Multiphysics FEM Simulation

Grøft Design® (Grøft) provides integrated solutions and user-oriented interface for cable rating calculations. The programs analysis engine is COMSOL Multiphysics®, a simulation software that utilizes the finite element method (FEM). An advantage of the use of the Grøft is a structured and automatized design process of cable systems, without the knowledge of FEM.

Finite Element Method

Finite Element Method (FEM) is a technique used in advanced numerical calculations. FEM approximates with a high accuracy the solution of the complex physical systems in the wide variety of engineering disciplines.

FEM in Cable Rating Calculations

Cable systems modeled in Grøft are represented by complex physical equations, covering areas of physics such as electromagnetism and thermodynamics. The computational model is built based on the geometry of the cables and their surroundings, which can be easily drawn and modeled by the user. The system is solved by applying boundary and reference conditions to the computational domain of the cable system.

Compared to calculations based on the analytical formulas provided by the IEC 60287 standard, FEM models in Grøft offer greater flexibility regarding geometry and boundary conditions. This allows for more accurate results, especially when dealing with complex geometries. Users can introduce various geometrical adjustments, both for cables and trenches, extending well beyond the scope of IEC standards.

To enhance the performance of the computational models, a hybrid method has been implemented for several features, combining FEM models with reliable IEC analytical formulas.

Guidelines for applying the finite element method to cable rating calculations can be found in IEC TR 62095.