Transformer kVAr Losses

Other variables are probably more important.

"...kVAr losses...", now that's a curious juxtaposition of words. Losses are measured in kW not kVAR. What exactly are you referring to?

As RAMconsult already said, the reactive power-or the apparent power also-it isn't a "real power" then the "losses" notion it is a nonsense. But, if you will measured the power factor upstream the transformer and downstream you'll see

the transformer "adds" a reactive power to the loaded power at secondary terminals. You may see this reactive power as a "losses". Since it depends on the transformer leakage reactance Q=I^2*Xs then if the current stays constant -and X=2*pi()*freq*L these "losses" will be 60/50 times more at 60 Hz [Nevertheless L-the inductance- slightly depends on supply voltage].

thanks for reply

I was refering to the kVAr requirement at 50 hz and 60 hz of the transformer

definitely not

In AC the effective power is the difference between the kVA and kW dependent on power factor. This difference of input power kVA and output kW is termed as kVAR ( Reactive power) or the apperent loss due to power factor. With unity power factor the kVA is equal to kW and kVAR is zero. So kVAR depends only on cos Φ which is related to Inductance and Capacitance of the circuit involved. What ever effect the frequency has on inductive reactance and Capacity reactance on the circuit will have the same effect while calculating the kVAR loss on transformers between 50 Hz and 60 Hz.