When the Froloo substation near Therwil, Basel Land, was constructed in 1957 and 1958, all the power lines, insulators, air-break switches and transformers were located in the open air, protected by a high fence. Today, the situation is very different: over a period of four years, the outdoor facility was transformed into a state-of-the-art substation, equipped with cutting-edge technology. The new substation was designed and constructed by Alpiq EnerTrans AG on behalf of the two utility companies EBM and IWB, as well as Swissgrid.
The new substation houses all technical facilities in a single building. These include switchgear systems and transformers, but also various safety devices, earthing systems, fire alarm systems and control systems. Safety was given the highest priority in the overall design, with all electrical systems being protected against accidental contact and earthquake protection also having been taken into account.
The central role of “the region’s biggest plug socket”
The Froloo substation is “the region’s biggest plug socket”, functioning as one of the most important feed points for electrical energy in North-West Switzerland. The electricity at Froloo is obtained by Swissgrid from other, more distant power plants via two 220 kV power lines and transformed to lower voltage levels. The investment of around 40 million Swiss francs in this new substation will improve supply reliability throughout the region. The substation will be operated remotely by Swissgrid, AVAG and EBM network control units, making it possible to respond much more quickly to any faults that may occur.
Local residents will also benefit in other ways from the conversion of Froloo – with the large majority of the power lines disappearing from view and the rest of the outdoor facility due to be demolished by the end of 2015, an area of 7,000 square metres will now be restored to its natural state. Soon, visitors to this area will be able to enjoy the peaceful landscape without the sight of a technical facility from the last century.