Stabilizing device, subsea system and use of stabilizing device

Abstract

A stabilization device (22) for a subsea cable unit (18) is disclosed, where the stabilization device (22) extends between a seabed (17) and a cable inlet (13) on a subsea structure (11), where the cable inlet (13) is located above the seabed (17). The subsea cable unit (18) comprises a subsea cable with a cable protection system (20) or only a subsea cable, and the stabilization device (22) comprises at least one stabilization base (24, 25) and at least one pile element (54) for anchoring the at least one stabilization base (24, 25) to the seabed (17) or the scour protection layer (15). The at least one pile element (54) is adapted to be driven into the seabed (17) or into the scour protection layer (15) such that the at least one stabilizing base (24, 25) is securely anchored to the seabed (17). The stabilizing device (22) further comprises a first clamping device (27) securely attached at one end to the at least one stabilizing base (24, 25), where the first clamping device (27) is curved and adapted to at least partially surround the subsea cable unit (18), and when the at least one stabilizing device (24, 25) and the subsea cable unit (18) are installed, the first clamping device (27) is configured to clamp the at least one stabilizing base (24, 25). A first clamping device (27) for holding the subsea cable unit (18); and a second clamping device (28) securely attached at one end to the at least one stabilizing base (24, 25), where the second clamping device (28) is curved and adapted to at least partially surround the subsea cable unit (18), and when the stabilizing device (22) and the subsea cable unit (18) are mounted, the second clamping device (28) holds the subsea cable unit (18).

Description

TECHNICAL FIELD

[0001] The present invention relates to a stabilizing device for stabilizing a cable in a subsea environment and a subsea system and a cable protection system. BACKGROUND

[0002] The fixed foundation offshore wind industry has developed a state-of-the-art approach around the cable, such as installation and protection of the cable. For many good reasons, cost being one of them, the industry has been seeking a static cable design to be used for the so-called inter-array grid. This is the cable that interconnects the individual wind turbine generators (WTG) with the transformer station (substation). In addition, the export cable from the offshore substation or the landfall cable to the onshore substation is based on a static cable design. These static cable designs can operate with very limited movements (i.e. dynamic). Apart from very limited movements during the operational power generation phase (typically between 20 and 40 years) and the decommissioning phase at the end of the offshore lease, such movements are typically mainly limited to the coiling or spooling during the manufacturing and installation phase.

[0003] The limited dynamic lifetime of the static cable design is defined by the cable design limitations, and for repeated movements (dynamics), a set of curvature and tension parameters define the fatigue lifetime of the cable design. The larger the dynamics (increased curvature and / or increased tension) the cable is subjected to, the shorter the fatigue lifetime of the cable.

[0004] It has proven that the installation and operation of the cable without protection of the cable will be difficult when handled during pull-in operations and in operations exposed to accelerated water particle velocity (current flow).

[0005] The industry state-of-the-art cable protection is to bury the cable in the seabed between the foundation devices. In addition to complying with existing regulations, the industry has developed several standards and recommended practices.

[0006] From early on, the wind turbine generators have used J-tubes as a standard configuration for the cable, but due to economics, a single pile (called J-less) design without J-tubes has been pursued, where the hole in the single pile wall is used for mechanical connection of the so-called cable protection system.

[0007] The intended main feature of the cable protection system that provides stability to the cables inside the cable protection system is in the trajectory between the single pile's hole without J-tube or any J-tube's trumpet and the seabed. However, stability can be a misconception. In fact, the cable protection system exposed to the accelerated water particles' velocity is not stable and moves everywhere. Various bending strain management or limitation solutions in the cable protection system reduce its mobility, but it is periodic, and thus the cables enclosed inside are forced to move with the cable protection system.

[0008] The cable protection system is forced to move with the surrounding water particles that are accelerated due to meteorological conditions (wind, waves, and current). Until 2020 and 2021, it was considered that Orcaflex and similar software and similar software were able to model the conditions and provide realistic scenarios regarding the magnitude and impact of water particles' flow velocity.

[0009] The cable protection system is modeled in software (Orcaflex or similar) as a model in which the trajectory of the cable protection system through the touchdown point until the seabed or scour protection in the single pile's hole or J-tube's trumpet is practically a chain, then continues over the scour protection / seabed to the burial point in the seabed. The forces mainly act on the chain because the water particles' velocity is highest when closest to the foundation device, and lower at the seabed burial point far from the foundation device. The worst case is produced in the most extreme sea conditions, which is represented as a limit state - the highest dynamic tension and the most severe bending of the cable protection system.

[0010] These dynamic forces are present in the form of tension in the seabed part of the cable protection system. To keep the cable protection system in place, an anchoring strength greater than the highest potential tension (from the calculated limit state) is required. This anchoring strength is called "hold-back capacity" and requires a part of the cable protection system to be buried in the seabed. The density or friction of the seabed and the characteristics of the seabed will determine how long this seabed length needs to be. The modeled hold-back capacity (assumed values used in the analysis) requires the seabed characteristics to be known and remain unchanged (i.e., the seabed characteristics are constant or better).

[0011] The procedure currently used mainly follows the trajectory that the cable protection system supplier must analyze (using Orcaflex or similar software) to demonstrate:

[0012] a) the cable design limitations (minimum bending radius and tension) are not affected, and

[0013] b) the cable fatigue life is higher than the project life cycle (usually a safety factor of 10, so a 32-year project requires a minimum of 320 years of cable fatigue life).

[0014] From 2019, an alarming number of failed cable protection systems and few failed cables were discovered. These can be categorized as environment-driven and engineering-driven.

[0015] In terms of environment, two important factors stand out.

[0016] 1) The acceleration of water particles around the vertical foundation device is more severe than predicted. This is also evidenced by scour protection, where D-90 stones (typically 275 kg in air) have been proposed in the last few years, whereas D-30 stones (typically 50 kg in air) were sufficient only 6-7 years ago.

[0017] 2) Another equally important environment-driven factor for the present invention is the seabed characteristics. The seabed characteristics in the upper two to three meters of the seabed were not typically known in the 2010s, whereas from 2017 to 2018, they were known through cone penetration testing (CPT) activities.

[0018] CPT is used as an important tool for cable burial risk assessment (CBRA), which mainly focuses on the burial depth below the existing / original seabed, providing foresight for the minimum reduction depth of the cable below the original seabed level.

[0019] Cone penetration testing is at best a misleading measure for assessing the impact of seabed characteristics on the buried part of the cable protection system. The reason is that the original seabed from which CPT data is obtained is disturbed during installation and burial activities. Therefore, the assessment leading to the analysis of the buried part of the cable protection system is based on a model in which the analysis has to assume and set parameters for the soil spring characteristics and the uplift resistance. There is no practical way to validate this even if the assumption values are not optimistically selected to allow the analysis to pass.

[0020] In addition to the seabed characteristics, the installation tolerances add further uncertainty to the burial point of the cable protection system relative to the foundation device. This amplifies the uncertainties, which are at best only defined assumptions (neither the seabed characteristics / soil spring-seabed interface is explicitly known, nor is the exact position of this soil spring at the time of installation).

[0021] In addition to these uncertainties, there are future unknown changes in the operational use of the cable protection system.

[0022] Until 2021, at least most analyses suggested that when the backfill on top of the cable protection system filled to the top of the trench, the backfill was similar to the original seabed (compacted solids) (but this assumption was at best set to a higher ballast weight than actual and did not match the actual degree of coverage of the cable protection system and / or the cable). Furthermore, by generally less than the assumed burial angle amplification, the anchoring strength of the cable protection system was assumed to be higher than conservatively considered and further away from the wind turbine generator or substation structure.

[0023] Both of these environmental conditions promote and amplify the mobility of the cable protection system over the scour protection and / or seabed, i.e. analyses that have been presented as “conservative models” provide unrealistic low mobility of the cable protection system. As a result, the behavior of the cable protection system is more dynamic, forcing the cable to higher curvatures and tensions (which shorten the cable fatigue life and can violate cable design limits). The increased curvature and tension in the cable protection system put more severe loads on the seabed interface soil springs and on the uplift resistance. As a result, the tension in the cable protection system overcomes the anchoring uplift resistance and pulls the buried portion of the cable protection system out of its buried location. This results in a longer portion of the cable protection system being exposed to dynamic and mobility, thereby transferring higher tensions to the cable in more severe curvatures.

[0024] Furthermore, a series of engineering deficiencies also played a role, one of which was the use of bend restrictors. According to the API-17 standards published by the American Petroleum Institute, i.e. (Flexible Pipe Ancillary Equipment Specification and Flexible Pipe Ancillary Equipment Recommended Practice), which sets recommended practices for flexible members, bend restrictors are strictly prohibited for non-static pipe sections (e.g. but not limited to the “static” portion of a catenary or lazy catenary loop flexible riser where dynamic isolation from the top is above the seabed float and the seabed is not influenced by surface weather).

[0025] The analysis assumed that the set of bend restrictors functioned in a uniform vertebrae manner. As a result, the analysis distributed all of the motion across the set, whereas in fact, small differences between each connection would cause the least frictional connection to act first and most significantly. Secondly, as the set of bend restrictors is pulled over the scour protection and / or seabed; the set of bend restrictors rolls. The repetitive motion reduces the initial friction (between connections) and the set of bend restrictors becomes a quasi-circular wheel-like structure that rolls over the scour protection and / or seabed with increasingly less friction.

[0026] This effect and the desire of designers and analysts for a “clean seawater environment” inside the cable protection system, hindered the understanding of the fact that in the turbid seawater near the seabed, the sand particles can create a very strong abrasive effect. In fact, rotating the bend limiter with a high abrasive sand mixture inside, not only wears the bend limiter itself, but also the cable from the inside of the cable protection system.

[0027] The discovery of these failures prompted the industry, in particular Orsted, to stabilize the cable protection system during 2021 and 2022, to prevent the cable protection system and cable from moving (Orsted stabilized a total of five wind farms, equipped with cable protection system designs based on bend limiters).

[0028] In this context, in 2022, the insurance industry serving the offshore wind industry, forced the “stabilization” of the cable protection system and cable before being able to issue new insurance policies.

[0029] Although the use of stones for stabilization solves the mobility of the cable protection system on the scour protection and / or seabed, it does change the condition of the cable protection system. The seabed trajectory is stabilized, but the chain section is still in a dynamic environment. Although the cable protection system under the stones is no longer moving, the characteristics and location of the soil spring model are still uncertain. The fixation of the cable protection system under stabilization increases the bending moment in the local fixation area. By fixation of the cable protection system and cable under the stabilization ballast, the local bending moment and tension in the fixation point or area are increased. This shortens the fatigue life of the cable and challenges the cable protection system with unaccounted bending moments.

