Calculation of ampacities for cables in trays using finite elements

This paper describes a finite element method for calculating the ampacities of cables in a tray. The governing equation is solved using Galerkin's procedure and the Newton-Raphson iterations is employed to solve nonlinear finite element equations as a result of the inclusion of radiation boundary conditions. The use of an equivalent thermal conductivity of cable mass in a tray is proposed. To determine the cable derating factor, both open-top and covered cable tray are employed in the analyzed model. It can be seen that the cable derating factor is independent of the type cables filled in the tray. The numerical results of this method are good and comparison with other available values. (C) 2000 Elsevier Science S.A. All rights reserved.