JEE_V4_N2_RP4 P. Venkata Prasad S. Sivanagaraju Journal on Electrical Engineering 2230 – 7176 4 2 20 27 Distance Protection, Fault Resistance, Line Capacitance, Apparent Impedance, Adaptive Setting, Fourier Transform This paper presents accurate calculation of apparent impedance of transmission lines by distance protection scheme. The apparent impedance equation, considering the transmission line capacitance by utilizing a double p model for a line is derived. The apparent impedance without and with considering the line capacitance is compared by considering the fault resistance. The quadrilateral characteristic of distance relay is compared in both the cases. Simulink model design and adaptive setting for a distance protection with consideration of transmission line capacitance is also investigated using Fourier transform. A 400 kV transmission line with 300km long is used in this study. October - December 2010 Copyright © 2010 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=1273