[0030] Another aspect of stabilizing the cable or the cable protection system and cable is the cost of the stabilization material and installation. The cost of the stabilization material and installation varies, but it is estimated to be three to five times the cost of the cable protection system in the North Sea region of Europe. The cost is approximately three times more in the US region and approximately six times more in the Asia Pacific region.

[0031] In the already tight offshore logistics operation of building a wind farm, the stabilization has to be in place relatively shortly after the cable is pulled in. This increases the risk, complexity and cost of the installation process. Most developers will prioritize heavy lifting operations, and the stabilization process will extend the operating time, and the risk is that the cable protection system and cable are severely fatigued before they are stabilized. SUMMARY

[0032] It is therefore an object of the present invention to provide a stabilization of the cable protection system and / or cable, thereby eliminating the risk of seabed features or seabed changes.

[0033] It is also an object to provide stability of the cable and / or the cable protection system with a bend management system, thereby eliminating the risk of impaired cable fatigue life, i.e. the risk of cable failure during the operational life of the cable.

[0034] It is a further object to provide stability within the cable pull-in sequence.

[0035] It is a further object to stabilize the cable protection system and / or the cable without using ballast material, such as stones, stone bags, mats, etc.

[0036] It is a further object to provide stabilization of the cable protection system and / or the cable without using a crane and crane operation.

[0037] It is a further object to provide stabilization of the cable protection system and / or the cable without being close to a wind turbine, a generator or a substation.

[0038] It is a further object to provide a wide range of tolerances for positioning of the stabilization device for the cable protection system and / or the cable.

[0039] These objects are met by the stabilization device as defined in claim 1 and the subsea system as defined in claim 20 as well as the use of the stabilization device and the subsea system as defined in claim 25. Further embodiments of the present application are defined in the dependent claims.

[0040] Thus, there is provided a stabilization device for a subsea cable unit extending between a seabed and a cable inlet on a subsea structure, the cable inlet at the subsea structure being located above the seabed, wherein the subsea cable unit comprises a subsea cable with a cable protection system or comprises only a subsea cable, and wherein the stabilization device comprises:

[0041] - at least one stabilization base,

[0042] - a pile element for anchoring the at least one stabilization base to the seabed, the pile element being adapted to be driven into the seabed such that the at least one stabilization base can be securely anchored to the seabed,

[0043] - a first clamping device, one end of the first clamping device being securely attached to the at least one stabilization base, the first clamping device being curved and adapted to at least partially surround the subsea cable unit and hold the subsea cable unit when the stabilization device and the subsea cable unit are installed, and

[0044] - a second clamping device, one end of the second clamping device being securely attached to the stabilization base, the second clamping device being curved and adapted to at least partially surround the subsea cable unit and hold the subsea cable unit when the stabilization device and the subsea cable unit are installed.

[0045] The first and second clamping devices can be attached to the stabilizing base such that the first clamping device is closer to the subsea structure than the second clamping device, and wherein the first clamping device is flexible.

[0046] Preferably, the second clamping device is more rigid than the first clamping device.

[0047] Preferably, the at least one stabilizing base comprises at least one through hole, through which the pile element is adapted to pass.

[0048] Preferably, the stabilizing device comprises at least one bracket structure comprising at least one through hole for the pile element.

[0049] The pile element can be provided with an expansion device which exerts a force on the at least one stabilizing base towards the seabed.

[0050] Preferably, the expansion device is adapted to expand in case the seabed is eroded, thereby continuously exerting a force on the at least one stabilizing base towards the seabed.

[0051] For example, the expansion device can comprise a spring element.

[0052] Alternatively, the expansion device comprises a hydraulic element.

[0053] Alternatively, the expansion device further comprises a swelling element which swells in water.

[0054] The pile element can be provided with an adjustment device for adjusting the tension in the spring element, and thereby adjusting the force exerted on the at least one stabilizing base.

[0055] Preferably, the stabilizing device further comprises a sock unit for bend control of the subsea cable unit, wherein the sock is bent in the circumferential direction of the subsea cable unit and at least partly surrounds the subsea cable unit, and the sock unit and the subsea cable unit are held by the first and second clamping devices.

[0056] The sock unit can also be bent in the longitudinal direction of the subsea cable unit to prevent the cable from bending more than a desired angle. Alternatively, the sock unit can be generally straight and one end of the sock unit is more flexible, such that after installation the sock unit follows the chain shape of the subsea cable unit, thus the sock unit is bent in the longitudinal direction.

[0057] The sock unit can be provided with at least one movement preventing element on the side facing the subsea cable unit, wherein the at least one movement preventing element presses against the subsea cable unit.

[0058] The stabilizing device can comprise a first stabilizing base and a second stabilizing base, each comprising at least one through hole for a pile element adapted to be fitted in the at least one through hole and driven into the seabed, such that the first and second stabilizing base can be firmly anchored to the seabed.

[0059] Preferably, the first and second stabilizing base are arranged on opposite sides of the submarine cable unit.

[0060] Preferably, the first clamping device is firmly attached at one end to the first stabilizing base and at the other end to the second stabilizing base, and preferably the second clamping device is firmly attached at one end to the first stabilizing base and at the other end to the second stabilizing base.

[0061] The first clamping device can comprise at least one dynamic absorber, one end of which is anchored to the first and / or second stabilizing base and the other end of which is anchored to the cover unit.

[0062] The first and / or second stabilizing base is provided with a plurality of through holes for pile units adapted to be fitted in the respective through holes and driven into the seabed, such that the first and / or second stabilizing base can be firmly anchored to the seabed by means of the plurality of pile units.

[0063] Preferably, the at least one through hole is provided with a guiding element, thereby facilitating the entry of the pile element during installation.

[0064] The pile element can be adapted to be manipulated by an ROV.

[0065] The submarine cable unit can be provided with a cable protection device.

[0066] Preferably, the cable protection device surrounds the cable.

[0067] Preferably, the cable protection device extends at least over the stabilizing device. However, in some cases, the stabilizing device can not extend over the entire stabilizing device.

[0068] Preferably, the submarine structure is firmly installed in or to the seabed.

[0069] Also provided is a subsea system comprising a subsea structure firmly installed in or to a seabed and a subsea cable unit extending between the seabed and a cable inlet on the subsea structure, wherein the cable inlet at the subsea structure is located above the seabed, wherein the subsea cable unit comprises a subsea cable with a cable protection system or comprises only a subsea cable, and wherein the subsea system comprises a stabilizing device as defined above and does not comprise the additional features described above or comprises one, several or all of the additional features described above.

[0070] The subsea system can be provided with a plurality of stabilizing devices arranged along the longitudinal direction of the subsea cable unit.

[0071] The stabilizing device can be arranged on an erosion protection layer arranged on the seabed adjacent to the subsea structure.

[0072] Alternatively, the stabilizing device can be arranged directly on the seabed.

[0073] The subsea structure can be a monopile of a wind power plant firmly installed to or in the seabed. The subsea structure can also be other subsea structures firmly installed to the seabed. Alternatively, the subsea structure can be a semi-submersible structure, e.g. operating in a rather shallow depth, e.g. in a depth of up to 200-250 meters.

[0074] Also provided is the use of a stabilizing device as described above and / or a subsea system as described above for stabilizing a subsea power cable from an offshore wind power plant.

[0075] Thus, the stabilizing device according to the present application provides a foundation for the cable protection system and / or the stable anchoring of the cable to the seabed (fixed relative to the foundation means of the wind turbine generator or the substation, with or without an erosion protection) with a specific and permanent bending stress release, regardless of the current or future seabed characteristics or changes. The stabilizing device also provides a quantifiable bending strain release without the need to know or take the risk of the seabed characteristics or changes.

[0076] This allows the most advanced seabed positioning tolerances typical in the installation (for the foundation, the orifice height, the erosion protection and the cable and cable protection system) to be intercepted and captured in the bending management system and the stabilization.

[0077] Thus, the invention of the present application has at least the following advantages:

[0078] • The stabilization of the cable protection system is carried out in the erosion protection and / or the seabed.

[0079] • Bending stresses are managed by built-in bending stress relief.

[0080] • Stabilization into the seabed (through scour protection or mobile seabed).

[0081] • Bending stress relief and bending management are independent of seabed features (engineering bending management will remain, independent of seabed features), and are not affected by seabed changes (fluidity, scour, sand waves, seabed lowering, etc.).

[0082] • Stabilization is done without rock (or other ballast material).

[0083] • Stabilization is done while the cable is under tension.

[0084] • The stabilization device can be recycled (during operations for cable replacement or other reasons, and at end of life).

[0085] • Stabilization can be applied to existing (operational) cable protection systems, thus contributing to the operational features described above (stabilization with known bending management response).

[0086] • Stabilization is performed by a remote operated vehicle (ROV) with tool skid, without the need for close ship operations (very low risk of impact on foundations and cable / cable protection system).

[0087] • The weather window is not limited to platform access.

[0088] In addition, the stabilization device according to the invention also facilitates:

[0089] • The stabilization device allows dynamic forces to be isolated from the chain-like portion of the cable protection system (curvature and tension in the cable protection system are terminated at the stabilization device), so the cable protection requirements of the cable protection system from the stabilization device to the burial point are eliminated from most of the risks and fatigue issues.

[0090] • The invention reduces the dynamic forces experienced by the chain-like portion of the cable protection system.

[0091] • The curvature experienced by the cable protection system is less, and the stresses experienced are lower.

[0092] • The cable protection system is supported by a bending management system at ground touch (i.e. at the stabilization device).

[0093] • The tension from the chain-like portion of the cable protection system is controlled into the stabilization device, thus eliminating the tension of the cable protection system on the seabed.

[0094] • The curvature and tension strain on the cable is reduced.

[0095] • The cable fatigue life is increased.

[0096] • The stabilizing device allows for type qualification through the cable protection system (allows for various cable designs to meet cable fatigue life requirements with wider installation tolerances.

[0097] • The stabilizing device allows for the use of a flexible construction of the cable protection system, which can be made of polyurethane or any other suitable material than polyurethane.

[0098] • The stabilizing device allows for a cost-effective cable protection system design.

