Double layered sheath in accurate HV XLPE cable modeling

Abstract

This paper discusses modelling of high voltage AC underground cables. For long cables, when crossbonding points are present, not only the coaxial mode of propagation is excited during transient phenomena, but also the intersheath mode. This causes inaccurate simulation results for high frequency studies of crossbonded cables. For the intersheath mode, the correct physical representation of the cables sheath as well as proximity affect play a large role and will ensure correct calculations of the series impedance matrix and therefore a correct simulation for the actual cable. This paper gives a new, more correct method for modelling the actual physical layout of the sheath. It is shown by comparison to field measurements how the new method of simulating the cable's sheath results in simulations with less deviation from field test results.