Papers
Hybrid Method for Numerical Implementation of Segmented Power Cable Conductors in Finite-element Based Ampacity Calculation
Abstract
This paper addresses challenges with modelling of segmented power cable conductors using finite element analysis (FEA) for ampacity calculation. Segmented conductors improve current distribution by minimizing skin and proximity effects, thus reducing conductor losses. 2D FEA simulation offers high flexibility and accuracy beyond IEC 60287 for complex laying geometries, but the modelling of losses in segmented constructions using FEA has proven difficult due to the big difference in wire size and twisting pitch, requiring great amounts of computational power. In this paper a hybrid method is proposed, in which the IEC 60287 empirical formulae for segmented conductors are included in a 2D FEA model. The proposed method shows a good correspondence to IEC standard calculations, with deviations in conductor AC resistance of less than 1 %.
Conclusion
The primary goal of this work was to develop a simplified and practical method for implementing segmented conductors in 2D FEA based power cable ampacity calculations. The model should accurately reproduce the losses in the conductor compared to IEC standard calculations, while preserving the flexibility of FEA with regards to complex laying geometries.
The main conclusions that can be drawn from the analysis of this paper are the following:
- The proposed method consists of a hybrid between a FEA based cable model and the IEC standard formulae for Milliken conductors.
- The results of the proposed method match up well with the IEC standard, with relative differences in both RAC and conductor losses of less than 1 %.
- The relative difference in maximum conductor temperature in 2-pt bonding is most likely not due to the modelling of the segmented conductor itself, but rather the losses in the screen. This needs further investigation.