[0099] The stabilizing device can be used, for example, as a reliable seabed interface for a fixed offshore wind foundation, but the stabilizing device is not limited to this purpose. The stabilizing device can obviously be used with other types of equipment in other offshore industries with fixed foundations. The stabilizing device can also be used in other areas where the dynamics of the marine meteorological conditions can affect the flexible lines, such as cables, umbilicals, etc., in the seabed interface, and stabilization can be applied. This can be a floating structure or other suitable offshore structure.

[0100] Bending stress management / bending stress relief

[0101] The purpose of the invention is to provide a specific bending curvature for the cable and cable protection system regardless of the nature of the seabed or changes in the seabed, thus ensuring that the design limits of the cable and cable protection system are not breached and the cable fatigue life is extended above the required minimum.

[0102] The bending management system comprising the shroud unit will provide a bending stress relief feature (like a typical bend stiffener) for the cable and cable protection system even in cases where it covers at most 180 degrees of the cable or cable protection system circumference. In most cases, the frequent dynamics of sea water particles points to horizontal motion perpendicular to the direction of the cable and cable protection system.

[0103] Furthermore, the stabilizing device can provide a feature that encloses the tension and compression in the cable and cable protection system to scour protection or the seabed.

[0104] The stabilizing device can comprise a bending stiffening structure and alternatives, such as but not limited to a compression / elongation resisting device that performs two-dimensional bending management, such as a spring-like or hydro-pneumatic absorber type device.

[0105] Alternatively, the following combination: where the combined bending stiffness of the shroud unit can be provided by more than one feature, such as by the stiffness of the shroud unit and the stiffness of the struts or absorber cylinders.

[0106] At the side of the stabilizing base, or at the central part of the stabilizing base if the stabilizing unit is provided with multiple stabilizing bases, a curved stress management device, i.e. a cap unit, is positioned and shaped as a half cone to slide over the top of the cable protection system. This half-cone or dome-shaped structure is referred to as a cap.

[0107] This provides a bend management system that can be arranged on a submarine cable unit. The bend management system can be positioned close to the touchdown point at which the cable or cable protection system chain touches the seabed or scour protection without the need for an absolute positioning at the touchdown.

[0108] The cap unit has a tip end that can be lifted above the wing-like structure to maintain a smooth curvature of the cable protection system and cable chain.

[0109] The bending stiffness can gradually increase from the tip end. This provides a seabed docking for the cable and cable protection system, i.e. a bend stiffener towards the stabilizing position, that manages the bending stresses. This relieves the cable and cable protection system from the bending stresses managed by the stabilizing device.

[0110] The effect on the cable and cable protection system is that the curvature is limited to the bending moment allowed by the design of the stabilizing device. Removing severe curvatures reduces the overall mobility and reduces the local tension-slip-compression of the cable conductors. This reduces the wear of the cable and significantly increases the cable fatigue life.

[0111] While the cap is intended to be in contact with the 180 degrees upper circumference of the cable protection system and / or cable, if the cable protection system and / or cable chain drops below the cap arc, the tip end portion can have a reinforced vertical wall to provide Z-axis stability. This allows a wide berth of tolerance to the touch down of the cable and cable protection system when arranging the system on top of the cable protection system and cable.

[0112] At the back end, “away from the wind turbine generator”, the stiffness of the structure is preferably very high and can be solid, forming a gradually higher stiffness over the length of the cap.

[0113] The length of the bend stress management system provides a minimum limit of curvature above the cable fatigue life requirements (and greater than the design limits of the cable and cable protection system). The stiffness and length of the cap structure can be designed to provide a curvature low enough to ensure a minimum cable fatigue life.

[0114] The bending stiffness of the cap can preferably be supported by one or more absorber stags of the base, increasing the horizontal Z-axis stiffness and limiting the vertical (Y-axis) motion.

[0115] As mentioned above, the rear end of the cover can end in a solid (non-flexible) section. Preferably, this end section is kept fixed to one or more stabilizing bases.

[0116] Alternatively, the stabilizing base (in any shape) can be an enclosed structure with a flexible (elastic) front end docking section. The bend management arrangement is provided with the required stiffness (elasticity) to obtain the required limit of curvature, the ability to absorb bending moments from the elastic docking section, the cover structure or a combination.

[0117] Alternatively, the bend management system can be arranged to gradually limit the cable protection system and / or the cable free movement. This can be arranged in a semi-vertebrae horn shape or preferably this can be arranged in a series of poles according to the internal shape of the pole or according to the structural stiffness of the pole or according to a combination of the internal shape and structural stiffness of the pole. Preferably, the arrangement can be achieved by a single rigid pole or more rigid poles or similar arrangement to provide a zone for tension strain management.

[0118] Stable base

[0119] The purpose of the one or more stabilizing bases is to provide a docking between the bend and tension strain management system and the foundation into the seabed.

[0120] The purpose of the one or more stabilizing bases is also to provide a structure that is positioned above or embedded in the underlying material (erosion protection and / or seabed) when the structure is held towards the erosion protection and / or seabed.

[0121] The apparatus comprises at least one solid stabilizing base (open frame or block) that can be arranged on one side of the bend management system or, if there is more than one stabilizing base, on both sides.

[0122] The one or more stabilizing bases preferably have a vertical opening for at least one pile element in or at the side of the base.

[0123] The docking for at least one pile element of the one or more stabilizing bases can be arranged as a generally vertical hole or a reinforced opening inside or outside the base. Alternatively, a separate mechanical docking on the at least one pile can provide the transfer of stability of the foundation to the one or more stabilizing bases.

[0124] The one or more vertical holes or one or more attachment points can be spaced apart to allow initial penetration on both sides of a large armor stone on the erosion protection top layer.

[0125] One or more slots can exist on each stabilizing base to provide variable positions for driving in at least one pile. Alternatively, the fixation can use a clamp or cradle (not fixed to the stabilizing base) that is fitted to the pile foundation and prevents one or more stabilizing bases while anchoring into the seabed.

[0126] Alternatively, the stabilizing base (in any shape) can be an enclosed structure where the back end docking is fixed to a cap unit or the rigid part of the cap unit is incorporated into the base. One or more stabilizing bases can be single or double sided, located on each side of the bend management system, i.e. the cap unit.

[0127] One or more stabilizing bases can be designed with the full capacity of a single stabilizing base anchoring, but can provide the option of one or more stabilizing bases.

[0128] Preferably, one or more stabilizing bases can be equipped with a guiding device, for example, but not limited to, one or more pile element guides.

[0129] Tension strain management / friction or mechanical securing

[0130] The purpose of the friction feature is to stop the subsea cable unit in the longitudinal direction. The dynamic forces end at the friction part. This prevents the dynamic forces on the chain part of the trajectory that transmits the tension in further cabling from affecting the cable or cable protection system.

[0131] The cap unit can comprise a number of features to facilitate the following functions.

[0132] As mentioned above, towards the chain and bending into an upward arc with a convex tip, the cap unit can be provided with an initial low bending stiffness and towards the anchoring plate with an increased bending stiffness.

[0133] At the back end, away from the chain part of the cable protection system and / or the cable, the bending stiffness of the cap unit increases until the cap unit gradually becomes rigid. In this rigid "back end" of the cap, the cap stops the subsea cable unit.

[0134] In the rigid friction part of the cap unit, layers, pads can provide a grip on the cable or cable protection system. The force comes from at least one pile element and an expansion device, pushing the cap unit down onto the cable protection system surface.

[0135] Having the cover unit provided with a surface corresponding to the outer surface of the cable protection system and / or cable (e.g. but not limited to, providing an inner convex surface to follow the concave shape of the cable protection system and / or cable and / or protrusion to fit into a groove etc.) will provide a mechanical stop of the cable protection system inside the cover unit. This will provide a firm anchoring of the cable protection system and / or cable within the rigid part of the cover.

[0136] For operational stability means, i.e. the cable protection system and cable system are installed, the cover unit preferably has a part with a high friction pad that will be compressed onto the cable protection system surface during installation of the one or more stability bases. The use of a compression plate will allow for variations in the cable protection system, marine biofouling and sediment.

[0137] If the cable protection system or cable has a variable outer diameter, the cover unit can mirror this outer shape, preventing longitudinal movement of the cable protection system when tensioned.

[0138] For dedicated cable protection systems, position fixation can be provided by cams and sets of grooves.

[0139] The rigid part of the cover can have a friction pad or friction structure on the inside to provide enough friction over the top 180 degrees of the cable protection system to stop the cable protection system.

[0140] A dedicated cable protection system docking with a grooved part can interface with docking structures on the inside of the cover unit (e.g. cams protruding into any grooves will stop the cable protection system and prevent longitudinal movement of the cable protection system when tensioned).

[0141] Foundation

[0142] The purpose of the foundation is to provide a fixed horizontal position relative to the seabed structure, such as a wind turbine generator or a substation foundation, regardless of the mobility or changes in the surface seabed.

[0143] The preferred method of the foundation is to use at least one pile element or ground screw or similar. The at least one pile element can facilitate a ROV driven remote operated vehicle to carry the base / bend management system as well as the foundation (pile(s) / screw(s) etc.) in a tool sled. The tool sled can carry / dock one or more stability bases / cover units as well as the required pile elements / screws / anchors for one cable end.

[0144] Preferably, the operation is performed in a remote manner, i.e. flipping up and driving through (preferably vibratory piling, torque screwing, suction anchor piling).

[0145] The at least one pile element can be a typical pile (e.g. steel or concrete or any other material capable of being driven through the scour protection and / or seabed), a ground screw (a pile shaped structure that penetrates the seabed by rotation, or can be of the type of a suction pile anchor)

[0146] Preferably, each pile element, screw, etc. is capable of holding the stabilizing foundation fixed to the seabed until the end of the lifetime of the project. This includes but is not limited to absorbing installation impact, combined vertical and horizontal forces and compression.

[0147] During installation of the at least one pile element, hammering, vibration, screwing, suction or any combination can be used.

[0148] The at least one pile element can be a H-beam or X-beam, sheet pile, wooden pile, tubular, etc. (hammered or vibrated) in any shape or profile. For example, the at least one pile element can be a ground screw or a suction pile or a cone. The at least one pile can also be anchored in solid rock.

[0149] The at least one pile element can be equipped with an expansion device, for example an expandable (compressible) coupling. Compression can be achieved by the force when the at least one pile is driven into the seabed.

[0150] Preferably, the expansion device is compressed and fitted to the pile, etc. before installation. The arrangement that maintains the compression can be arranged to degrade or release within a short time after installation, thereby releasing the compression force onto the foundation.

