Analysis of circuits proposed by CIGRE for excitation of intersheath modes in field testing of normal-bonded cables shows that if the source is grounded, which is usually the case in field tests, different propagation modes arise and it becomes difficult to observe intersheath modes.

The homogeneous model is used to calculate the propagation characteristics of a cross-bonded cable system and to show that inter-core modes change substantially when the cable sheaths are cross-bonded.

Comparison through transient simulation of a discrete and a homogeneous model of a cross-bonded cable makes clear that even though intersheath modes cannot be excited in a cross-bonded cable, they can still be induced by the core conductors and impact the transient response of the cable.

It is shown that the accuracy of a homogeneous model is improved if the number of sheath grounding points is high.