Abstract :
The voltage distribution along the power cable cores and sheaths determines the insulation stress and the compliance with certain operational specifications defined by the international standards. Calculations of voltage profiles in cable arrangements using cascaded frequency-dependent modalor phase-domain models may lead to error accumulations. Direct time-domain transmission line models using the Finite-Difference Time-Domain (FDTD) method can accurately calculate voltages and currents with a high spatial discretization along cable cores and sheaths. However, frequency-dependent FDTD models have been proven either significantly slow in computations or numerically unstable, whereas their application in underground cables is also limited. In this paper, an FDTD model is formulated for power cables with distributed constant parameters, taking into account the influence of the skin-effect and the imperfect earth. The proposed model provides accurate transient and steady-state responses in single-phase and multiphase overhead and underground cable arrangements. Sheath cross-bondings can be also handled by the proposed formulation. The model can also provide transient and steady-state voltage profiles along cables, useful in insulation coordination or power-line communication signal analysis studies.
