## Voted Best Answer

Jul 03, 2015 - 12:26 AM

Hi,

in order to model any transformer using 3 phase 2 winding transformer model, you normally need the parameters given in the transformer nameplate (with some modifications).

As for the parameters you ask about, positive sequence leakage reactance is the per unit value of short circuit test voltage (sometimes named as Uk), in your case 5/100 = 0.05.

No load losses and magnetizing current are determined during open circuit test and correspond to the parallel branch in the transformer model, but I guess you don't have the relevant data. As base apparent power PSCAD uses the transformer apparent power.

The same applies to copper losses, but you don't have copper losses, only R/X ratio, so if you need to include R in your model, you need to calculate the losses using the formula R=(Pk/Sn)*(U^2/Sn), where Pk - losses in physical units, Sn - transformer rating, U - voltage.

UMEC transformers are explained in PSCAD help, you can use them for example for modelling 3-limb three-phase transformers (3 phase 2 winding transformer model is basically based on 3 single phase units).

Cheers,

Marcin

in order to model any transformer using 3 phase 2 winding transformer model, you normally need the parameters given in the transformer nameplate (with some modifications).

As for the parameters you ask about, positive sequence leakage reactance is the per unit value of short circuit test voltage (sometimes named as Uk), in your case 5/100 = 0.05.

No load losses and magnetizing current are determined during open circuit test and correspond to the parallel branch in the transformer model, but I guess you don't have the relevant data. As base apparent power PSCAD uses the transformer apparent power.

The same applies to copper losses, but you don't have copper losses, only R/X ratio, so if you need to include R in your model, you need to calculate the losses using the formula R=(Pk/Sn)*(U^2/Sn), where Pk - losses in physical units, Sn - transformer rating, U - voltage.

UMEC transformers are explained in PSCAD help, you can use them for example for modelling 3-limb three-phase transformers (3 phase 2 winding transformer model is basically based on 3 single phase units).

Cheers,

Marcin

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