// A Texbook on POWER SYSTEM ENGINEERING // A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar // DHANPAT RAI & Co. // SECOND EDITION // PART III : SWITCHGEAR AND PROTECTION // CHAPTER 7: PROTECTIVE RELAYS // EXAMPLE : 7.6 : // Page number 611 clear ; clc ; close ; // Clear the work space and console // Given data I_min = 0.1 // Relay minimum pick up current(A) slope = 10.0 // Slope characteristic(%) CT_ratio = 400.0/5 // CT ratio I_1 = 320.0 // Current(A) I_2 = 304.0 // Current(A) // Calculations I_op_coil = (I_1-I_2)/CT_ratio // Current in operating coil(A) I_re_coil = 1.0*(I_1+I_2)/(2*CT_ratio) // Current in restraining coil(A) I_re_coil_slope = I_re_coil*slope/100 // Current in restraining coil with slope(A) // Results disp("PART III - EXAMPLE : 7.6 : SOLUTION :-") if(I_op_coil