Ampacity Analysis of Buried Cables Based on Electromagnetic-thermal Finite Element Method

Ampacity of cable system is crucial for cable project design and electric power supplementation. Owing to the heat-resistance property of the material, temperature distribution is the key point of cable capacity, and it is a coupling problem which involves the electromagnetic-thermal multi-physics fields. To solve this problem, the finite element method was studied, and compute program is developed by the authors which contains the modeling, meshing, calculation and results displaying. Cables could be modeled in layering way and Delaunay triangularization is adopted to gain good meshing grids which can satisfy the calculation of cable system. Dichotomy is used to search the cable ampacity and the coupling program will iterate automatically to gain the current when the highest cable conductor temperature is 90°C. Temperature distribution on nodes is shown in point style and the results show that the errors against the results calculated using IEC60287 is small, and the proposed method can compute the ampacity of buried cable system well.