//Book - Power system: Analysisi & Design 5th Edition //Authors - J. Duncan Glover, Mulukutla S. Sarma, and Thomas J.Overbye //Chapter-3 ;Example 3.5 //Scilab Version - 6.0.0; OS - Windows clc; clear; Eab=480 //Line voltage of star connected voltage source in Volts ZL=10*exp(%i*40*%pi/180) // Load impedance in Ohms Zl=1*exp(%i*85*%pi/180) // Line impedance between source and load in Ohms Sb=10 //Base power in kVA VbLL=480 //line to line base voltage in Volts Zb =((VbLL)^2/(Sb*1000)) //Base impedance in Ohms Zlpu=Zl/Zb //per unit line impedance ZLpu=ZL/Zb //per unit load impedance VbLN=VbLL/(sqrt(3)) //line to neutral base voltage in Volts Eanpu=(277*exp(%i*(-30)*%pi/180))/277 //source voltage in per unit Iapu=Eanpu/(Zlpu+ZLpu) //per unit line current in phase a Ib=(Sb*1000)/(sqrt(3)*VbLL) //base current in Amperes Ia=Iapu*Ib //actual phase a line current in Amperes printf('The magnitude of per unit line current in phase a is %.4f and its angle is %.4f degree\n',abs(Iapu),atand(imag(Iapu),real(Iapu))); printf('The magnitude of actual line current in phase a is %.4f Amperes and its angle is %.4f degrees\n',abs(Ia),atand(imag(Ia),real(Ia)));