High voltage insulation diagnosis for lifetime management

Advanced partial discharge (PD) analysis methods have been evaluated on their availability as input for lifetime management systems in the field in order to obtain a better assessment of warning conditions for HVAC and HVDC components. It is shown that AC-PD detection by VHF/UHF measurements provide a practical way for identification and location of defects as well as recognition of ageing processes in several components. Utilization for the benefit of diagnostic maintenance or lifetime management becomes of practical interest in case of HV cable systems, turbogenerators and power transformers, while GIS needs further development. For HVDC equipment a new DC PD analysis technique on basis of the discharge sequence has been developed, which applies well in practice to check or monitor the condition in case of PD-induced ageing effects