A failure of a high voltage power cable causes a service
interruption, costly location, repairs and loss of revenues.
Modern plug-in cable connectors (terminations) for GIS and
transformers are made from silicone rubber. The electrical life
span of this high polymeric material normally exceeds
40 years, but only in absence of partial discharge (PD) activity
that inevitably causes material degradation. Several IEC
standards prescribe routine tests on the prefabricated
components of HV cable accessories to be carried out by
manufacturers. The conventional IEC 60270 method, which
can be calibrated, is always applied during quality assurance
testing on the components in the factory in those cases. An
inaccurate assembly done under on-site conditions can
strongly affect the long-term performance of the complete
accessory. Therefore, to make sure that the assembly was done
properly, a quality check on-site is often desired by utilities.
Partial discharge detection is a well established criterion for
the condition assessment and quality control of the high
voltage electrical insulation. The occurrence of PD in
electrical insulation is always associated with the emission of
electromagnetic pulses. A typical PD pulse has a rise time of
less than 1 ns and a width of a few ns, implying in frequencydomain
a bandwidth of several hundreds of MHz. The ultrawide
band PD (UHF PD) diagnosis is based on capturing
those pulses. This method yields higher signal-to-noise ratio
under on-site conditions comparing to the conventional IEC
602070 PD measurement