On the frequency domain dielectric response of oil-paper insulation at low temperatures

authored by

Issouf Fofana, Hossein Hemmatjou, Fethi Meghnefi, Masoud Farzaneh, Alireza Setayeshmehr, Hossein Borsi, Ernst Gockenbach

Abstract

Results of Frequency Domain Spectroscopy measurements are known to be largely influenced by environmental conditions, such as the temperature. Because field measurements, last hours after de-energizing the transformer, the ambient temperature may affect the results. Especially in cold regions of the world, extreme care are required to interpret the results when performing tests at relatively low surrounding temperatures. A better understanding and analysis of the dielectric test results are therefore only possible with a clear understanding of the physical behavior of the insulation system in response to the ambient conditions. In this contribution, the dielectric behavior of a composite oil paper insulation system has been explained from the properties of Debye basic model. A series of experiments have been performed under controlled laboratory conditions with preset moisture content inside the insulation. The equivalent circuit parameters of a laboratory made oil paper condenser bushing model were obtained using a non-linear optimization procedure. Since the dielectric parameters values are geometry dependent, poles, calculated from resistances and capacitances, were used as they are independent of the geometry. It was shown that the poles can be regarded as parameters able to be used for insulation condition assessment.

Organisation(s)

High Voltage Engineering and Asset Management Section (Schering Institute)

External Organisation(s)

Universite du Quebec a Chicoutimi (UQAC)

Type

Article

Journal

IEEE Transactions on Dielectrics and Electrical Insulation

Volume

17

Pages

799-807

No. of pages

9

ISSN

1070-9878

Publication date

06.2010

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Electrical and Electronic Engineering

Electronic version(s)

https://doi.org/10.1109/TDEI.2010.5492253 (Access: Unknown)