Transient analysis of a cable with low-conducting layers by a finite-difference time-domain method

The impedance and admittance formulas of a cable with low-conducting layers have not yet been derived, and thus a transient analysis considering the layers cannot be carried out sufficiently by an existing transient analysis program such as the Electro-Magnetic Transients Program. The present brief has analyzed a transient response of a power cable including low-conducting layers using a finite-difference time-domain method. Transient current waveforms at both ends of the cable are distorted depending on the conductivity of the low-conducting layers. Also, the propagation velocity of a surge current is dependent on it. When the conductivity of low-conducting layers is around 10/sup -3/ S/m, the shunt admittance of the cable dominates the above phenomena. On the other hand, they are ascribable to the series impedance when the conductivity is about 10 S/m.