• Given a three-phase power system with a medium-length transmission line, calculate the sending-end voltage and current by hand and by using Matlab code.

Trial>> %M-file to calculate the sending end voltage and current for a medium-length transmission line. Trial>> %Initialize received voltage, impedance, and admittance Trial>> vr = 12700 ; Trial>> z = 0.1 + j*0.82; Trial>> y = j*4.00e-3; Trial>> %Calculate ABCD constants Trial>> A=z*y/2 + 1; Trial>> B=z; Trial>> C=y * (z*y/4 + 1); Trial>> D=z*y/2 + 1; Trial>> %Calculate the sending end voltage Trial>> ir = pol2cart(393.65,5.28); Trial>> vs = A * vr + B * ir; Trial>> [mag,phase] = cart2pol(vs); Not enough input arguments.

Error in cart2pol (line 21) th = atan2(y,x);

[Tamir Suliman]

please format your post correctly or upload your m file script

Answer 1

[Tamir Suliman]

You will have to add more details from the problem like for example S value how did you arrive to Ir values to convert

This is an example on how to solve a problem liket his

You will have to look at the help functions for the poly2cart and cart2poly

clc,clear
vr = 12700;
z = 0.1 + j*0.82; % Perphase series impedance 
y = j*4.00e-3; %The per-phase shunt admittance 

%%The ABCD constants for a medium length line

A=z*y/2 + 1;
B=z; 
C=y*(z*y/4 + 1); 
D=z*y/2 + 1;

% The rated line voltage is 12.7Kv  so the rated phase voltage 
%is 12.7 Kv/Sqrt(3)  
[sd ir] = pol2cart(393.65,5.28);
Vr = 7.3323e3;
Ir=sd+ir*j;

Vs=A*vr+B*Ir;
X=real(Vs)
Y=imag(Vs)

[mag,phase] = cart2pol(real(Vs),imag(Vs))