//Book - Power System: Analysis & Design 5th Edition //Authors - J. Duncan Glover, Mulukutla S. Sarma, and Thomas J. Overbye //Chapter - 14 ; Example 14.1 //Scilab Version - 6.0.0 ; OS - Windows clc; clear; Vdelpri=230; //The rated RMS line voltage of the primary winding in kV Vwyesec=34.5; //The rated RMS line voltage of the secondary winding in kV MVAoa=75; //The MVA OA rating of the transformer MVAfa=100; //The MVA FA rating of the transformer MVAfoa=133; //The MVA FOA rating of the transformer Zpu=0.07; //The percentage impedance of the transformer in terms of MVA OA ratings MVAbase=100; //The MVA base in MVA kVbase=34.5; //The KV base in kV Ioa=(MVAoa/3)/(Vwyesec/sqrt(3)); //The OA transformer current in the low voltage side in kA Ifa=(MVAfa/3)/(Vwyesec/sqrt(3)); //The FA transformer current in the low voltage side in kA Ifoa=(MVAfoa/3)/(Vwyesec/sqrt(3)); //The FOA transformer current in the low voltage side in kA Zbasepu=Zpu*MVAbase/MVAoa; //The per unit impedance of the system in ohm pu Isc3ph=(1/Zpu)*Ioa; //The transformer current during three phase bolted faultin kA printf('\nThe OA transformer current in the low voltage side is %f kA',Ioa); printf('\nThe FA transformer current in the low voltage side is %f kA\n',Ifa); printf('The FOA transformer current in the low voltage side is %f kA\n',Ifoa); printf('The per unit impedance of the system is %f pu\n',Zbasepu); printf('The transformer current during three phase bolted fault is %f kA',Isc3ph); //The answer in the book is not correct. Eg.75/(sqrt(3)*34.5)---Actual result is 1.255, but it is given as 7.372 in the book.