Single-phase transformer Experiment

1. No-Load Test

N = 10;

U0 = [65.7 60.5 58.5 56.1 54.5 49.3 40.8 30.7 20.2];

I0 = [0.103 0.075 0.066 0.057 0.052 0.040 0.029 0.020 0.014];

P0 = [1.7 1.5 1.5 1.3 1.3 1.1 0.7 0.5 0.3 0];

Uax = [256 235.5 227.5 217.5 210.5 190.0 155.0 115.0 72.5];

% Cosfy0 = p0./ (u0.* I0)

Cosfy0 = [0.253 0.331 0.389 0.407 0.459 0.558 0.592 0.814 1.0 1];

K = sum (uax./U0)/N;

 

Uy = polyfit (I0, U0, 3)

IX = 0: 0. 0001:0. 1;

U = polyval (Uy, IX );

Plot (I0, U0, '*', IX, U)

Grid

Axis ([0 0.1 0 65])

 

Figure

Py = polyfit (U0, P0, 3)

UX = 0: 0. 01: 60;

P = polyval (PY, UX );

Plot (U0, P0, '*', UX, P)

Grid

Axis ([0 60 1.6])

 

Figure

Cy = polyfit (U0, cosfy0, 1)

UX = 0: 0. 01: 60;

C = polyval (CY, UX );

Plot (U0, cosfy0, '*', UX, c)

Grid

Axis ([0 60 0 1])

 

% Calculate the excitation parameters based on the data obtained from the no-load experiment

U0 = 55;

I0 = 0.052;

P0 = 1.2867;

ZM = U0/I0

Rm = P0/I0 ^ 2

XM = SQRT (ZM ^ 2-rm ^ 2)

 

ZM = 1.0577e + 003

Rm = 475.8506

XM = 1, 944.6053

2. Short Circuit Experiment

N = 8;

UK = [25.6 24.5 22.5 20.9 18.3 11.3 7.1 3.7];

Ik = [0.388 0.371 0.340 0.316 0.276 0.171 0.107 0.057];

PK = [4.7 4.3 3.5 3.1 2.3 0.8 0.3 0];

% Cosfyk = PK./(UK. * ik );

Cosfyk = [0.473 0.473 0.458 0.469 0.456 0.414 0.400];

 

Uy = polyfit (Ik, UK, 3)

IX = 0: 0. 001:0. 4;

U = polyval (Uy, IX );

Plot (Ik, UK, '*', IX, U)

Grid

Axis ([0 0.4 0 30])

 

Figure

Py = polyfit (Ik, PK, 3)

IX = 0: 0. 001:0. 4;

P = polyval (PY, IX );

Plot (Ik, PK, '*', IX, p)

Grid

Axis ([0 0.4 0 5])

 

Figure

Cy = polyfit (Ik, cosfyk, 1)

IX = 0: 0. 001:0. 4;

C = polyval (CY, IX );

Plot (Ik, cosfyk, '*', IX, c)

Grid

Axis ([0 0.4 0 1])

 

% Calculate the equivalent drain impedance based on the data obtained from the short-circuit experiment

UK = 23.2;

Ik = 0.35;

PK = 3.78;

In = 0.35;

UN = 55;

K = 3.8;

T = 21.5;

Zk = UK/IK/K ^ 2

Rk = pk/(Ik ^ 2 * k ^ 2)

XK = SQRT (zk ^ 2-rk ^ 2)

Rk75 = rk * (234.5 + 75)/(234.5 + T)

Zk75 = SQRT (XK ^ 2 + rk75 ^ 2)

UK = In * zk75/UN

UKR = In * rk75/UN

Ukx = In * XK/UN

 

Zk = 4.5904

Rk = 2.1369

X k = 4.0627

Rk75= 2.5835

Zk75 = 4.8146

UK = 3.06%

UKR = 1.64%.

Ukx= 2.59%

3. Load lab

U2 = [230 225 223 222 218 217];

I2 = [0 0.15 0.2 0.25 0.3];

Plot (I2, U2 ,'*')

Grid

Axis ([0 0.35 0 250])