[0151] Alternative foundation

[0152] An alternative foundation device for a submarine cable unit is also provided, which comprises a cable or a cable provided with a cable protection system to mitigate a lowering of the seabed without changing the chain shape of the installed submarine cable unit. Such lowering of the seabed can be due to seabed erosion or scouring locally below the submarine cable unit or seabed erosion or scouring in all areas around the submarine cable unit.

[0153] The alternative foundation device is therefore advantageous in enabling installation of a submarine cable unit in a position in which erosion creates a free span of the submarine cable unit between the touch down point of the built submarine cable unit and the original seabed level or scouring layer level before erosion. The alternative foundation device thus enables installation of a submarine cable unit suspended above the seabed level, providing an artificial touch down foundation for the cable and CPS elevated above the seabed level, without changing the chain shape and thus also the tension in the cable.

[0154] The foundation device can also be used in situations where erosion is expected to occur due to local water flow conditions, or in situations where laying a submarine cable unit on a depression in the seabed would result in excessive bending of the submarine cable unit.

[0155] Therefore, a foundation device for a submarine cable unit is provided, the submarine cable unit comprising a submarine cable provided with a cable protection system or only comprising a submarine cable, the foundation device comprising:

[0156] - a pile element adapted to be driven into the seabed or scour protection layer,

[0157] - an attachment unit mounted to an upper part of the pile element,

[0158] - a support element attached to the attachment unit and adapted to support the submarine cable unit when the foundation device is installed.

[0159] - a locking element attached to the attachment unit and adapted to lock the submarine cable unit at least to the foundation unit.

[0160] Preferably, a bend stiffener unit is also provided, comprising a bend stiffener body adapted to be arranged on the submarine cable unit to control the bending of the submarine cable unit, the bend stiffener unit further comprising at least one attachment element attached to the bend stiffener body and extending outwardly from an outer surface of the bend stiffener body, wherein the attachment element is adapted to be positioned between the support element and the locking element.

[0161] The bend stiffener unit is preferably provided with at least two attachment elements arranged on one side of the bend stiffener body and spaced apart in the longitudinal direction of the bend stiffener body. Preferably, the distance between the two attachment elements is adapted to the dimensions of the locking element, i.e. to the conical shape of the locking element.

[0162] The support element and / or the locking element are preferably mounted on the attachment unit in an adjustable manner.

[0163] The attachment unit can be threaded and the support element and / or the locking element can be threaded in a corresponding manner, such that the position of the support element and / or the locking element on the attachment unit is adjustable.

[0164] The support element can be provided with a conical support element contact surface on which the submarine cable unit rests. The conical shape of the support element is preferably adapted to provide the submarine cable unit with the best possible support, taking into account the inclined position of the pile element relative to the seabed or scour protection layer after installation.

[0165] The bending stiffener body of the bending stiffener unit preferably has a semi-circular top shape. This means that, when the bending stiffener unit is arranged on the submarine cable unit, the bending stiffener body covers approximately the upper half of the outer surface of the submarine cable unit.

[0166] The bending stiffener unit is preferably provided with attachment elements that are wedge-shaped, having respective attachment element contact surfaces adapted to abut against the locking element.

[0167] The locking element is preferably provided with a locking element locking surface that faces the conically shaped one or more attachment elements of the bending stiffener unit.

[0168] Preferably, the locking element locking surface abuts against the attachment element contact surfaces of the attachment elements of the bending stiffener unit after installation of the foundation device.

[0169] The bending stiffener unit is also preferably provided with four attachment elements, wherein two attachment elements are arranged on either side of the bending stiffener body and are spaced apart in the longitudinal direction of the bending stiffener body.

[0170] Preferably, the distance between the two pairs of attachment elements located on either side of the bending stiffener body is adapted to the dimensions of the locking element, i.e. to the conical shape of the locking element arranged or installed on the attachment unit with the two pile elements.

[0171] A method is also provided for providing a foundation for a submarine cable unit, wherein the submarine cable unit comprises a submarine cable provided with a cable protection system or only comprises a submarine cable, the method comprising the following steps:

[0172] - providing two foundation devices according to any one of the above-mentioned embodiments,

[0173] - partially arranging the pile element of the foundation device in the seabed and / or scour protection layer, such that the pile element of the foundation device is inclined with respect to the seabed or scour protection layer and such that the support element arranged on the attachment unit is in a position to support the submarine cable unit,

[0174] - if the submarine cable unit has not yet been installed, installing the submarine cable unit such that the submarine cable unit is supported by the support element of the foundation device,

[0175] - arranging the locking element on the attachment unit of its respective pile element, such that the submarine cable unit is locked in its position on the support element.

[0176] The method further comprises arranging the bend stiffener unit on the submarine cable unit such that the attachment elements are adjacent to the attachment units of the pile elements, and then arranging the locking elements on the attachment units.

[0177] Preferably, the locking elements are arranged on the attachment units of their respective pile elements such that the locking elements abut the attachment elements of the bend stiffener unit and lock the bend stiffener unit and the submarine cable unit in place.

[0178] Preferably, the two pile elements are arranged such that the support elements support the submarine cable unit after installation. The position of the support elements on the attachment can be adjusted to a desired position to enable the support elements to support the submarine cable unit.

[0179] After the two pile elements are arranged in their desired position and the support elements support the submarine cable, the bend stiffener body is preferably arranged on top of the submarine cable unit such that the attachment elements of the bend stiffener unit are adjacent to the attachment units on the pile elements.

[0180] The pile elements are arranged such that the pile elements are inclined with respect to the seabed or scour protection layer. Thereby, the pile elements have a scissor-like form. The arrangement of the two foundation devices will provide a stable support for the submarine cable unit.

[0181] Compression onto seabed

[0182] The purpose of this feature is to maintain vertical contact of the foundation and the bend management system with the seabed in case of a horizontal drop of the scour protection or seabed.

[0183] The stabilizing device needs to be compressed onto the underlying seabed or scour protection to ensure that the cable protection system is fixed within the cover. To provide support in case of a potential scour protection subsidence or seabed subsidence and scour, the vertical foundation of the one or more foundations is coupled to the at least one pile element, rod, column, etc. via a pre-tensioned expansion device. This expansion device forces the one or more stabilizing foundations downwardly against the seabed or scour protection, thereby ensuring that the one or more stabilizing foundations remain at seabed level or scour protection level after a final drop in the level of the seabed or scour protection. The expansion device can comprise a compression spring device, such as a spring element, or any other device capable of elongating in length and simultaneously pressing the one or more stabilizing foundations downwardly against the seabed or scour protection. The elongated length is preferably designed to at least reach the maximum drop that can occur in the level of the seabed or scour protection.

[0184] The expansion device can be pre-tensioned and compacted by means of degradable clamps, ropes or the like and released after a predetermined time after installation

[0185] Space reserved for foundation lowering (sinking into the seabed) of a wind turbine generator

[0186] The purpose of this feature is to ensure that the cable protection system and the cable curvature are not compressed in the event of the foundation of the wind turbine generator sinking to the seabed after the cable has been installed.

[0187] By pre-setting the curvature of the cable protection system and positioning the base on the chain inside the cable protection system touchdown point, it is possible to absorb the reduction in bore height while maintaining a large bend radius, while ensuring that the cable protection system and the cable routing distance inside the MP foundation are not shortened. This will prevent the internal cable structure from being compressed (which will increase cable fatigue).

[0188] Mounting feature

[0189] The purpose of these features is to minimize the impact on the critical path of offshore construction activities, reduce risks, and at the same time provide stability for the installed cable and cable protection system.

[0190] The stabilizing device is designed to be placed on top of the cable or cable protection system, so that the cable or cable protection system laid above the underlying seabed will be covered by the structure. The versatility of the subsea seabed anchoring allows one to choose to use a single pile element or more pile elements to make one or more stabilizing bases as the basis for stabilization.

[0191] Both the stabilizing device and the one or more pile elements can be transported by a remotely operated vehicle (ROV), the tool skid of which can dock the stabilizing device and the one or more pile elements before the ROV is launched. After reaching the underwater location, the stabilizing device is released and placed on top of the cable protection system, for example, using a robotic arm, and then the tool skid inverts at least one pile element (etc.), and when its bottom end is located in the docking portion of the stabilizing base, it is driven into the pile by the power unit of the ROV, for example, a hydraulic power device for hydraulic driving of the ROV or an electric power group.

[0192] This installation does not require heavy lifting or bringing surface vessels close to the seabed structure.

[0193] Furthermore, the stabilisation operation can be performed simultaneously with the cable pull and incorporated into the pull procedure without impacting the critical path. For example, the stabilisation operation can be performed during the time period between the cable protection system being locked to the bore or trumpet and the temporary cable hang being established. Typically, a period of 30 to 60 minutes is sufficient for the ROV to monitor the subsea termination, so utilising this period for the foundation installation does not impact the cable installation efficiency. This means that the stabilisation of the cable protection system and / or cable can be performed during the cable pull and can be achieved by utilising the idle observation station ROV during the usual 30 to 60 minute wait time between the cable protection system latching / interlocking and the temporary hang of the cable in the tower. In this way, the stabilisation device is taken out of the critical path of the cable installation and so does not delay the cable installation and provides stabilisation immediately upon the pull.

[0194] The installation does not impact the cable within the cable protection system, for example, the stabilisation can be performed after the cable protection system is locked, thereby allowing the cable to be pulled to the switchgear after stabilisation.

[0195] The installation can also be performed from a CLV (cable layer vessel) operated by an ROV.

[0196] Material

[0197] Cost is a key barrier to the development of offshore wind power. The present invention allows the use of "low grade" industrial available materials, such as glass fibre reinforced epoxy, carbon steel etc. and can provide steel with an anode and allow for water absorption to meet design criteria - including end of useful life - to be designed. Thus, the use of special materials, such as high cost steels, composites or polymers can be avoided.

[0198] The use of generic industrial materials, not dedicated to the cable protection or other niche markets, not only ensures low cost materials, but also allows for industrial production in most regions, thereby avoiding transportation costs and carbon dioxide emissions and creating local supply chain opportunities in the wind farm installation area.

[0199] Type identification

[0200] The present invention provides an optional type qualification for various cable designs (within a large tolerance range of the base interface height, chain length and position of the present invention). This type qualification is possible because the stabilisation with a specified bending response removes the task of the cable protection system to deal with the curvature and stresses when the chain hits the ground. This enables the present invention to be designed with the ability to cope with the worst case scenario, thereby reducing the bending moments and tensions imposed on and managed by the cable protection system. The design of this ability can ensure that even the most demanding cable design meets the requirements for cable fatigue life.

