In East Frisia between Emden and Conneforde the existing 220 kV-high voltage line was replaced by a 380 kV line. Within a joint venture STREICHER was responsible for the construction of an empty conduit structure, that is used for pulling in underground cables at a later time.
Within the underground cable sections twelve parallel empty conduits with a diameter of 315 mm /200 mm & 75 mm for electricity cables, temperature monitors as well as two communication lines were laid. STREICHER carries out all horizontal wells with a total drillling length of 31.8 km. Three own horizontal drilling rigs with capacities of 50 or rather 80 t - amongst others also the new fully electric driven rig HDD80-E - were on duty to execute these wells with diameters of 550 mm, 450 mm or 300 mm. A special challenge was to guarantee the planned drilling process as accurately as possible (tolerance range of max. 0.5 m with vertical and horizontal sector). Moreover, the wells were not only carried out parallel but also like a fan from drilling start to the end.
The project was completed in summer 2021.
The line between Emden and Conneforde is one of the pilot projects, designed to provide information about the affect of underground cables on the electrical transmission system within the 380 kV three phases sector.