Estimating the remaining service life of asphalt-mica stator insulation

Author

Timperley, J.E. ; Michalec, J.R.

Author_Institution

American Electr. Power Service Corp., Columbus, OH, USA

Volume

9

Issue

4

fYear

1994

fDate

12/1/1994 12:00:00 AM

Firstpage

686

Lastpage

694

Abstract

Synchronous generators were manufactured with asphalt bonded, mica flake insulation from 1917 to the 1950s. There is a large fleet, perhaps two thousand, of these machines still in service today. This paper presents the results of a well documented series of field tests, many to failure, on 20 asphalt-mica insulated fossil fuel and hydroelectric synchronous generators on the American Electric Power system and laboratory tests on over 30 spare asphalt-mica stator bars and coils at AEP´s Dolan Laboratory. The paper clearly shows that a straightforward AC overpotential test and a simple graphical evaluation and analysis can be used to confidently determine the remaining service life of asphalt bonded, mica flake insulated synchronous generators that have been well maintained and operated within design limits

Keywords

electric breakdown; electric strength; insulation testing; life testing; machine insulation; machine testing; mica; stators; synchronous generators; AC overpotential test; asphalt-mica stator insulation; bars; coils; design limits; failure; field tests; fossil fuel generation; graphical evaluation; hydroelectric generation; laboratory tests; service life; synchronous generators; Asphalt; Bonding; Dielectrics and electrical insulation; Fossil fuels; Laboratories; Life estimation; Manufacturing; Stators; Synchronous generators; System testing;

fLanguage

English

Journal_Title

Energy Conversion, IEEE Transactions on

Publisher

ieee

ISSN

0885-8969

Type

jour

DOI

10.1109/60.368340

Filename

368340