CN118098680A - Submarine cable for offshore wind power - Google Patents

Abstract

The present invention relates to a submarine cable for offshore wind power, which has improved water tree characteristics. And more particularly, to a submarine cable for offshore wind power, which can effectively suppress the diffusion of moisture permeated into the core of the cable into an insulating layer to form a water tree, thereby improving dielectric strength and consequently ensuring long service life.

Description

Submarine cable for offshore wind power

Technical Field

The present invention relates to a submarine cable for offshore wind power, which has improved water tree characteristics. And more particularly, to a submarine cable for offshore wind power, which can effectively suppress the formation of water trees due to the diffusion of moisture penetrating into the core of the cable into an insulating layer, thereby improving dielectric strength and consequently ensuring long service life.

Background

In the case of submarine cables, which have been laid long before for the purpose of power transmission in island regions and communication connection between continents, offshore wind power in which wind power generators are installed at sea has many advantages over land wind power in terms of wind conditions, foundation assurance, noise problems, and the like, and thus, the construction of offshore wind power regions continues to increase, and attention to submarine cables for offshore wind power is growing.

In an offshore wind power region, a submarine cable for offshore wind power is connected to land from a wind turbine or an offshore substation provided at sea, and the submarine cable for offshore wind power is fixed to and laid on the ground of the sea floor in sections or is separated from the ground of the sea floor to be connected to the wind turbine or the offshore substation at sea.

Since the submarine cable for offshore wind power is laid in a submarine environment, it is necessary to ensure water blocking performance for suppressing penetration and diffusion of moisture into the cable, and the submarine cable for offshore wind power laid in a fixed area on the ground of the seabed is called Export Type, and since the metallic sheath layer based on lead is provided, penetration of moisture can be suppressed.

However, since it is necessary to secure a movement or bending due to a current or a wave in a submarine cable for offshore wind power connected to a wind turbine or a transformer station at sea by being separated from the ground of the sea floor, it is difficult to use a lead metal sheath layer for preventing the movement or bending, and such a submarine cable for offshore wind power is called Inter-ARRAY TYPE (buried-array type).

The offshore wind power submarine cable of Inter-ARRAY TYPE may be classified into Dry type, semi-wet type and wet type according to whether it is sheathed or not. Dry type has a metal sheath layer composed of lead, semi-wet has a polymer sheath, and wet type is in a non-sheath state. In the case of the lead-sheath-based metal sheathing member, moisture may penetrate into the inside of the cable, and the penetrated moisture diffuses into the insulating layer of the core, thereby forming a water tree, thus reducing dielectric strength, with the result that the life of the cable is reduced. Conventionally, in order to suppress penetration and diffusion of moisture, a shield layer made of a metal wire has been used in place of a lead metal sheath layer for a submarine cable for offshore wind power, but it has been difficult to suppress penetration of moisture into an insulating layer.

Therefore, there is a strong need for a submarine cable for offshore wind power that can effectively suppress the diffusion of moisture penetrating into the core of the cable into the insulating layer to form a water tree to improve dielectric strength, and as a result, can secure a long service life.

Disclosure of Invention

The purpose of the present invention is to provide a submarine cable for offshore wind power, which has improved dielectric strength by effectively suppressing the diffusion of moisture penetrating into the core of the cable into the insulating layer to form a water tree, and as a result, can secure a long service life.

In order to solve the above problems, the present invention provides an offshore wind power submarine cable comprising one or more cores including a conductor and an insulating layer surrounding the conductor, wherein the water tree size inside the insulating layer is 850 μm or less as measured by standard ASTM D6097.

The submarine cable for offshore wind power is characterized in that the insulating layer has a crosslinking degree of 77% or more and a crystallinity of 35% or more.

Further, there is provided a submarine cable for offshore wind power, wherein the insulating layer comprises cross-linked polyethylene (XLPE).

Further, there is provided a submarine cable for offshore wind power, wherein the insulation layer has an insulation breakdown voltage (BDV) of 80kV/mm or more.

In another aspect, there is provided a submarine cable for offshore wind power, wherein the core comprises a conductor, an inner semiconductive layer surrounding the conductor, an insulating layer surrounding the inner semiconductive layer, an outer semiconductive layer surrounding the insulating layer, a wire shielding layer surrounding the outer semiconductive layer, and a core armor surrounding the wire shielding layer.

Further, there is provided a submarine cable for offshore wind power, comprising: an inner water stop tape layer surrounding the outer semiconductive layer between the outer semiconductive layer and the line shield; an outer water-stop tape layer surrounding the wire shield layer; and a metal sheath layer surrounding the outer water-stop tape layer.

