Earth faults in medium voltage cables and the electrical interference in the vicinity of swimming pools

In the case of earth faults on medium-voltage cables, potential rises and thus step and touch voltages can occur in the immediate vicinity of the fault location due to the injection of currents into the ground. These must be considered with regard to personal safety. A special situation arises if the fault location occurs in the vicinity of a swimming pool, since people can be barefoot here. The smaller contact resistances to the ground than those with footwear lead to larger body currents. This situation is assessed in terms of its hazard potential, considering the relevant standards.

The focus of this paper is on the question of the conditions under which the proximity of a swimming pool to a buried cable can result in a hazard to persons in the event of an earth fault in compensated medium-voltage networks (20 and 30 kV), and what measures should be taken by operators of these cables if necessary.

Two different fault scenarios are analyzed in detail, a cable fault in the vicinity of a swimming pool and a fault in the area of a cable transition tower with transferred potential via the cable accompanying earth electrode.

The main parameters influencing the fault current are investigated with respect to the effects on step and touch voltages.

The investigations show that in most of the fault scenarios considered, no hazard is to be expected for persons with regard to step and touch voltages.


Investigated touch-scenarios in vicinity of a cable with earth fault, touch voltages in push-up-position and step voltages

DOI: https://doi.org/10.1007/s00502-022-00995-5

Download Paper: https://link.springer.com/content/pdf/10.1007/s00502-022-00995-5.pdf