[0201] This ensures that the cable boundary conditions considered during the cable design phase can be optimised. There is no need to consider extreme curvature and tension parameters for the cable design, allowing optimisation of the cable design parameters for the primary function of the cable (power and signal transmission) and associated costs.

[0202] The stabilisation device has the following advantages in terms of installation:

[0203] • No need to work close to the host vessel.

[0204] • No need to lift heavy ballast material.

[0205] • Immediate stabilisation (during embedment of the cable installation).

[0206] • Quick operation (15-25 minutes).

[0207] • This can be done on the seabed or through scour protection.

[0208] Any auxiliary vessel with ROV capability can install the stabilisation device into an operable cable protection system and cable system, which means:

[0209] 1. No need to work close to the host vessel.

[0210] 2. No need to lift heavy ballast material.

[0211] 3. No need for personnel to enter the tower.

[0212] 4. Quick operation (15-25 minutes).

[0213] The present invention therefore has a number of advantages:

[0214] • The present invention provides stabilisation of the cable protection system and / or cable, thereby eliminating the risk of seabed features or seabed changes.

[0215] o The cable protection system and / or cable is stabilised, thereby eliminating the effects of seabed features, risks and uncertainties - including but not limited to seabed mobility and variability.

[0216] • The present invention provides stabilisation through a bend management system, thereby eliminating the risk of affecting the fatigue life of the cable (eliminating the risk of the cable failing during its service life).

[0217] o A bend management system is provided which can reduce the severe bending of the cable protection system and / or cable, reducing the effects of localised tension-slip-compression on the cable, thereby extending the fatigue life of the cable.

[0218] • The present invention provides stabilisation during the installation of the cable.

[0219] o The stabilizing device allows for immediate stabilization during the cable installation process without impacting the critical path.

[0220] • The present invention provides stabilization without the use of ballast material (rock, rock sock, mats, etc.).

[0221] o The stabilizing device works without the need for ballast material.

[0222] • The present invention provides stabilization without the need for crane / lifting operations.

[0223] o No lifting or crane operations are required.

[0224] • The present invention provides stabilization without the need for access to the wind turbine generator or substation.

[0225] o The surface vessel does not need to access the offshore foundation for operations.

[0226] • The present invention provides a greater tolerance range for positioning.

[0227] o No need for tedious and often difficult to achieve positioning accuracy.

[0228] • The present invention captures the fall of the MP foundation after installation.

[0229] o No need for cable protection systems and / or cable compression, thus avoiding the sinking (lowering) of the monopile of the wind turbine generator.

[0230] In short, the system provides a solution for addressing cable protection system and / or cable fatigue life threatening conditions, eliminating the uncertainty of the seabed interface, and without the need for ballast material, thus providing a stable bend management system that absorbs seabed variations and installation variations.

[0231] Not only is there no need for ballast material, transportation, and installation, but also the risk and uncertainty of using ballast material to stabilize the cable and / or cable protection system is eliminated. BRIEF DESCRIPTION OF DRAWINGS

[0232] Non-limiting embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0233] Figure 1 The stabilizing device and subsea system are shown from the side.

[0234] Figure 2 The stabilizing device and subsea system are shown in perspective view.

[0235] Figure 3 The stabilizing device is shown.

[0236] Figure 4 A stabilizing device with a pile element and an expansion device of the pile element is shown.

[0237] Figure 5 A stabilizing device and a pile element driven into the seabed and / or into a scour protection layer are shown.

[0238] Figure 6 A cover unit of a stabilizing device with a first clamping device and a second clamping device is shown.

[0239] Figure 7 A stabilizing device without a pile element is shown.

[0240] Figure 8 A stabilizing device is shown from the front. Figure 7 A stabilizing device is shown.

[0241] Figure 9 A stabilizing device is shown which comprises two stabilizing bases, namely a first stabilizing base and a second stabilizing base arranged on both sides of the cover unit.

[0242] Figure 10 A stabilizing device is shown which comprises separate and unfastened clamping elements comprising at least one hole for a pile element.

[0243] Figure 11 A stabilizing device is shown from below with separate and unfastened clamping elements as shown in Figure 10 A stabilizing device is shown.

[0244] Figure 12 A stabilizing device is shown which comprises separate and unfastened clamping elements of different design, which also comprise at least one hole for a pile element.

[0245] Figure 13 A stabilizing device is shown which comprises a dynamic shock absorber.

[0246] Figure 14 A stabilizing device is shown which comprises two dynamic shock absorbers, which are attached to the cover unit, respectively, and to the first stabilizing base and the second stabilizing base.

[0247] Figure 15 A cover unit is shown which is provided with a movement prevention element which is adapted to engage with a submarine cable passing through the cover unit of the stabilizing unit or with a cable protection system in the case where a cable protection system is provided for the submarine cable.

[0248] Figure 16 A cover unit is shown from a slightly different angle which is provided with a movement prevention element as shown in Figure 15 A cover unit is shown.

[0249] Figure 17 A cover unit is shown provided with a movement preventing element in the form of a groove / cavity / recess / notch adapted to engage with the cable protection system and / or the part of the cable passing through the cover unit.

[0250] Figure 18 A stabilizing device is shown centrally positioned on top of the ground contact point of the cable protection system and / or the cable.

[0251] Figure 19 A stabilizing device is shown positioned outside the ground contact point of the cable protection system and / or the cable system.

[0252] Figure 20 Two positions of the central part of a stabilizing device are shown, one stabilizing device positioned outside the ground contact point of the cable protection system and / or the cable system on the left side of the figure, and the other stabilizing device positioned inside the ground contact point of the cable protection system and / or the cable system on the right side of the figure.

[0253] Figure 21 A stabilizing device is shown arranged on the scour protection.

[0254] Figure 22 A stabilizing base is shown, wherein the hole for the pile element is provided with a corresponding guiding element.

[0255] Figure 23 An expansion device of a stabilizing device is shown, in the middle part of the figure in a compressed state, and on the right side of the figure in a relaxed state.

[0256] Figure 24 A stabilizing device is shown mounted on a scouring seabed.

[0257] Figure 25 A stabilizing device is shown in two positions in case of a lowering of the seabed level, in the upper part of the figure the installation height corresponding to the seabed level at installation is shown, and in the lower part of the figure the installation height after lowering of the seabed level is shown.

[0258] Figure 26 A stabilizing device is shown at installation before lowering of the seabed level.

[0259] Figure 27 A stabilizing device is shown after lowering of the seabed level.

[0260] Figure 28 A bend management system is shown, which can be used as Figures 1 to 26 An alternative to the cover unit shown.

[0261] Figure 29 A cover unit is shown from the side.Figure 28 The shown bend management system.

[0262] Figure 30 A stabilizing system with a plurality of clamping devices is shown, which form a half-horn, i.e. the length of the clamping devices is gradually increasing from one end to the other end.

[0263] Figure 31 A view from above is shown Figure 30 The shown stabilizing system with a plurality of clamping devices.

[0264] Figure 32 A blocking device is shown, which deforms the outer surface of the cable protection system in a defined manner in order to intensify the longitudinal blocking effect.

[0265] Figure 33 A view from below is shown Figure 32 The shown stabilizing device.

[0266] Figure 34 A submarine cable is shown, which is provided with a cable protection system, which is arranged on the seabed or on an erosion protection layer on the seabed.

[0267] Figure 35 A view from above is shown Figure 34 The shown cable with a cable protection system, wherein the seabed or the erosion protection layer has dropped by a distance D due to erosion or the like, so that the cable and the cable protection system are suspended above the seabed or the erosion protection layer.

[0268] Figure 36 A submarine cable unit and two foundation devices are shown, which are arranged in the seabed and / or the erosion protection layer and are inclined with respect to the seabed or the erosion protection layer and form a scissors shape and support the submarine cable unit suspended above the seabed or the erosion protection layer.

[0269] Figure 37 A submarine cable unit is shown, which is supported by two support elements, which are arranged on the two pile elements of the foundation devices, and a bend stiffener unit is lowered onto the top of the submarine cable unit.

[0270] Figure 38 The same procedure is shown in a side view, i.e. the lowering of the bend stiffener unit onto the top of the submarine cable unit. Figure 37

[0271] Figure 39 A submarine cable unit is shown, wherein a bend stiffener unit is mounted on the top of the submarine cable unit and locks the submarine cable and the bend stiffener unit in place by means of a locking element arranged on the pile element. ​

[0272] Figure 40a and Figure 40b Showing the front view and side view respectively. Figure 39 The same content. First, it should be noted that the submarine cable unit 18 of the present invention can be a separate cable or a cable equipped with a cable protection system 20. Detailed Implementation

[0273] Figure 1 and Figure 2 A stabilization device 22 and a subsea system 10 according to the invention are shown, wherein the subsea system includes a monopile 12. A particular application of the stabilization device 22 according to the invention is in the offshore wind power industry, where a known cable protection system 20 is used for a monopile foundation 12 without a J-tube assembly—referred to as "J-less". Here is a cable inlet or opening 13 on the monopile foundation 12, wherein the cable protection system 20 of the subsea cable unit 18 is mechanically locked in the opening 13 via a mechanical connector / latch / dating unit 14 of the cable protection system 20.

[0274] The stabilizing device 22 is inserted into the seabed 17 via one or more pile elements 54, which penetrate the upper layer, the top layer affected by movement, and the possible scour protection layer 15.

[0275] Although the stabilizing device 22 shown in the figure is a submarine cable unit for a monopile foundation 12, it is also applicable to other types of foundations and joints. For example, including but not limited to J-tube flared joints for wind turbine generators, and can be applied to other submarine joints in which underwater lines (cables, flexible cables, umbilical cables, etc.) will benefit from a controlled bend management system.

