Introduction: High voltage terminations are essential components in high voltage cable systems. Great reliability is provided by high manufacturing quality and company type testing. However onsite installations represent a considerable uncertainty for successful service of the system. Commissioning testing of cable systems according to IEC60840 and IEC62067 should allow a safe, undisputed service. The cable can be put into service after successfully passing a commissioning test, which is increasingly accompanied by partial discharge measurement. While acable is in service, periodically performed offline testing and diagnostic measurements rarely take place due to the significant effort of switching off the cable system. Online diagnostic methods, which could be used whilst a cable is in service, are valuable sources for information and represent a reasonable compromise between costs and benefit. UHF PD Diagnosis has proven to be a valuable and effective method for measuring high voltage assets (cables, GIS, transformer), because this online measurement is performed at frequencies which are not affected by environmental noise.