The submarine cable for offshore wind power is characterized in that the external water-stop adhesive tape layer comprises at least one selected from the group consisting of powder containing super absorbent resin (super absorbent polymer; SAP), adhesive tape, coating and film.

The submarine cable for offshore wind power is characterized by comprising a plurality of cores, and filling members are arranged in the central part and the outer area of the cores.

There is provided a submarine cable for offshore wind power, wherein the filler member comprises a polypropylene Yarn (Yarn).

Further, there is provided a submarine cable for offshore wind power, characterized in that a binding tape layer for ending a plurality of cores and filler members in a circular shape is provided, and an armor layer for mixing polypropylene yarn and asphalt (bitumen) is further included on the outer side of the binding tape layer.

The submarine cable for offshore wind power is characterized in that a metal armor layer is arranged on the outer side of the armor layer, and an anti-corrosion layer which is formed by mixing polypropylene yarns and asphalt (bitumen) is further arranged on the outer side of the metal armor layer.

The submarine cable for offshore wind power according to the present invention has an excellent effect of ensuring a long-term service life by improving dielectric strength by adjusting the water tree size to a specific size or less through precise control of the crosslinking degree and crystallinity of the insulating layer.

Drawings

Fig. 1 is a transverse cross-sectional view schematically showing a cross-sectional structure of an embodiment of a submarine cable for offshore wind power of the present invention.

Fig. 2 is a longitudinal sectional view of one core of the offshore wind power submarine cable shown in fig. 1.

1000: Submarine cable for offshore wind power

100: Light unit

300: Core(s)

400: Filling member

500: Binding adhesive tape layer

600: Armoured cushion layer

700: Metal armor layer

800: Corrosion-resistant layer

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments described herein and may be implemented in other forms. Rather, the embodiments described herein are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Like reference numerals refer to like elements throughout the specification.

Fig. 1 is a transverse cross-sectional view schematically showing a cross-sectional structure of one embodiment of the offshore wind power submarine cable of the present invention, and fig. 2 is a longitudinal cross-sectional view of one core of the offshore wind power submarine cable shown in fig. 1.

As shown in fig. 1, the offshore wind power submarine cable 1000 according to the present invention may be a three-phase ac power cable in which three cores 300a, 300b, 300c are arranged in a delta configuration. In order to construct the three cores 300a, 300b, 300c in a circular shape, a filling member 400 of a fiber material may be provided in the central portion and the core outer side region. At least one light unit 100 having a plurality of light fibers may be accommodated and mounted in the filling member 400.

Here, the light unit 100 may have at least one optical fiber 110 and a tube 120 accommodating the optical fiber 110. The individual light units 100 have a prescribed number of optical fibers 110 mounted together with a filler material within a tube 120, which may use a rigid material such as stainless steel. The light unit 100 may also have a sheath 130 surrounding the tube 120.

Typically, the filling member 400 is mainly made of polypropylene Yarn (Yarn). When the cores 300a, 300b, 300c, the light units, and the yarns are combined to form the offshore wind power submarine cable, they may be combined at a predetermined pitch into a circular shape. The filler member 400 made of a fiber material is provided for waterproofing and forming a circular shape, and may be formed in the form of an intermediate member (INTERVENING MEMBER) made of a resin material which is extruded, instead of the filler member 400. In this case, the light unit may be configured to be inserted and accommodated inside an intervening member (not shown).

Furthermore, a tie-down tape layer 500 may be provided, said tie-down tape layer 500 being used to terminate the three cores 300a, 300b, 300c and the filling member 400 in a circular shape. An armor pad 600 may be provided at the outside of the binding tape layer 500. The armor pad 600 serves to provide a mounting surface for the metal armor 700 provided on the outer side thereof.

Here, the armor layer 600 may be formed by mixing Polypropylene (PP) yarn and asphalt (bitumen). A metal armor layer 700 may be provided on the outer side of the armor pad 600, and the metal armor layer 700 may be provided with armor wires 710, thereby functioning to protect the offshore wind power submarine cable in a rough submarine environment.

As in the case of the armor layer 600, an anticorrosive layer 800 formed by mixing Polypropylene (PP) yarn and asphalt (bitumen) is provided on the outer side of the metal armor layer 700, whereby a submarine cable for offshore wind power can be completed.

As shown in fig. 1 and 2, the core 300 may include, in order, a conductor 310, an inner semiconductive layer 320, an insulating layer 330, an outer semiconductive layer 340, an inner water stop tape layer 350, a wire shield layer 360, an outer water stop tape layer 370, a metal jacket layer 380, and a core armor 390, among others.

