Application of finite element simulations for cable installations.

Summary

The design and specifications of buried power cables require that standard conditions applicable globally be followed. The steady state current rating of power cables are given in IEC 60287 standard and the cyclic or emergency ratings are given in IEC 60853. Certain assumptions, which are not representative of the actual conditions, are made in the standards to accommodate the use of mathematical equations. The use of computer simulation software opened the door for the calculation of current ratings under real installation conditions and variables can be incorporated in the simulations resulting in more accurate results. No standards exist for developing the cable models used in computer simulations and it is therefore important to still use a reference to which the computer simulation model can be compared. This paper describe the procedure to develop a model used with Finite Element Simulation software to give the same results as would be obtained using the mathematical procedures in IEC standards. The procedure involves firstly generating the cable model and then solve it using the same assumptions regarding boundary conditions and heat flow as described in the IEC standards. The model will also determine the mesh spacing to be used. The second procedure is to apply the cable model to real installation conditions (depth of burial) and determine the boundary distances and conditions as well as the mesh spacing to achieve the same results as with the IEC procedures. The difference in results between the simulation results according to the IEC model and real installation conditions where the soil surface is not assumed to be an isotherm are also presented. The final outcome in the paper is to demonstrate the transient temperature rise using the proposed models.

Additional informations

Keywords

Power Cables, Installation Conditions, Finite Element Simulations, Accuracy, Model