Amprion Goes Offshore: Expansion and Conversion of the Hanekenfähr Substation

As part of the energy transition, the energy landscape in southern Emsland is undergoing a transformation. At the Hanekenfähr site, the Emsland nuclear power plant will be taken offline at the end of 2022. Simultaneously, increasing amounts of wind energy from the north must be efficiently integrated into the grid. Thus, at the Amprion Hanekenfähr substation, the offshore grid connection systems DolWin4 and BorWin4 will be connected to the transmission grid in 2028 and 2029. Amprion is addressing this change with extensive work at the Hanekenfähr substation. A key measure in this regard is the installation of two phase-shifting transformers, which enable better control and optimization of power flows. As part of a so-called site clearance, some overhead lines had to be dismantled and implemented as underground cables. For this purpose, egeplast Power Protect PE-RT protection pipes for high and extra-high voltage cables with a low-friction inner layer and individual marking were installed, partly trenchlessly, including the crossing of a railway line.

Lingen in Emsland is traditionally known as an important energy location in southern Emsland. Currently, the Emsland nuclear power plant with an output of 1.4 GW still feeds into the Amprion Hanekenfähr substation, which will be taken off the grid at the end of 2022. At the same time, the integration of wind energy at the Hanekenfähr site is becoming increasingly important. In 2028 and 2029, Amprion will commission the two offshore grid connection systems DolWin4 and BorWin4 there. Before that, the Hanekenfähr substation will be extensively expanded and converted. This includes the construction of two phase-shifting transformers and the expansion of the plant by several switchgear bays. For this purpose, a construction site clearance by cabling several overhead lines is necessary. This will be done as an underground cable system in two construction phases:

Section 1: New Construction of a 110 kV High-Voltage Three-Phase Connection as an Underground Cable

This connection consists of two 110 kV systems with three 110 kV underground cables each (connection of the “Rühle-Ost” and “Hanekenfähr-Holthausen” circuits) and leads from the Hanekenfähr substation to the cable support mast.

The first section was carried out as an undercrossing of the Münster-Norddeich railway line by means of pipe jacking DN 1,200 mm with a tunnel length of approximately 100 m. Subsequently, two cable protection pipe bundles including accompanying pipes were drawn into the jacking pipe. The second section of approximately 700 m was carried out using the open-cut method.

egeplast Power Protect PE-RT protection pipes for high and extra-high voltage cables with a low-friction inner layer and individual marking were used to ensure a correct connection to the respective voltage grid during the subsequent pulling-in of the underground cables, as explained by Civil Engineer (M.Sc.) Till Ruland from Heckmann Bau: “The high degree of precision required in confined spaces when pulling the pipe bundles into the DN 1,200 mm jacking pipe presents a major challenge here. A suitable system solution for cable protection pipes is indispensable.”

Section 1: New Construction of a 110 kV High-Voltage Three-Phase Connection as an Underground Cable

This connection consists of two 110 kV systems with three 110 kV underground cables each (connection of the “Rühle-Ost” and “Hanekenfähr-Holthausen” circuits) and leads from the Hanekenfähr substation to the cable support mast.

The first section was carried out as an undercrossing of the Münster-Norddeich railway line by means of pipe jacking DN 1,200 mm with a tunnel length of approximately 100 m. Subsequently, two cable protection pipe bundles including accompanying pipes were drawn into the jacking pipe. The second section of approximately 700 m was carried out using the open-cut method.

egeplast Power Protect PE-RT protection pipes for high and extra-high voltage cables with a low-friction inner layer and individual marking were used to ensure a correct connection to the respective voltage grid during the subsequent pulling-in of the underground cables, as explained by Civil Engineer (M.Sc.) Till Ruland from Heckmann Bau: “The high degree of precision required in confined spaces when pulling the pipe bundles into the DN 1,200 mm jacking pipe presents a major challenge here. A suitable system solution for cable protection pipes is indispensable.”