Copper Loss of a Transformer

cu loss= i sqr r caluculate current , square it and mutiply it with impidance

Quote "cu loss= i sqr r caluculate current , square it and mutiply it with impidance"

Should be I²R. Not impedance

Two winding Trafo Copper Loss=I primary squared X Res Primary + I secondary squared X Res secondary

At different currents and different temperatures the copper loss can be calculated by appropriate substitution of values.

Thanks for the clear answer. GA from me.

Can you also explain "proximity effect" ?

Self inductance - Skin effect

Mutual Inductance (usually between strands) - proximity effect.

The leakage flux of one strand interacts with the current of the other strand(s) and they (currents) get crowded (Fleming's rule/ maxwell's equations)

UD15

thanks for the help mr. winfield, i really appreciate it a lot. Im trying to dig some more information regarding this transformer losses. im currently at designing stage, i want to calculate the short circuit currents for my system but unfortunately, for the transformer, i only have these data. Im using impedance method my short circuit calculation so that i can size my breakers with correct kaic rating.

Ah, that's why you had the %Z parameter. I didn't notice. Perhaps an article by Jim Phillips, Short Circuit Calculations – Transformer and Source Impedance, will be helpful to you. It's at his website, brainfiller, in the newsletter Archive, http://www.brainfiller.com/newsletterArchive.php under short-circuit analysis, http://www.brainfiller.com/articles/infiniteBusMethod.php

thanks for the help mr. winfield. by the way, do you know faster way but accurate and reliable calculation for short circuit calculations? im trying to compare impedance method versus the calculation use by the software ecodial (quite interesting, hehe) but unfortunately im quite having a hard time for the data that i need to calculate it by the ecodial. thanks again in advance, good day!

and 1 more thing mr. winfield, thanks for the very informative site that you provided. i hope there's a lot more to come.. good day sir!

dear sir

i would like to know about is any need of measuring cu loss in phase wise measurement.since as per relation cu loss depends on current square lets consider that if phase current is different then cu loss are different in different winding of a machine so separate cu loss calculation needed for such a situation.

pls answer

rahu

Winfield Hill Quote " E.g., in your case with a 13.8 kV primary and a 2.5kVA rating, you'd turn up the primary voltage until you get 2.5kVA/13.8kV = 0.181 A of primary current into the shorted transformer (note the units math, VA / V = A). This might happen at about say 80 volts, which would be V*I = 80*0.181 = 15 watts of copper loss at full power. That would be a loss of 15/2.5k = 0.58% at full power, all due to copper, as opposed to core or other losses."

I believe that would be 15 VA and not watts. This is the problem when trying to get the resistance of the windings. The inductance is included in the figures.

Yes, the leakage inductance.

dear sir

i would like to know about is any need of measuring cu loss in phase wise measurement.since as per relation cu loss depends on current square lets consider that if phase current is different then cu loss are different in different winding of a machine so separate cu loss calculation needed for such a situation.

pls answer

rahul

2500 KVA is 2,500,000 VA.

2,500,000 VA is a very large transformer. How are you going to manufacture this transformer?

At this power level and current level, low voltage winding will have to be transposed. If winding is not transposed, copper losses will be excessive.

Do you know how to transpose a winding?

Do you have a person who can wind a transposed winding?

mr. carl, i agree with what you have said regarding 2500 kva transformer but i dont know how this transformer will be manufactured. but i will tell you something, we already used these transformers in some of our projects, to be exact, 8-2500 kva for one building. these transformers were configured in such a way that this electrical infrastructure was certified by Uptime Institute.. Try to search G.E. or Schneider, cast resin transformer, maybe you will able to find your answer from them.. =)

Whew, are you saying the 2500kVA was correct, it's 2.5MVA, and not 2.5kVA? Sheesh! It's one thing to slip a decimal point, it's another to slip three.

nope mr.windfield, its correct 2500 KVA, k13 transformer..=)

WH quote "Whew, are you saying the 2500kVA was correct, it's 2.5MVA, and not 2.5kVA? Sheesh! It's one thing to slip a decimal point, it's another to slip three"

I believe it was you who slipped the 3 dp's. Was that what you meant?

Yes.

Contact the transformer manufacture.

On this size transformer, the manufacture should have the transformer losses.