Reducing SF6 emissions from electrical switchgear

Abstract

SF6 is a greenhouse gas applied in particular in electrical switchgear for the transmission and distribution of energy. It is indispensable for this purpose because of its superior electrical properties at high voltage. The consequent handling of SF6 and the continuous effort to reduce leakage from electrical switchgear by design and material has reduced and will further reduce emissions of SF6. Taking the German SF6 emission data reported annually, the authors tried to relate local emission data from several sources - not only electrical switchgear - with globally reported and measured SF6 concentrations. The latest revision of the European F-gas regulation, EU 517/2014, imposes the requirement on users to either perform regular leak search or install leakage detection systems on switchgear in service containing more than 6 kg of SF6. International switchgear standards pose limits on the leakage rate of equipment and prescribe routine tests before delivery. The paper presents several possibilities to reduce the SF6 emission from switchgear by design and choice of materials. Another source for emitted gas is the manual handling of SF6. As an example for improved SF6 handling, a "zero" emission automatic test and filling station for hermetically sealed switchgear is evaluated.