Inter-array cable for floating platforms
Inter-array cable (IAC) assemblies, systems, and methods are disclosed in which a conductive cable between two floating platforms, e.g., floating wind turbine platforms, is suspended below the sea surface and above the seabed. One or more buoyancy sections are included in the cable, which reduces the static tension on the connection at the floating platform by reducing the suspended cable weight, and which provides geometric flexibility, allowing the IAC to comply with platform motions.
1. A cable assembly, comprising:
a cable having a plurality of cable sections, a first cable end, and a second cable end;
a first buoyant section joined to the cable at a first cable section;
a second buoyant section joined to the cable at a second cable section, and a third cable section extending between the first buoyant section and the second buoyant section; and
a terminal buoyant module connected to the first cable end, and a fourth cable section extending between the terminal buoyant module and the first buoyant section, wherein:
the first buoyant section and the second buoyant section are configured to provide buoyancy to the cable such that, when the cable is connected to a first floating platform and a second floating platform, the first buoyant section and the second buoyant section float submerged below a sea surface such that the first cable section and the second cable section are convex toward the sea surface and the cable does not contact the seabed; and
the terminal module is configured to provide buoyancy such that, when the first end of the cable is not connected to the first floating platform, the terminal module floats at the surface and the first and second buoyant sections are submerged and the cable does not contact the seabed.
2. The cable assembly of claim 1 , wherein:
the first floating platform includes a first floating wind turbine platform; and
the cable includes an insulated conductive cable dimensioned to conduct a power production of at least the first floating wind turbine platform.
3. The cable assembly of claim 1 , wherein:
the first buoyant section includes a first plurality of buoyant modules, each buoyant module connected to the cable and the first plurality of buoyant modules distributed along the first cable section.
4. The cable assembly of claim 1 further comprising: a first anchor connected to the cable within the third cable section.
5. The cable assembly of claim 1 , further comprising a second anchor connected to the cable at the second cable end or between the second buoyant section and the second cable end.
6. A cable assembly, comprising:
a cable having a plurality of cable sections, a first cable end and a second cable end;
a first buoyant section joined to the cable at a first cable section;
a second buoyant section joined to the cable at a second cable section, and a third cable section extending between the first buoyant section and the second buoyant section, wherein:
the first buoyant section and the second buoyant section are configured to provide buoyancy to the cable such that, when the cable is connected between a first floating platform and a second floating platform, the first buoyant section and the second buoyant section float submerged below a sea surface such that the first cable section and the second cable section are convex toward the sea surface and the cable does not contact the seabed; and
when the first cable end is not connected to the first floating platform, the first cable end hangs in the water column.
7. A system comprising:
a first floating platform;
a second floating platform; and
a cable assembly connectable between the first floating platform and the second floating platform, the cable assembly including:
a cable having a plurality of cable sections, a first cable end, and a second cable end;
a first buoyant section joined to the cable at a first cable section;
a second buoyant section joined to the cable at a second cable section, and a third cable section extending between the first buoyant section and the second buoyant section; and
a terminal buoyant module connected to the first cable end, and a fourth cable section extending between the terminal buoyant module and the first buoyant section, wherein:
the first buoyant section and the second buoyant section are configured to provide buoyancy to the cable such that, when the cable is connected between the first and second floating platforms, the first buoyant section and the second buoyant section float submerged below a sea surface such that the first cable section and the second cable section are convex toward the sea surface and the cable does not contact the seabed; and
the terminal module is configured to provide buoyancy such that, when the first cable end is not connected to the first floating platform, the terminal module floats at the surface and the first and second buoyant sections float submerged and the cable does not contact the seabed.
8. The system of claim 7 , wherein:
the first floating platform includes a first floating wind turbine platform;
the second floating platform includes a second floating wind turbine platform; and
the cable includes an insulated conductive cable dimensioned to conduct a power production of at least the first floating wind turbine platform.
9. The system of claim 7 , wherein:
the first buoyant section includes a first plurality of buoyant modules, each buoyant module connected to the cable and the first plurality of buoyant modules distributed along the first cable section.
10. The system of claim 7 further comprising: a first anchor connected to the cable within the third cable section.
11. The system of claim 10 , further comprising a second anchor connected to the cable at the second cable end or between the second buoyant section and the second cable end.
12. A method for providing an electrical connection between a first floating platform and a second floating platform, the method comprising:
providing a cable assembly connectable between the first floating platform and the second floating platform, the cable assembly including:
a cable having a plurality of cable sections, a first cable end, and a second cable end;
a first buoyant section joined to the cable at a first cable section;
a second buoyant section joined to the cable at a second cable section, and a third cable section extending between the first buoyant section and the second buoyant section; and
a terminal buoyant module connected to the first cable end, and a fourth cable section extending between the terminal buoyant module and the first buoyant section, wherein:
the first buoyant section and the second buoyant section are configured to provide buoyancy to the cable such that, when the cable is connected between the first and second floating platforms, the first buoyant section and the second buoyant section float submerged below a sea surface such that the first cable section and the second cable section are convex toward the sea surface and the cable does not contact the seabed; and
connecting the cable assembly to electrical connections of the first floating platform and the second floating platform.
13. The method of claim 12 , wherein:
the first buoyant section includes a first plurality of buoyant modules, each buoyant module connected to the cable and the first plurality of buoyant modules distributed along first cable section.
14. The method of claim 12 further comprising:
providing a first anchor connected to the cable within the third cable section;
and
disconnecting the first end of the cable from the first floating platform allowing the first terminal module to float at the surface.
15. The method of claim 14 further comprising:
providing a second anchor connected to the cable at the second cable end or between the second buoyant section and the second cable end;
providing a second terminal buoyant module connected to the second cable end, wherein:
the second terminal module is configured to provide buoyancy to the cable such that when the second cable end is not connected to the second floating platform, the second terminal module floats at the surface and the first and second buoyant sections float submerged and the cable does not contact the seabed; and
disconnecting the second cable end from the second floating platform allowing the second terminal module to float at the surface.