Dielectric Frequency Response of Oil-impregnated Paper: the Effect of Partial Discharges Compared to other Influences
2016 (English)In: IEEE transactions on dielectrics and electrical insulation, ISSN 1070-9878, E-ISSN 1558-4135, Vol. 23, no 3, 1769-1777 p.Article in journal (Refereed) Published
In this paper, the influence of partial discharges (PD) on the subsequent dielectric properties of oil-impregnated paper (OIP) is investigated. Dielectric frequency response (DFR) of OIP is investigated at varied levels of moisture, thermal aging, temperature, oil conductivity and electrode material, to allow comparison of these influences. It is shown that PD activity inside OIP can significantly change the real and imaginary parts of permittivity of the paper layers, especially in the frequency range below 100 Hz. It is shown that even if the PD activity is concentrated on a few percent of the test sample, the real part of permittivity measured on the entire sample after a few tens of hours of PD activity can increase up to 10 times at very low frequencies (similar to 1 mHz) and the imaginary part of the permittivity can increase up to 100 times at low frequencies (similar to 1 Hz). The change of the real and imaginary parts of permittivity due to PD activity is permanent. It is very similar to the change caused by thermal aging, and somewhat similar to the change caused by moisture and higher oil conductivity. It is also shown that the dissipation factor of OIP in contact with copper and brass increases, even in the absence of PD, but contact with aluminum and stainless steel has no influence on DFR of OIP. The results suggest that the influence of PD can be significant when estimating the moisture content or the level of thermal aging of OIP with DFR method.
Place, publisher, year, edition, pages
IEEE Press, 2016. Vol. 23, no 3, 1769-1777 p.
Partial discharge, dielectric frequency response, dielectric spectroscopy, transformers, oil-impregnated paper
Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-193844DOI: 10.1109/TDEI.2016.005169ISI: 000381510500065ScopusID: 2-s2.0-84982282666OAI: oai:DiVA.org:kth-193844DiVA: diva2:1034515
FunderSweGRIDS - Swedish Centre for Smart Grids and Energy Storage
QC 201610122016-10-122016-10-112016-10-12Bibliographically approved