Paper recommendation: Research Article The dielectric behavior of outdoor high-voltage polymeric insulation due to environmental aging

Application of Dielectric Spectroscopy in HV insulation

ABSTRACT
Most of breakdowns are caused by aging effects of high-voltage insulation used within these components, and there is still a need of suitable tools to diagnose such systems non-destructively and reliably in the field. Several methods have been published in the last decade for which reliable diagnostics are claimed. One of these methods is based on changes of the dielectric properties of the insulation. Dielectric spectroscopy provides information on molecular dynamics and free charge carriers and it is sensitive to the insulation morphology, that is crystallinity, oxidation, additives, and impurities (ions and dipolar molecules). The measurement of dielectric constants and dielectric losses in frequency domain help to quantify the chemical and physical changes in the bulk of polymer due to aging. The results of frequency domain measurements in this contribution show that the effects of aging of insulators can be analyzed by this method. This paper demonstrates the use of a dielectric spectroscopy technique for monitoring the effect of different aging on silicone rubber, ethylene-propylene diene monomer (EPDM), and blend of silicone-EPDM and new polymeric alloy. New polymeric alloy is found to be suitable for humid environment and shows good hydro-thermal resistance compared to other polymers; also it is cheaper than other materials.

Copyright © 2006 John Wiley & Sons, Ltd.
The dielectric behavior of outdoor high-voltage polymeric insulation due to environmental aging
M. Ehsani 1 *, G. R. Bakhshandeh 1, J. Morshedian 1, H. Borsi 2, E. Gockenbach 2, A. A. Shayegani 3
1Department of Polymer Processing, Iran Polymer and Petrochemical Institute (IPPI), P.O. Box.14965/115, Tehran, Iran
2Institute of Electric Power Systems, Division of High Voltage Engineering, Schering Institute, University of Hannover, Callinstr. 25A, D-30167, Hannover, Germany
3High Voltage Laboratory, Electrical and Computer Engineering Department, University of Tehran, P.O. Box 14395-515, Tehran, Iran
*Correspondence to M. Ehsani, Department of Polymer Processing, Iran Polymer and Petrochemical Institute (IPPI), P.O. Box.14965/115, Tehran, Iran.
Funded by: Ministry of Energy of Iran

KEYWORDS
dissipation factor • permittivity • dielectric spectroscopy • polarization