// A Texbook on POWER SYSTEM ENGINEERING // A.Chakrabarti, M.L.Soni, P.V.Gupta, U.S.Bhatnagar // DHANPAT RAI & Co. // SECOND EDITION // PART II : TRANSMISSION AND DISTRIBUTION // CHAPTER 14: LIGHTNING AND PROTECTION AGAINST OVERVOLTAGES DUE TO LIGHTNING // EXAMPLE : 14.1 : // Page number 382 clear ; clc ; close ; // Clear the work space and console // Given data RI_072 = 72000.0 // Charactersistic of lightning arrester Z_c = 500.0 // Surge impedance(ohm) V = 500.0 // Surge voltage(kV) // Calculations // Case(a) V_a = 2.0*V // Voltage at the end of line at open-circuit(kV) ratio_a = V_a/V // Ratio of voltage when line in open-circuited // Case(b) I = V*1000/Z_c // Surge current(A) R = RI_072/(I)**0.72 // Resistance of LA(ohm) ratio_b = R/Z_c // Ratio of voltage when line is terminated by arrester // Results disp("PART II - EXAMPLE : 14.1 : SOLUTION :-") printf("\nCase(a): Ratio of voltages appearing at the end of a line when line is open-circuited = %.f", ratio_a) printf("\nCase(b): Ratio of voltages appearing at the end of a line when line is terminated by arrester = %.f", ratio_b)