Interpretation of PRPD Pattern Dr. Kay Rethmeier Rene Hummel Ole Kessler © OMICRON Academy 10 April 2011 Corona discharges on high voltage potential Corona discharges on ground potential Corona Discharges on Ground Potential with Multiple Reflections (HV Cable) © OMICRON Academy Void Discharges in Solid Dielectric Material some single cavaties © OMICRON Academy Void Discharges – Micro-Voids bigger cavaties © OMICRON Academy Some Single Voids Bow structure in both half cycles, similar amplitude if cavity is in the center of the dielectric layer. © OMICRON Academy Void Discharges in XLPE Cable, Early Stage © OMICRON Academy Void Discharges in XLPE Cable, Developing Fault © OMICRON Academy Void Discharges in XLPE Cable, Further Developing Fault © OMICRON Academy Cable PD, Defective Outer Semicon Layer © OMICRON Academy Bubble in Oil Pattern is disappearing and re-appearing from time to time © OMICRON Academy Surface Discharges © OMICRON Academy Surface discharges - significant differences in amplitude © OMICRON Academy Surface discharges, significant differences in amplitude, and in PD repetition rate pattern is 3 times higher in one half wave, but a symmetric pattern © OMICRON Academy Contact PD when the bad contact becomes better, the contact PD disappears © OMICRON Academy Floating Potential © OMICRON Academy Delamination on outer semicon PD Patterns and Classification Source: J. Fuhr, Procedure for Identification and Localization of PD, IEEE Transactions 2005 PD Patterns and Classification > 20 Source: J. Fuhr, Procedure for Identification and Localization of PD, IEEE Transactions 2005 PD Patterns and Classification CIGRE WG 21.03 Recognition of Discharges © OMICRON Academy
