ASSESSING REAL ALTERNATIVES TO MV SF6 GAS-INSULATED SWITCHGEAR

The purpose of this paper is to analyse the different alternatives to SF6 filled metal-enclosed switchgear and controlgear in medium-voltage secondary distribution application, in order to improve the environmental footprint, having in mind that they are designed to keep the high-voltage parts insensible to different environments by enclosing them inside gas-filled sealed compartment(s). With this purpose, it is also very important to analyse and prioritise the criteria and attributes used to select the alternatives. Today, several gases and gas mixtures have been investigated and proposed as possible alternatives. Even, some of them are presented in commercial products as alternatives to SF6-filled ones. However, there's still short experience on their behaviour for their usual expected long life of more than 30 years, based on the service history of SF6-filled ones. Bearing in mind that these equipment are typically installed in electrical networks and without any maintenance in their inner high-voltage parts.