Samstagern substation connection
At the Samstagern substation, modifications to the substation and line must be implemented in order to connect the line, which is currently operated at 150 kV, to the 220 kV grid.
Samstagern – Schweikrüti (Thalwil)
Between Samstagern and Schweikrüti (municipality of Thalwil), the line is already designed for extra-high voltage, but is only operated at 150 kV. Swissgrid is planning to increase the voltage to 220 kV. This will probably not require any major structural measures on the line.
Schweikrüti (Thalwil) – Kilchberg
A legally binding construction permit for a new overhead line along a modified route has been issued for this section. The construction of an underground cable is not possible on this section because two 132 kV SBB lines will be carried on the same pylons as the Swissgrid line. For technical reasons, the SBB lines must necessarily run above ground on this section. The Thalwil substation, which is important for supplying the western shore of Lake Zurich, will be connected to the Schweikrüti – Kilchberg section. As soon as the Thalwil substation is connected to the extra-high-voltage grid, Axpo’s 110 kV Obfelden – Thalwil line (known as the Albis line), which served as an alternative measure, will be dismantled. This will substantially reduce the burden on the residential areas of Langnau and Gattikon.
Kilchberg – Waldegg (Zurich)
The new line from Kilchberg to Frohalp near Zurich Manegg station will be built underground along the motorway. It will then be routed through the conduit blocks built during the construction of the two tunnel tubes of the Uetliberg tunnel before continuing to the Waldegg substation via a two-kilometre underground tunnel (with a diameter of approx. four metres).