How to get the phase angle from Three Phase Power System

Hello, currently an MSc student, have a tutorial problem with three phase power this is the question

Generator phase voltages: 𝑉𝑃1=220∠0𝑜 𝑉,𝑉𝑃2=220∠120𝑜 𝑉,𝑉𝑃3=220∠240𝑜 𝑉

Already done the calculation on paper and using the calculator to get the answers. Nevertheless trying to figure out how to do it in Matlab how to get this answer ∠??𝑜

Doing the equations the answer I have for the V on the load end is 381.05 ∠-30 for (VP1 - VP2) but before that the complex number is 330 + j190.52 (how do you get the ∠30 or 210 or 90) I know you can use

Magnitude = abs(z)

Phase = angle(z)

and then using cos and sin however do not get the -30 or 210 value. Unless I am doing something wrong to find this angle or there is a simplier way?

Answer 1

[Shivam]

Hi Daniel,

From the information you provided, I understand that given three phasors of a 3-phase power system, you want to calculate the phase angle between two phasors (here, VP1 and VP2) in MATLAB.

You can follow the below workaround to calculate the phase angle between two phasors:

% Given phasor
VP1 = 220 * exp(1i * deg2rad(0));     % VP1: 220∠0°
VP2 = 220 * exp(1i * deg2rad(120));   % VP2: 220∠120°
VP3 = 220 * exp(1i * deg2rad(240));   % VP3: 220∠240°

VP1_diff_VP2 = VP1-VP2;  

% Calculate the angle of the phasor: VP1 - VP2
angle_rad = angle(VP1_diff_VP2);

% Convert the angle to degrees
angle_deg = rad2deg(angle_rad);
disp(angle_deg);

  -30.0000

You can refer to the following documentation to learn more about 'angle': https://www.mathworks.com/help/releases/R2023a/matlab/ref/angle.html

I hope it helps.