[0276] Figure 3 The stabilizing device 22 according to the invention is shown in more detail. Preferably, the stabilizing device 22 is designed to be mounted on top of the submarine cable unit 18, thereby placing it on top of the cable protection system 20. Preferably, the stabilizing device 22 is fixed to its position relative to the wind turbine generator or substation foundation by means of a pile element 54, wherein the pile element 54 has a processing docking portion 57 on its top portion 56 (see...). Figure 23), which processing interface 57 is used for processing and inversion, for example via an ROV. The one or more pile elements 54 provide horizontal stability to the stabilizing device 22. The pile elements 54 also provide vertical stability to the stabilizing device 22 relative to the seabed 17 and / or the scour protection layer 15. Preferably, the top portion 56 of the pile elements 54 of the stabilizing device 22 can be equipped with expansion devices 59 with expansion capacity. This provides a vertical force to the at least one stabilizing base 24, 25 provided by the stabilizing device 22, ensuring that the stabilizing device 22 remains compressed towards the seabed 17, even in the event of a decrease in the level of the seabed 17 due to, for example, erosion.

[0277] The stabilizing device 22 provides a bending stress release function to the submarine cable unit 18, which is preferably arranged as a dome-shaped structure of a cover unit 45. The cover unit 45 covers 180 degrees, preferably more than 180 degrees, of the upper circumferential portion of the submarine cable unit 18. To cooperate with the bend management system, the cover unit 45 can be assisted with a flexible interface towards the submarine cable unit 18 and / or the cable chain, preferably in the form of a first clamping device 27, which is attached to the at least one stabilizing base 24, 25, and a more rigid interface towards the other end of the at least one stabilizing base 24, 25, i.e. the end away from the submarine cable unit chain, preferably in the form of a second clamping device 28, which has a greater bending moment than the first clamping device 27.

[0278] As shown in Figure 4 , the stabilizing device 22 can be arranged on top of the submarine cable unit 18, i.e. the cable protection system 20 and / or the cable, with at least one stabilizing base 24, 25 of the stabilizing device 22 arranged on one side of the submarine cable unit 18, or as shown in Figure 4 , on both sides of the submarine cable unit 18. The double-sided stabilizing base 24, 25, i.e. comprising a first stabilizing base 24 and a second stabilizing base 25, arranged on both sides of the submarine cable unit 18 through the stabilizing device 22, can be adapted to improve the stability on uneven surfaces, such as, but not limited to, large armor layer rocks, such as, but not limited to, D90 rocks (900 mm in diameter). Both the first stabilizing base 24 and the second stabilizing base 25 are provided with at least one attachment device, such as a through hole 42, for attaching a pile element 54. Figure 4In the middle, the first and second stabilizing base 24, 25 are each provided with three through holes 42, through which the pile elements 54 can pass. In the present example, each of the first and second stabilizing base 24, 25 is stabilized by a single pile element 54, but a pile element 54 can also be provided in each through hole 42. The top portion 56 of the pile element 54 has a sufficient length so as to provide, as shown, an expansion device 59 which can be compressed during driving of the pile element 54, or, preferably, as shown, the expansion device 59 is compressed beforehand to a set compression length before the stabilizing device 22 is installed.

[0279] As Figure 5 shown, the stabilizing device 22 can be positioned onto the seabed without the scour protection layer 15, the pile elements 54 will penetrate into the seabed 17. The penetration length portion 55 of the pile elements 54 will maintain, together with the expansion device 59, a horizontal position relative to the monopile 12 of the wind turbine generator or substation foundation, thereby maintaining the vertical position of the at least one stabilizing base 24, 25 and thus of the cap unit 45 and the first and second clamping devices 27, 28 clamped onto the submarine cable unit 18.

[0280] As Figure 6 shown, the cap unit 45 of the bend management system can be provided in a dome shape in the longitudinal direction of the cap unit 45, preferably the cap unit 45 has a flexible tip portion 46 which allows the dome shape of the cap unit 45 to follow the trajectory of the chain of the submarine cable unit 18. With a relatively soft tip portion, so that when the dome central portion 47 of the cap unit 45 and the horizontal portion 48 of the cap unit 45 are pressed down around the submarine cable unit 18, the tip portion 46 of the cap unit 45 with the lower stiffness will a) follow the chain shape of the submarine cable unit 18, b) ensure a tapered bend stress relief with the lowest forced at the start of the dome portion. The side portions 49 of the dome portion can be lowered to allow guiding of the submarine cable unit 18 even without compression of the submarine cable unit towards the inner roof of the dome portion of the cap unit.

[0281] The stiffness of the cap unit 45 of the bend management system is similar to a conventional bend stress relief, with the provision of a softer tip portion 46, the stiffness increases over the length of the dome cap unit 45. At the opposite end from the softer protruding tip portion 46, the bend stress relief preferably terminates into a rigid end portion. The rigid end portion can be an integral part of the at least one stabilizing base 24, 25 (not shown in the middle), or, the rigid end portion is connected to the at least one stabilizing base 24, 25 by a rigid support frame, as shown in Figure 6 . Figure 6 ​

[0282] This arrangement is like the rigid termination of a traditional bend stress relief / end reinforcement. In the case of an arrangement where the base is a rigid metal flange, the stiffness of the bend stress relief / end reinforcement is designed to provide a flexible section, for example a flexible streamer, umbilical, cable or line, with a predetermined curvature that depends on the force and angle at which the flexible section is pulled (usually displayed in polar form). In order for the flexible streamer, umbilical, cable or line to have a sufficiently long fatigue life, the bend management system must meet its design limits as well as the fatigue curvature and tension pairs.

[0283] This can be provided by a dome-shaped cover unit 45, which itself is kept sufficiently increased in stiffness over its length, or the dome-shaped section can be assisted by a flexible support or damping device, such as shown in Figure 6 , between the distal end and the rigid end, so that the overall management system provides a sufficiently low curvature of the flexible streamer, umbilical, cable or line to provide a sufficient fatigue life.

[0284] The nature of the stabilizing device 22 only allows 180 degrees of free movement in the upper part. The trajectory of the seabed 17 (or scour protection 15) and the submarine cable unit 22 from the foundation interface will limit the movement of the submarine cable unit to the side (omni-directional) and upwards (heave). Therefore, the dome-shaped distillation cover unit 45 must only manage the dynamic movement of the submarine cable unit 18 in these directions.

[0285] Figure 7 and Figure 8 A stabilizing plane of at least one stabilizing base 24, 25 is shown, which is provided with integral through-holes 42 for pile elements 54 in the open structure. The through-holes 42 can be provided with one or more guide elements 43 Figure 6 and Figure 7 (not shown in Figure 22 ), to facilitate the insertion of the pile elements 6 into the holes.

[0286] The horizontal part 48 of the dome-shaped cover unit 45 is designed to hold the submarine cable unit 18 towards the seabed 17 (or scour protection 15), as described below.

[0287] Alternatively, at least one stabilizing base 24, 25 can be provided on only one side of the cover unit 45, and the number of through-holes 42 for pile elements 54 can be one or more as described above.

[0288] Alternatively, on both sides of the cover unit 45, stabilizing bases 24, 25 can be provided. Also, the number of through holes 42 for pile elements 54 in the stabilizing bases 24, 25 can be one or more.

[0289] In another alternative, as shown in Figure 9 , on both sides of the cover unit 45, two stabilizing bases 24, 25 can be provided.

[0290] As shown in Figures 10 to 11 , the stabilizing bases 24, 25 can be designed without designated through holes 42 for pile elements 54. Instead, one or more loose clamping elements 39 can be used, each comprising at least one through hole 42 for pile elements 54.

[0291] The clamping elements 39 are provided with recesses 40 for arresting at least one stabilizing base 24, 25, or the clamping elements 39 are provided with a combination in which recesses 40 or slots in at least one stabilizing base 24, 25 can be formed with a docking for a tap-like piece located on the clamping element 39 (or reversely, a protrusion of at least one stabilizing base 24, 25 can fit into a recess 40, a recess or a slot of the clamping element 39.

[0292] Alternatively, as shown in Figure 12 , at least one stabilizing base 24, 25 can be held by a clamping element 39 in the form of a clamp comprising at least one through hole 42 for pile elements 54.

[0293] As shown in Figure 13 and Figure 14 , as an alternative to the flexible first clamping means 27, depending on whether the stabilizing means 22 are provided with two or one stabilizing base 24, 25, respectively, the cover unit 45 of the bending management system can be supported by a double absorber device 30 as shown in Figure 14 or a single absorber device 30 as shown in Figure 13 , to derive a preferred curvature. The absorber device 30 can be anchored on one end to a first anchoring portion 31 on a single stabilizing base 24, 25 as shown in Figure 13 or to both stabilizing bases 24, 25 as shown in Figure 14 , and on the other end to a second anchoring portion 24 on the cover unit 45.

[0294] With respect to the bend management system for the bend relief / end reinforcement, traditionally, the flexible piece is mechanically terminated to a fixed piece, reinforcing the end of the bend relief / end reinforcement - the stabilizing device 22 is preferably adapted to hold the submarine cable unit 18 in its longitudinal direction. This is to ensure that dynamic movements on the chain of submarine cable units do not force the submarine cable unit 18 to reposition. This feature also ensures that tension in the submarine cable unit 18 is not transmitted to the submarine cable unit 18 on the other side of the stabilizing device 22.

[0295] As shown in Figure 15 and Figure 16 , the longitudinal holding of the submarine cable unit 18 can be obtained by a movement stopping element 51, for example in the form of a high friction layer inside the horizontal portion 48 of the dome-shaped cover unit 45. The entire top of the cover unit 45 can be fitted with a high friction material or substance (for example, but not limited to, natural rubber, neoprene, preferably hardness grades 67, 73 and 78).

[0296] The friction force can also be provided by a movement stopping element 51 in the form of a panel or friction pad inside the dome-shaped top of the cover unit 45, as shown in Figure 15 and Figure 16 , the movement stopping element 51 compresses against the submarine cable unit 18 when the dome-shaped cover unit 45 is stabilized to the seabed 17 or scour protection layer 15. Thus, the submarine cable unit 18 is forced against the friction pad after it has descended onto the cable protection system 20 of the submarine cable unit 18 according to the vertical base force on at least one stabilizing base 24, 25. This increases the friction force and protects the submarine cable unit 18 from sliding and from transmitting tension from the stabilizing device 22.

[0297] Alternatively, as shown in Figure 17 , the submarine cable unit 18 can be held inside the dome-shaped cover unit 45, preferably inside the horizontal portion 48 of the cover unit 45, which has a movement stopping element 51 in the form of a slot / cavity / recess / groove adapted to interface with a specific length portion of the submarine cable unit 18.

[0298] As shown in Figure 18 , the stabilizing device 22 can be positioned near or on top of the touchdown point 34 of the submarine cable unit 18. In this figure, the stabilizing device 22 is shown centered on top of the touchdown point of the submarine cable unit 18. This would require a high level of installation precision. To allow freedom of installation position with respect to the touchdown point 34 of the submarine cable unit 18, the flexibility of the bend management system accommodates a wide tolerance.

