Comparison and selection of accelerated corrosion test protocol for Gas Insulated Switchgear

Abstract

Gas insulated switchgear is performing key role for the distribution system operators (DSO’s). These types of equipment are mainly installed in industrial, urban, tropical and/or coastal regions and can be exposed to extreme environmental conditions, which are not yet covered by the current IEC TS 62271-304, dealing with the classification of the switchgear when they are expected to be operated in special service conditions, but not dealing with corrosion assessment. As an important part of the unit, a stainless-steel tank, which is welded and filled with pressurized gas such as SF6, persistently remains in contact with cyclic atmospheric and stressed conditions during its designed lifecycle which arises potential risk of stress corrosion cracking and pitting corrosion during use phase. This paper provides a detailed and comprehensive review of various existing standards, and best practices, of cyclic corrosion test (CCT), which depict about how to reproduce possible real-life conditions by testing, and helps to predict behavior of materials in different weather conditions. Comparison of these standards plays a vital role as there are many test standards and best practices are available. Therefore, for switchgear industries, it is extremely important to select CCT for stainless steel which is efficient, reliable and mitigate with a real-life condition. In this paper authors investigated various CCT and their applicability for pressurized tank, proposed a test protocols which can be used for accelerated test for product installed in special or extreme environmental conditions, to increase product robustness more and more required by climate change.