Aging of oil impregnated paper due to Pd activity
2013 (English)Conference paper (Other (popular science, discussion, etc.))
Air filled cavity may appear inside solid insulation either due to bad manufacturing or as a result of insulation ageing. A cavity is a weak point in insulation and if the electric stress is high enough; partial discharge can be initiated inside the cavity. In this paper changing of PD parameters (number of PD, maximum magnitude of PD and average magnitude of PD) was investigated over time on oil impregnated paper with an artificial cavity in between the sheets of paper. PD parameters were recorded from the inception of PD until final puncture breakdown occurs in the sample. Experiment was performed on sample with different thickness. Specific pattern on changing of PD number and maximum magnitude of PD was observed for most of the experiments. The pattern includes three stages, big discharges appear at inception of PD and over a very short time they disappear. At stage two, the number and magnitude of PD increase rapidly from small values until they reach to a maximum value. At stage three, the number and magnitude of PD decreases and reach to a constant value. The PD parameter keep constant until the time that final breakdown occurs. The dielectric spectroscopy performed on the sample before and after exposure to PD shows that PD activity causes a permanent shift on ε" which can be explained by PD by-products.
Place, publisher, year, edition, pages
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-136428OAI: oai:DiVA.org:kth-136428DiVA: diva2:676099
18th International Symposium on High Voltage Engineering, August 25th-30th 2013, Seoul, South Korea
QC 201312192013-12-052013-12-052015-02-06Bibliographically approved