ASSESSING POSSIBLE ALTERNATIVES TO SF6 IN MV SWITCHGEAR

Abstract

SF6 gas is an essential part of a very well known and proven technology used in electricity transmission and distribution for insulation and current breaking purposes, allowing a reliable, safe and long life (30 to 50 years) network operation even in harsh environments. On the other hand, the release of SF6 gas to the atmosphere has a negative environmental impact on Global Warming despite having a small influence when a life cycle assessment is done on medium voltage switchgear, where manufacturing, use and disposal of the equipment is carried out in a responsible way. That means adopting the best technologies for monitoring and leakage testing, to monitor the ageing of the electrical network, and to recover the SF6 gas at the end of life for recycling or disposal. In parallel, ever since the GWP of SF6 was identified, R&D departments of major electrical equipment manufacturers have looked for a new technology that could replace SF6 whilst maintaining as much as possible the benefits that the SF6 Technology offers. This paper presents some tests assessing the behaviour and evolution of different gas mixtures during pilot experiences in an experimentation grid (UDEX). However, all individual efforts should be followed and/or accompanied by coordinated actions in order to standardize validation methods and subsequent appropriate revision of product standards.