Geometrical Irregularities Effect on Lead Sheathing for Submarine Power Cable Applications

In countries which have to deal with the electrical energy supply to several and small islands, wind farms, oil wells and other users by the sea, a local power production is often not possible, not convenient or with a low efficiency. For these reasons in the last century, and above all in the last decades with a growing interest from the research field, the employment of submarine power cables to provide electrical power to the less accessible users is increasing. After the installation, the main problem for these systems is their life expectation, thus the study of their creep-fatigue behaviour. The life of these cables, which is determined by the most critical layer (the water-blocking Pb sheath) was incremented in several ways: from the alloys’ composition choice to the realization of other layers. In a previous work was demonstrated the beneficial effect of the application of a galvanized steel tape, which limits the radial expansion, thus deformations, owing to the warming up for Joule effect. Despite of that, during its winding, several irregularities arise on the underlying lead sheath and their effect on fatigue life expectation is the main topic of this work. In particular, an irrelevant damaging impact was shown.