[0299] In Figure 19In this case, the central part 31 of the stabilizing device 22 is positioned outside the touchdown point 34 of the submarine cable unit 18. The capacity of the bend management system can be designed to accommodate the required maximum horizontal external positioning.

[0300] Alternatively, the central part 35 of the stabilizing device 22 can be positioned inside the touchdown point 34 of the submarine cable unit 18. The capacity of the bend management system can be designed to accommodate the required minimum horizontal internal positioning.

[0301] As Figure 20 shown, this facilitates a greater freedom of horizontal positioning of the stabilizing device 22 on top of the submarine cable unit 18, as shown by the two alternative positions of the central part 35 of the stabilizing device 22. This horizontal freedom also allows a variable cable protection system and cable direction (compass direction).

[0302] As Figure 21 shown, for an open alternative of the stabilizing base 2, a box-like first stabilizing base 24 and a second stabilizing base 25 can be provided on each side of the cover unit 45 of the bend management system on top of the submarine cable unit 18.

[0303] wherein one or more pile elements 54 extend from the top of the stabilizing base 2, for example through the scour protection layer 15, to a depth of the stabilizing seabed shown by reference 17.

[0304] As Figure 22 shown, the through hole 42 for the pile element 54 located in at least one stabilizing base 24, 25 can be equipped with a guide element 43 to assist the pile element 54 in entering the respective through hole 42.

[0305] As Figure 23 shown, in the case of a driven foundation type, i.e. pile elements 54 or screws, etc., the compression system of the stabilizing device 22, including the expansion device 59, can be compressed from a relaxed state 61 with the expansion device 59 having an uncompressed length to a compressed state 60 with a compressed length. Alternatively, the expansion device 59 can be applied to its compressed length to have the ability to expand to its uncompressed length.

[0306] In the case of a movement of the seabed 17, or in the case of a setting of the scour protection 15 to a deeper place of the seabed 17, the compressed installed length of the expansion device 59 can expand from the compressed length of the expansion device to the full length of the expansion device 59. This expansion length is the vertical lowering capacity of the stabilizing device that can follow a lowering of the seabed 17 or the scour protection 15.

[0307] As Figure 24As shown, the compressed expansion device 59 releases its expansion as force downward to the at least one stabilizing base 24, 25 and upward to the top 56 of the pile element 54. In this figure, the stabilizing device 22 is shown in the seabed 17 without scour protection 15, with the scour pit / hole 16 extending adjacent the monopile 12.

[0308] Figure 25 As shown: from the installation level 36 of the stabilizing device 22 (which is the position of the seabed level at the time of installation), to the first chain 52 of the submarine cable unit 18, through the compressed expansion device 59, the stabilizing device 22 will follow the lowering of the seabed level all the way to the lowered level of the stabilizing device 22, during which the expansion device 59 will extend from the compressed state 60 to a more relaxed state 61 with a new expanded length, thereby forcing the at least one stabilizing base 24, 25 to move from the installation level 36 of the stabilizing device 22 to the lowered level 37 of the stabilizing device 22 to the new lowered seabed level, in turn forcing the submarine cable unit 18 to enter a new second chain 53 shape.

[0309] This will move the touch point 34 of the natural chain shape of the submarine cable unit 18, but the capacity of the bend management system remains in control of this, despite the higher tension on the chain 53 of the second submarine cable unit.

[0310] In Figure 26 , the initial seabed 17 of the stabilizing device 22 is shown (the state and position of the seabed 17 at the time of installation of the stabilizing device 22). The at least one stabilizing base 24, 25 is provided on the submarine cable unit 18 in the shape of the first chain 52, fixed in the seabed by the pile element 54, with the expansion device 59 in its compressed state 60.

[0311] As Figure 27 shown, in the case of a lowering of the seabed / anti-scour level, the pile element 54 - the top portion 9 and the submerged lower portion 55 - remains unchanged. Thus, when the seabed 17 is lowered, the at least one stabilizing base 24, 25 follows the level of the seabed 17 due to the expansion of the compressed expansion device 59, thereby causing the height of the top portion 56 of the pile element 54 to uniformly rise above the at least one stabilizing base 24, 25 as the level of the seabed 17 is lowered.

[0312] The expansion device 59 can preferably be provided with a compression spring (as described above and shown in the drawings), or the expansion device 59 can be provided with any expansion material that can be installed or compressed in its retracted form. Thus, a mechanical limit can be stopped after installation (degradable after a predetermined time after immersion, or immersion in seawater promotes expansion of the base material).

[0313] As Figure 28 andFigure 29 As shown, the bending management system of the stabilizing device 22 can be configured as, for example, a bending stress-relieving type bending stiffener known according to API 17. The bending stress-relieving base 68 is fixedly or alternatively coupled to the stabilizing base 70. As the bending stiffness increases, the bending stiffener portion 69 of the bending management system provides the required continuously increasing bending stiffness from the slightly raised end (where the bending stiffness is minimal) to the solid base.

[0314] The bending stress relief device can be pre-installed on the cable protection system before being pulled in. An alternative and preferred method is to use an open slotted bending stress relief base 68 and a bending reinforcement portion 69, allowing the stabilizing device 22 to be placed on top of the submarine cable unit 18. In addition to the advantage of separating the installation operation of the stabilizing device 22 from its operation on the cable highway of the critical path and CLS, this also allows for stabilization of the stabilizing device 22 on the already installed submarine cable unit 18.

[0315] like Figures 30 to 31 As shown, the bend management system can alternatively be configured to gradually restrict the free movement of the submarine cable unit 18. The bend management system can be configured as a flared semi-cone 72, preferably, the flared semi-cone 72 comprising a series of rods 73 according to its internal shape, its structural stiffness, or any combination thereof. Preferably, the device can employ a single or more rigid rods or a similar arrangement to provide an area for tensile strain management.

[0316] The longitudinal friction lip provides an upward force toward the friction pad / layer on the cable protection system 20 and provides slight deformation on both sides of the cable protection system to secure the gripper to the smooth surface of the cable protection system.

[0317] like Figure 32 As shown, the stabilizing device 22 may be provided with a deformation device 64, which causes the outer surface of the cable protection system 20 of the submarine cable unit 18 to deform in the positive direction, so as to strengthen the longitudinal restraint alone or together with any other motion-stopping element 51, such as the friction pad / layer as described above.

[0318] The transverse struts 65 (e.g. three on each side, but there can be one or more transverse struts 65) are arranged transversely relative to the longitudinal direction of the cover unit 45 and are fixedly attached at one end to the cover unit 45 at respective attachment points 67 and will be pushed down by the pile element 54 and its expansion means 59 onto the first and second stabilising base 24, 25. The other end of the transverse struts 65 is connected to a compression area 66 or pad area provided on the first and second stabilising base 24, 25. When the transverse struts 65 are not compressed, the compression area 66 is held in a substantially horizontal position, so that the compression area 66 is mounted on the cable protection system 20 of the submarine cable unit 18.

[0319] When the pile element 54 exerts pressure on the transverse struts 65 and in turn on the first and second stabilising base 24, 25, the other end of the transverse struts 65 is pushed against the surface of the cable protection system 20 of the submarine cable unit 18, as shown in Figure 33 This provides a tight grip on the outer surface of the cable protection system 20, so that any movement of the submarine cable unit 18 is prevented.

[0320] In Figures 34 to 4 0, an alternative foundation arrangement 74 for a submarine cable unit 18 is shown, which foundation arrangement 74 only comprises the cable or the cable provided with a cable protection system to mitigate a lowering of the seabed 17 and / or scour protection layer 15 without changing the shape of the chain of the already installed submarine cable unit 18. This lowering of the seabed and / or scour protection layer can be caused by local seabed erosion or scouring below the submarine cable unit 18, but also by erosion or scouring of the global seabed in the area around the submarine cable unit 18.

[0321] The alternative foundation arrangement 74 also has the advantage that it enables the submarine cable unit 18 to be installed in a position in which the erosion has resulted in a free-span between the touch-down point of the submarine cable unit 18 at the time of its laying and the original uneroded seabed level or scour layer level. Thus, the alternative foundation arrangement 74 enables the submarine cable unit 18 to be installed with the submarine cable unit 18 suspended above the level of the seabed 17 or scour protection layer 15, thereby providing an artificial touch-down base for the submarine cable unit 18 which is raised above the level of the seabed or scour protection layer without changing the shape of the chain, thereby changing the tension in the submarine cable unit 18.

[0322] The foundation arrangement 74 can also be used in situations in which erosion is expected to occur due to local current conditions. In this case, the foundation arrangement 74 is installed prior to or in the same installation process as the submarine cable unit 18.

[0323] In Figure 34The image shows a submarine cable unit 18, which is installed and extends from above the seabed 17 or the scour protection layer 15, for example, from a seabed structure (not shown) to the seabed 17 or the scour protection layer 15.

[0324] Over time, the seabed 17 and / or the erosion protection layer 15 may erode, and the submarine cable unit 18 may eventually become suspended above the seabed 17 or the erosion protection layer 15. This is in Figure 35 and Figure 38 As shown, the submarine cable unit 18 is located at a distance D above the seabed 17 or the scour protection layer 15. This will increase the tension in the submarine cable unit 18 and may cause changes in the chain shape of the submarine cable unit 18, thereby increasing the wear of the submarine cable unit 18.

[0325] exist Figures 36 to 4 Figure 0 shows a base device 75, which can be used to mitigate corrosion problems of the seabed 17 and / or scour protection layer 15 around the submarine cable unit 18.

[0326] exist Figure 36 Two foundation devices 75 are shown, each foundation device 75 including a pile element 75 having: a lower portion 79 disposed in the seabed 17 and / or scour protection layer 15; an upper portion 76; and a free portion 78 located between the lower portion 79 and the upper portion 76.

[0327] The upper portion 76 of the pile element 75 is provided with an attachment unit 77. The attachment unit 77 is securely attached to the pile element 75 by a suitable means such as bolts or by welding.

[0328] Each base unit 74 also includes a support element 80, which is attached to the attachment unit 77 and supports the submarine cable unit 18. Preferably, the support element 80 is attached to the attachment unit 77 in an adjustable manner, but it can also be securely attached to the attachment unit by bolts or any other suitable fastening device. To achieve an adjustable position of the support element 80 on the attachment unit 77, the support element 80 and the attachment unit 77 may be provided with corresponding threads, allowing the support element 80 to be screwed up and down onto the attachment unit 77 to a desired position. When the support element 80 is in its desired position, the support element 80 can be locked to the attachment unit 77 by a suitable locking mechanism (not shown).

