Earth return admittance impact on crossbonded underground cables

Typically, the modeling of underground cables systems for electromagnetic transient simulations is carried out disregarding the effects of the ground return admittance. However, recent studies have presented precise models for the representation of the earth return admittance and demonstrated the importance of considering its effects on transient overvoltages along the cable and at sheaths crossbonding, especially if short minor sections are involved. In this paper, a study on the effects of the ground return admittance when considering an underground cross-bonded cable system is presented for 1 km and 300 m for the minor section length where the effects of earth return admittance are to be more pronounced. The inclusion of the ground-return admittance leads to a higher damping, which indicates that the conventional approach may lead to over conservative results.