Marine installation, comprising: a superstructure for power engineering; a foundation having: at least one connection structure arrangement having at least two connection structures, wherein each connection structure has: a horizontally encircling, vertically extending wall, which bounds a spatial region; a first connecting section, which is designed for connection to the superstructure; a second connecting section, which is designed for connection to the seabed anchoring means, wherein the first connecting section has a circumferentially completely encircling flange on the wall with through holes, through which screws for connection to the superstructure can be led, wherein at least one pump is provided within the spatial region in order to supply and/or to discharge seawater as a coolant to and/or from the superstructure; wherein the at least two connection structures are connected in such a way that the respective flanges of the first connection sections lie substantially in a horizontal plane, wherein the foundation furthermore has: at least one seabed anchoring means, wherein a number of the connection structures are equal to a number of the seabed anchoring means, wherein the seabed anchoring means is respectively connected to the connection structure by means of the second connecting section, and wherein the at least one connection structure is connected to the superstructure by means of the first connecting section, wherein the superstructure comprises: an HVDC substation, comprising an AC-DC converter module, in order to enable DC power transmission of AC power, in particular supplied by wind turbines, to a land station. a superstructure for power engineering; a foundation having: at least one connection structure arrangement having at least two connection structures, wherein each connection structure has: a horizontally encircling, vertically extending wall, which bounds a spatial region; a first connecting section, which is designed for connection to the superstructure; a second connecting section, which is designed for connection to the seabed anchoring means, wherein the first connecting section has a circumferentially completely encircling flange on the wall with through holes, through which screws for connection to the superstructure can be led, wherein at least one pump is provided within the spatial region in order to supply and/or to discharge seawater as a coolant to and/or from the superstructure; wherein the at least two connection structures are connected in such a way that the respective flanges of the first connection sections lie substantially in a horizontal plane, wherein the foundation furthermore has: at least one seabed anchoring means, wherein a number of the connection structures are equal to a number of the seabed anchoring means, wherein the seabed anchoring means is respectively connected to the connection structure by means of the second connecting section, and wherein the at least one connection structure is connected to the superstructure by means of the first connecting section, wherein the superstructure comprises: an HVDC substation, comprising an AC-DC converter module, in order to enable DC power transmission of AC power, in particular supplied by wind turbines, to a land station. a horizontally encircling, vertically extending wall, which bounds a spatial region; a first connecting section, which is designed for connection to the superstructure; a second connecting section, which is designed for connection to the seabed anchoring means, wherein the first connecting section has a circumferentially completely encircling flange on the wall with through holes, through which screws for connection to the superstructure can be led, wherein at least one pump is provided within the spatial region in order to supply and/or to discharge seawater as a coolant to and/or from the superstructure; wherein the at least two connection structures are connected in such a way that the respective flanges of the first connection sections lie substantially in a horizontal plane, wherein the foundation furthermore has: at least one seabed anchoring means, wherein a number of the connection structures are equal to a number of the seabed anchoring means, wherein the seabed anchoring means is respectively connected to the connection structure by means of the second connecting section, and wherein the at least one connection structure is connected to the superstructure by means of the first connecting section, at least one seabed anchoring means, wherein a number of the connection structures are equal to a number of the seabed anchoring means, wherein the seabed anchoring means is respectively connected to the connection structure by means of the second connecting section, and wherein the at least one connection structure is connected to the superstructure by means of the first connecting section, wherein the superstructure comprises: an HVDC substation, comprising an AC-DC converter module, in order to enable DC power transmission of AC power, in particular supplied by wind turbines, to a land station.