Thursday, August 12, 2010

Studying The Charecteristics of a Transmission Line by MATLAB Programming

M-File Programming for Transmission Line:

clc

clear

disp('STUDYING THE CHARECTERISTICS OF A TRANSMISSION LINE')

disp('***************************************************')

disp(' ')

V=input('Receiving end line voltage in volt =');

L=input('length of transmission line in km =');

Pr=input('Rated power at receiving end load =');

pf=input('power factor=');

I=Pr/(sqrt(3)*V*pf);

a1=acos(pf);

Vr=V/sqrt(3)

Ir=I*cos(a1)-j*I*sin(a1)

r=input('resistance/km/phase=');

x=input('inductive reactance/km/phase=');

R=r*L;

X=j*x*L;

Z=R+X

if V>20000

y=input('capacitive susceptance/km/phase=');

Y=j*y*L

m=Y*Z;

end

if V<20000

disp('SHORT TRANSMISSON LINE')

disp('**********************')

A=1

B=Z

C=0

D=A

end

if V>20000 & V<100000

disp('MEDIUM TRANSMISSIOM LINE')

disp('************************')

disp(' ')

A=1+m/2;

T=1;

Py=2;

g=input('choose nominal T or Py model=');

if g<2

disp('nominal T model')

disp('***************')

A

B=Z*(1+m/4)

C=Y

D=A

end

if g>1

disp('nominal Py model')

disp('****************')

A

B=Z

C=Y*(1+m/4)

D=A

end

end

if V>100000

disp('LONG TRANSMISSION LINE')

disp('**********************')

n=sqrt(Z/Y);

o=sqrt(m);

A=cosh(o)

B=n*sinh(o)

C=sinh(o)/n

D=A

end

Vs=A*Vr+B*Ir

Is=C*Vr+D*Ir

reg=(abs(Vs)-Vr)*100/Vr

Vs_line=sqrt(3)*Vs

Ps=3*(real(Vs*Is))

eff=Pr*100/Ps


(try it)