Auditoria

378
COPPER SULPHIDE IN TRANSFORMER INSULATION

Working Group A2.32

April 09

CIGRE WG A2.32

Copper sulphide in transformer insulation
MEMBERS: M. Dahlund, Sweden (convenor) I. Atanasova-Höhlein, Germany (leader TF 1) R. Maina, Italy (leader TF 2) N. Dominelli, Canada (leader TF 3) T. Ohnstad, Norway (leader TF 4) T. Amimoto, Japan C. Claiborne, USA M.-H. Ese, Norway J. Lukic, SerbiaV. Mezhvynskiy, Germany Ch. Perrier, France P. Smith, Germany J. Tanimura, Japan Y. Bertrand, France A. de Pablo, Spain P. Griffin, USA L. Lundgaard, Norway J. L. Nunes Jr., Brazil F. Scatiggio, Italy K. Sundkvist, Sweden J. Van Peteghem, Belgium

CORRESPONDING MEMBERS: X. Chendong, China Y. Vachiratarapadorn, Thailand

FORMER MEMBERS: V. Null, Germany V. Sokolov, Ukraine† Eric Sandré,France

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ISBN: 978-2-85873-065-0

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TABLE OF CONTENTS 1 2 2.1 2.2 2.3 2.4 3 3.1 3.2 3.3 4 4.1 4.2 4.3 4.4 4.5 55.1 5.2 5.3 5.4 6 6.1 6.2 7 INTRODUCTION ..................................................................................................................................... 3 THE PHENOMENON............................................................................................................................... 5 Copper sulphide formation.................................................................................................................. 8 Dielectric failure mechanism ............................................................................................................. 12 Influence of application and design ................................................................................................... 13 Influence of service conditions andoil maintenance......................................................................... 14 DIAGNOSTICS ...................................................................................................................................... 15 Oil testing...........................................................................................................................................15 Tests other than oil tests to detect deposits ...................................................................................... 18 Inspection .......................................................................................................................................... 18 MITIGATION TECHNIQUES................................................................................................................. 19 Metal passivators............................................................................................................................... 19 Removal of corrosive sulphur from oil in service............................................................................... 25 Oilexchange...................................................................................................................................... 25 Modified operating conditions............................................................................................................ 26 Removal of deposits .......................................................................................................................... 27 RECOMMENDATIONS...