“Whatever the nature of the fault, if an underground cable fails, the necessary repairs take around 20 days on average. Six days alone are taken up with searching for and pinpointing the location of the actual cable fault. This leads to high downtime costs”, explains Dan Keller, Sales Manager Utility Business at HIGHVOLT. This is exactly where HiMON® comes in. The modular service package for quality assurance and condition assessments of HVDC underground cables provides a perfect combination of sensors and software that complement each other. HiMAG® sensors and the corresponding digitalizsation unit HiRES Locator are installed at every cable station that connects the individual cable sub-sections. Thanks to the way the sensors are distributed all along the entire cable section, faults can be immediately detected and localised. So, if a customer has chosen to use this new system, their service engineers are able to quickly and accurately pinpoint where the repairs need to be carried out.
HIGHVOLT is currently testing the second feature of the service package, which will be used to identify potential problem areas before failure of the cable system occurs. Although partial discharges do not always cause the cable system to fail, they often indicate sources of faults. Consequently, the second feature also includes special sensors capable of detecting even the tiniest partial discharges. These sensors are installed at distances of 12 km along the length of the cable, resulting in minimal installation requirements. The corresponding digitalization unit and the TruePD software employ intelligent algorithms to calculate the likelihood of failures from the sensor data and offer forward-looking service recommendations even before a problem occurs. HiMON® also includes an Intelligence Cluster – an expert system in which all the data is pulled together ready for checking and analysis at any time. “In terms of the HVDC projects that are planned, we are looking at cables that are several thousands of kilometres long. The need to be able to centrally monitor as closely as possible such huge distances with minimal installation effort is completely new for the market”, emphasises Keller.