On Site PD-Diagnosis of Power Cables using the Oscillating Voltage Method

PD testing is an important tool for the asset management in terms of reliability of medium voltage cable networks and maintenance decisions. The quality control of cable installations by PD measurements will become increasingly important in the future, because the increasing cost pressure upon the network operators to reduce installation cost. For the evaluation of PD occurrences, the PD inception and extinction voltages and the local concentration of PD have to be considered as the most important parameters besides the trend or preset levels of PD. Statements regarding the remaining life time of a cable are generally not possible via the PD diagnosis nor are they with any other diagnostic method. However, an evaluation based on practical experience permits to perform a risk assessment regarding the condition and reliability. The PD diagnosis provides valuable information for required maintenance activities and helps to spend available budgets prudently