We swapped to vacuum breakers but I don't know if it will work for you. This is not a simple one to one replacement system. I would speak with the switchgear manufacturer and try and find examples of other product swaps already installed.
California outlawed the expansion of SF6 systems so they might be able to find one there or maybe in Europe. I don't know how Portugal's power grid is run but I would try to find a system that is similar to build off of.
