Swissgrid seeks bids for modernisation of 220 kV substation in Switzerland February 5, 2020 | Europe News Switzerland’s transmission system operator (TSO), Swissgrid AG, has invited bids for modernisation of the 220 kV Saint-Triphon air-insulated switchgear (AIS) substation. This content is available to only paying subscribers. Username or E-mail Password Remember Me Forgot Password