Challenges and safety aspects for effective fault location on long HVAC and HVDC cables

Long cables are now in the spotlight as a means of power transmission and distribution and are quite crucial both for building the European supergrid and for driving the green energy transition towards renewable generators. As has been unsightly demonstrated repeatedly in recent years, these long cables are much more fragile than expected, and outages caused by cable faults show significant negative impacts on the security of supply and the economics of operating resources. The problem is not expected to diminish given the exponential addition of offshore wind generation worldwide and due to HVDC corridor projects such as Südlink or SüdOstLink. Such cable routes, especially transnational interconnectors, which are mainly HVDC cables, therefore require an approach adapted to the problem. Faults must be measured as quickly as possible so that they can be repaired and reconnected in a timely manner. In contrast to the conventional medium-voltage cables of the distribution networks, however, fault location on long cables cannot utilize the same equipment utility companies and service contractors use on medium-voltage cables.