blob: 135a12fb6b472f2b4934473df92903a719dc2963 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
// Example 2.14
// Determine (a) Magnetizing reactance and equivalent core-loss resistance
// (b) Per unit resistance, reactance and impedance of transformer windings
// (c) Voltage regulation when operating at rated load and 0.75 power factor lagging
// Page No. 78
clc;
clear;
close;
// Given data
Poc=521; // Open circuit test power
Voc=230; // Open circuit voltage
Vo=230; // Output voltage
Ioc=13.04; // Open circuit current
Vsc=160.8; // Short circuit voltage
Isc=16.3; // Short circuit current
Psc=1200; // Short circuit power
S=75000; // Transformer rating
Vhs=4600; // High side voltage
FP=0.75; // Power factor lagging
// (a) Magnetizing reactance and equivalent core-loss resistance
Ife=Poc/Voc; // Current rating
RfeLS=Vo/Ife; // Core-loss resistance
Im=sqrt(Ioc^2-Ife^2); // Magnetizing current
XMLS=Voc/Im; // Magnetizing reactance
// (b) Per unit resistance, reactance and impedance of transformer windings
ZeqHS=Vsc/Isc; // Equivalent impedance
ReqHS=Psc/Isc^2; // Equivalent resistance
XeqHS=sqrt(ZeqHS^2 - ReqHS^2); // Equivalent reactance
Ihs=S/Vhs; // High side current
RPU=Ihs*ReqHS/Vhs; // Per unit resistance
XPU=Ihs*XeqHS/Vhs; // Per unit reactance
ZPU=RPU+%i*XPU; // Per unit impedance
// Complex to Polar form...
ZPU_Mag=sqrt(real(ZPU)^2+imag(ZPU)^2); // Magnitude part
ZPU_Ang=atan(imag(ZPU),real(ZPU))*180/%pi; // Angle part
// (c) Voltage regulation when operating at rated load and 0.75 power factor lagging
// Transformer regulation
Theta=acosd(FP);
RegPU=sqrt( (RPU+FP)^2 + (XPU+sind(Theta))^2 )-1;
// Transformer regulation in percentage
RegPU_Per=RegPU*100;
// Display result on command window
printf("\n Equivalent core-loss resistance = %0.1f Ohm",RfeLS);
printf("\n Magnetizing reactance = %0.2f Ohm", XMLS);
printf("\n Per unit resistance = %0.3f ", RPU);
printf("\n Per unit reactance = %0.3f ", XPU);
printf("\n Per unit impedance magnitude = %0.3f ", ZPU_Mag);
printf("\n Per unit impedance angle = %0.1f ", ZPU_Ang);
printf("\n Voltage regulation in percentage = %0.2f ", RegPU_Per);
|
