ABSTRACT

BIDAYATUL ARMYNAH. The Radial Distribution of Temperature in XLPE Cable: An Analysis Using the Finite Element Numerical Method (supervised by Muhammad Arief and Salama Manjang).

This research investigates the radial distribution of temperature in a type of underground electrical power transmission lines specified as the XLPE cable. The heat produced by the current in the cable is assumed to spread in radial direction throughout the conductor expressed by an elliptic second order differential equation.  The radial structure of the cable is composed of three concentric layers. The innermost layer is the conductor itself with the heat conductivity of k = 398 Watt/mK, while the second and the third layers are assumed to have equal heat conductivity of k = 0.286 Watt/mK. The differential equation is converted into a finite element problem with the ground temperature as the boundary condition and solved numerically using the MATLAB 6.5 program. The result shows that the highest temperature is at the surface area of the conductor, and gradually decreases as the radius increases toward the surface area of the cable, approaching the soil temperature where the cable is buried. The maximum allowable temperature of the XLPE cable is 90oC. Consequently, for a 72.5 kV transmission line, the current must be less than or equal to 640 A for soil temperature of 50 oC, and 800 A for soil temperature of 32oC.