Determination of the Ampacity of Buried Cable in Non-Homogenous Environmental Condition by 3D Computation

Abstract

Finite Volume Method (FVM) is chosen to calculate the heat transfer field and the heat generation with in the cable and heat dissipation in the surrounding soil of a three phase 145kV underground cable brunch that make it possible to analyze the ampacity of the cable. FLUENT as the proper software in this field is used to generate and solve the problem. Non-homogenous environment is considered for cable ampacity calculation and results are compare with homogenous environment condition function of the duration of the current circulating in the conductors. There are three standardized ampacity ratings: steady state, transient (or emergency) and short-circuit. Only steady state ampacity ratings are discussed in this paper. As providing analytical solution for complex situation is very indirect and in many cases the experimental method may preferred, in these condition numerical method as FVM is more pragmatic and cost effective. This paper focuses on the numerical techniques for the computation of cable ampacity in steady-state through the use of assumptions that simplify the problem. Finite Volume Method (FVM) is chosen to calculate the heat transfer field and heat generation with in the cable and heat dissipation in the surrounding soil. FLUENT as a proper software in this field is used to generate and solve the problem, FLUENT 6.3 (13). Most of the researches in this field are for homogenous area (soil) condition in order to simulate the actual soil in this paper a three dimensional model of the cable in full size and non-homogenous surrounding area is designed in FLUENT. Results are compared with the homogenous area condition.