circuit Type Test
RE: Power Transformer Short Circuit Type Test
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