[0329] The support element 80 is preferably provided with a support element support surface 81 which is shaped in a conical manner as shown in the figures. Since the pile element 75 is arranged in the seabed 17 and / or scour protection layer 15 inclined with respect to the vertical, the angle of the conical support element support surface 81 can be adapted to the angle of the inclination of the pile element 75 so that the submarine cable unit 18 rests on a substantially horizontal surface.

[0330] As can be clearly seen from Figure 36 the two foundation devices have been installed inclined with respect to each other and inclined with respect to the seabed 17 or scour protection layer 15 so that the two foundation devices form a pair of scissors. Furthermore, the submarine cable unit 18 rests on the support element support surface 81 of the support element 80.

[0331] Figure 37 and Figure 38 The installation of the bend stiffener unit 85 is also shown. The bend stiffener unit 85 comprises a bend stiffener body 86 which has a roughly semi-dome shaped cross section and which fits on top of the submarine cable unit 18. In Figure 38 is clearly shown that the submarine cable unit 18 is supported by the support element 80 at a distance D above the level of the seabed 17 or scour protection layer 15.

[0332] The bend stiffener unit 85 further comprises four attachment elements 87 which are firmly attached to the bend stiffener body 86 and which extend outwardly therefrom as indicated in the figures. Two attachment elements 87 are provided on one side of the bend stiffener body 86 as indicated in the figures. The distance between the two attachment elements 87 located on the same side of the bend stiffener body 86 in the longitudinal direction of the bend stiffener body 86 is adjusted so that the attachment elements 77 and the locking element 82 fit in the space between the two attachment elements 87.

[0333] The bend stiffener unit 85 will control the bending of the submarine cable unit 18 when installed and reduce the risk of damage to the submarine cable unit 18.

[0334] Figure 39 and Figures 40a to 40b The bend stiffener unit 85 provided on top of the submarine cable unit 18 is shown. As described above, the bend stiffener body 86 of the bend stiffener unit 85 is semi-dome shaped and fits on top of the submarine cable unit 18.

[0335] When the bend stiffener unit 85 is arranged on top of the submarine cable unit 18, the locking element 82 is arranged on the attachment unit 77 such that the bend stiffener unit 85 is locked in its position and thus the submarine cable unit 18 is locked in its position.

[0336] Preferably, the locking element 82 is adjustably arranged on the attachment unit 77 along the longitudinal direction of the pile element 75. The locking element 82 and the attachment unit 77 can for example be provided with corresponding threads such that the locking element 82 can be screwed up and down along the attachment unit 77 to a desired position at which the bend stiffener unit 85 is locked to its position on top of the submarine cable unit 18. When the locking element 82 is arranged in its desired position, the locking element 82 can be locked to the attachment unit 77 by a suitable locking mechanism (not shown in the figures).

[0337] Preferably, the attachment element 87 is wedge-shaped and provided with an attachment element contact surface 88 as indicated in the figures. Furthermore, the locking element 82 has a conical locking element contact surface 83 and after installation of the bend stiffener unit 85 this locking element contact surface 83 abuts the attachment element 87 on the opposite side of the locking element 82. The wedge-shaped attachment element 87 ensures a favorable angle and thus a better cooperation between the locking member contact surface 83 and the attachment element contact surface 88.

[0338] Reference signs used in the description of the figures:

[0339]

[0340]

[0341]

Claims

1. A stabilizing device (22) for a submarine cable unit (18) extending between a cable inlet (13) on a seabed (17) and a subsea structure (11), wherein, The cable inlet (13) is located above the seabed (17), wherein the submarine cable unit (18) includes a submarine cable with a cable protection system (20) or only a submarine cable, and wherein the stabilizing device (22) includes: -At least one stable base (24, 25), - A first clamping device (27) is securely attached at one end to the at least one stabilizing base (24, 25). The first clamping device (27) is curved and adapted to at least partially surround the submarine cable unit (18), and holds the submarine cable unit (18) when the at least one stabilizing device (22) and the submarine cable unit (18) are installed. - A second clamping device (28), which is securely attached at one end to the at least one stabilizing base (24, 25), is curved and adapted to at least partially surround the submarine cable unit (18), and holds the submarine cable unit (18) when the stabilizing device (22) and the submarine cable unit (18) are installed. - At least one pile element (54) for anchoring the at least one stabilizing base (24, 25) to the seabed (17) or to the scour protection layer (15), the at least one pile element (54) being adapted to be driven into the seabed (17) or the scour protection layer (15) such that when the stabilizing device is installed, the at least one stabilizing base (24, 25) is firmly anchored to the seabed (17) or the scour protection layer (15), and such that the stabilizing device (22) is positioned on top of the contact point (34) of the submarine cable unit (18).

2. The stabilizing device according to claim 1, in, The first clamping device (27) and the second clamping device (28) are attached to the at least one stabilizing base (24, 25) such that the first clamping device (27) is closer to the seabed structure (11) than the second clamping device (28), and wherein the first clamping device (27) is flexible.

3. The stabilizing device according to claim 1 or 2, in, The second clamping device (28) is more rigid than the first clamping device (27).

4. The stabilizing device according to any one of claims 1 to 3, in, The at least one stabilizing base (24, 25) includes at least one through hole (42), and the at least one pile element (54) is adapted to pass through the at least one through hole (42).

5. The stabilizing device according to any one of claims 1 to 4, in, The stabilizing device (22) includes at least one clamping element (39), which includes at least one through hole (42) for the at least one piling element (54).

6. The stabilizing device according to any one of claims 1 to 5, in, The at least one pile element (54) is provided with an expansion device (59) that applies a force toward the seabed (17) or the scour protection layer (15) on the at least one stabilizing base (24, 25).

7. The stabilizing device according to claim 6, in, The expansion device (59) is adapted to expand in the event that the seabed (17) or the scour protection layer (15) is corroded, so as to continuously apply a force toward the seabed (17) or the scour protection layer (15) on the at least one stabilizing base (24, 25).

8. The stabilizing device according to claim 6 or 7, in, The at least one pile element (54) is provided with an adjustment device (62) for adjusting the tension in the expansion device (54) and thereby adjusting the force applied to the at least one stabilizing base (24, 25).

9. The stabilizing device according to any one of claims 1 to 8, in, The stabilizing device (22) further includes a cover unit (45) for bending control of the submarine cable unit (22), wherein the cover (45) is bent and at least partially surrounds the submarine cable unit (22) in the circumferential direction, and the cover unit (45) and the submarine cable unit (22) are held by the first clamping device (27) and the second clamping device (28).

10. The stabilizing device according to claim 9, in, The cover unit (45) is also bent in the longitudinal direction of the submarine cable unit (22) to prevent the cable from bending beyond the desired angle.

11. The stabilizing device according to claim 9 or 10, in, The cover unit (45) has at least one motion-stopping element (51) on the side facing the submarine cable unit (22), wherein the at least one motion-stopping element (51) presses against the submarine cable unit (22).

12. The stabilizing device according to any one of claims 1 to 11, in, The stabilizing device (22) includes a first stabilizing base (24) and a second stabilizing base (25), each of the first stabilizing base (24) and the second stabilizing base (25) including at least one through hole (42) for at least one pile element (54), the at least one pile element (54) being adapted to be fitted into the at least one through hole (42) and driven into the seabed (17) or the scour protection layer (15), such that the first stabilizing base (24) and the second stabilizing base (25) can be firmly anchored to the seabed (17) or the scour protection layer (15).

13. The stabilizing device according to claim 12, in, The first clamping device (27) is securely attached to the first stabilizing base (24) at one end and to the second stabilizing base (25) at the other end, and the second clamping device (28) is securely attached to the first stabilizing base (24) at one end and to the second stabilizing base (25) at the other end.

14. The stabilizing device according to any one of claims 1 to 13, in, The first clamping device (4) includes at least one dynamic absorber device (30) which is anchored at one end to the first stabilizing base (24) and / or the second stabilizing base (25) and at the other end to the cover unit (45).

15. The stabilizing device according to any one of claims 12 to 14, in, The first stabilizing base (24) and / or the second stabilizing base (25) are provided with a plurality of through holes (42) for pile elements (54), the pile elements (54) being adapted to be fitted into the corresponding through holes (42) and driven into the seabed (17) or the scour protection layer (15), so that the first stabilizing base (24) and / or the second stabilizing base (25) can be firmly anchored to the seabed by the plurality of pile elements (54).

16. The stabilizing device according to claims 4 to 15, in, The at least one through hole (42) is provided with a guide element (43) to facilitate the entry of the at least one pile element (54) into the at least one through hole (42) during the installation of the stabilizing device (22).

17. The stabilizing device according to any one of claims 1 to 16, in, The at least one pile element (54) is adapted to be operated by an ROV.

18. The stabilizing device according to any one of claims 1 to 17, in, The submarine cable unit (22) is equipped with a cable protection system (20).

19. The stabilizing device according to any one of claims 1 to 18, in, The seabed structure (11) is securely installed in or to the seabed (17).

20. A subsea system (10), the subsea system (10) comprising: A subsea structure (11) securely mounted in or to the seabed (17); and a subsea cable unit (18) extending between the seabed (17) and a cable inlet (13) on the subsea structure (11), wherein the cable inlet (13) is located above the seabed (17), wherein the subsea cable unit (18) comprises a subsea cable with a cable protection system (20) or comprises only a subsea cable, and wherein the subsea system (10) includes a stabilizing device (22) according to any one of claims 1 to 19 for stabilizing the subsea cable unit (18).

21. The subsea system according to claim 20, in, The stabilizing device (22) is disposed on the scour protection layer (15), which is disposed on the seabed (17) adjacent to the seabed structure.

22. The subsea system according to claim 20, in, The stabilizing device (22) is directly mounted on the seabed (17).

23. The subsea system according to any one of claims 20 to 22, in, The subsea structure (10) is a monopile (12) for a wind power station, which is securely installed to the seabed (17) or in the seabed (17).

24. Use of a stabilizing device (22) according to any one of claims 1 to 19 and / or a subsea system (10) according to any one of claims 20 to 23 for stabilizing a subsea cable unit (18) from an offshore wind farm.

Images