Transformer X/R Calculator

Calculate per-unit resistance (R) and reactance (X) values from transformer nameplate data for network modelling and short circuit analysis.

Transformer Nameplate Data

Calculated Values

Resistance (R)
- p.u.
Reactance (X)
- p.u.
X/R Ratio
-

Additional Values

Impedance (Z) - p.u.
Base Impedance - Ω
R (ohms, HV side) - Ω
X (ohms, HV side) - Ω

Calculation Method

Per-Unit Resistance:

R = PCu / Srated

Where PCu is copper losses in MW and Srated is MVA rating

Per-Unit Reactance:

X = √(Z² - R²)

Base Impedance:

Zbase = V² / S

Where V is in kV and S is in MVA

Actual Impedance:

Zactual = Zp.u. × Zbase

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