10 kVA 200/400 V LV-side parameters

Given: 10 kVA, 200/400 V. OC test on LV side: 200 V, 1.3 A, 120 W. SC test on the HV side (HV supplied, LV shorted): 22 V, 30 A, 200 W. Turns ratio K = 400/200 = 2.

Shunt branch (LV side, directly from OC test)

cos φ0 = 120/(200 × 1.3) = 0.4615
Iw = 1.3 × 0.4615 = 0.600 A ;  Iμ = √(1.3² − 0.6²) = 1.153 A
Ro = 200/0.600 = 333.3 Ω ;  Xo = 200/1.153 = 173.4 Ω

Series branch

SC on the HV side gives the parameters referred to the HV side:

Z02 = 22/30 = 0.7333 Ω ;  R02 = 200/30² = 0.2222 Ω
X02 = √(0.7333² − 0.2222²) = 0.6989 Ω

Refer to the LV side by dividing by K² = 4:

R01 = 0.2222/4 = 0.0556 Ω
X01 = 0.6989/4 = 0.1747 Ω
Z01 = 0.7333/4 = 0.1833 Ω

Equivalent circuit referred to the LV side

  I1     R01=0.0556Ω  X01=0.1747Ω       I2'
 o──┬─────┬──────/\/\/───────(((─────────o
    │     │                              
   Ro    Xo                         load
 333.3Ω 173.4Ω                       V2' = V2/2
    │     │                              
 o──┴─────┴──────────────────────────────o

Answer: shunt branch Ro = 333.3 Ω, Xo = 173.4 Ω; series branch R01 = 0.0556 Ω, X01 = 0.1747 Ω, all referred to the LV (200 V) side.