The conductor 310 functions as a path through which power flows to transmit power, and may be composed of a material having excellent conductivity such as copper or aluminum, strength and flexibility suitable for cable manufacture and use to minimize power loss.

The conductor 310 may be a round compressed conductor in which a plurality of round wires are twisted and compressed into a round shape, and has a flat conductor having a round cross section as a whole, which is formed of a round center wire and a flat wire layer twisted into a flat wire surrounding the round center wire, and has a relatively high occupancy (occupying ratio) compared to the round compressed conductor, thus having an advantage of being able to reduce the outer diameter of the cable.

However, since the surface of the conductor 310 is not smooth, the electric field may be uneven, thereby easily generating corona discharge. In addition, if a gap is generated between the surface of the conductor 310 and the insulating layer 330 described later, an electric field may concentrate in the gap, resulting in a decrease in insulating properties.

Accordingly, an inner semiconductive layer 320 may be disposed on the exterior of the conductor 310. The inner semiconductive layer 320 may be semiconductive by adding conductive particles such as carbon black, carbon nanotubes, carbon nanoplates, graphite to a base resin such as Ethylene-vinyl acetate (EVA: ETHYLENE VINYL ACETATE), ethylene methyl acrylate (EMA: ETHYLENE METHYL ACRYLATE), ethylene methyl methacrylate (EMMA: ETHYLENE METHYL METH ACRYLATE), ethylene ethyl acrylate (EEA: ETHYLENE ETHYL ACRYLATE), ethylene ethyl methyl acrylate (EEMA: ETHYLENE ETHYL METH ACRYLATE), ethylene (iso) propyl acrylate (EPA: ethyl (iso) propyl acrylate), ethylene (iso) propyl methacrylate (EPMA: ethyl (iso) propyl METH ACRYLATE), ethylene butyl acrylate (EBA: ethylene butyl acrylate), ethylene butyl methyl acrylate (EBMA: ethyl butyl METH ACRYLATE), and the like.

The inner semiconductive layer 320 functions to stabilize insulation performance by preventing abrupt electric field changes from occurring between the conductor 310 and an insulation layer 330, which will be described later. In addition, the electric field can be made uniform by suppressing uneven charge distribution of the conductor surface, and corona discharge, insulation breakdown, and the like can be suppressed by preventing formation of a void between the conductor 310 and the insulating layer 330.

In addition, the inner semiconductive layer may contain 0.1 to 5 parts by weight of a crosslinking agent based on 100 parts by weight of the base resin. Since a crosslinking byproduct generated at the time of crosslinking of the inner semiconductive layer may permeate into the insulating layer 330 to function as a crystal nucleus, it is necessary to adjust the crosslinking agent content of the inner semiconductive layer.

The insulating layer 330 is disposed outside the inner semiconductive layer 320 and electrically insulates the inner semiconductive layer 320 from the outside to prevent current from leaking along the conductor 310 to the outside. In general, the insulating layer 330 is required to have a high breakdown voltage and to be able to stably maintain insulating properties for a long period of time. Further, it is required to have thermal resistance properties such as heat resistance and less leakage loss.

Accordingly, the insulating layer 330 may be made of a polyolefin resin such as polyethylene and polypropylene, and preferably a polyethylene resin. The polyethylene resin may contain a crosslinking agent and be composed of XLPE (crosslinked polyethylene: crosslinked polyethylene) as a crosslinking resin, and the crosslinking agent may contain a peroxide crosslinking agent such as dicumyl peroxide, benzoyl peroxide, lauroyl peroxide, t-butylcumene peroxide, di (t-butylperoxyisopropyl) benzene, 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane, and di-t-butylperoxide. Further, the insulating layer may further contain other additives such as antioxidants, extrudability improvers, tree inhibitors, crosslinking aids, and the like.

An outer semiconductive layer 340 may be disposed on the exterior of the insulating layer 330. As the inner semiconductive layer 320, the outer semiconductive layer 340 may be formed to have a semiconductive substance by adding conductive particles such as carbon black, carbon nanotubes, carbon nano-plates, graphite, etc. to an insulating substance, thereby stabilizing insulating properties by suppressing uneven charge distribution between the insulating layer 330 and a line shielding layer 360 described later. In addition, in the cable, the outer semiconductive layer 340 alleviates electric field concentration by smoothing the surface of the insulating layer 330, thereby not only preventing corona discharge but also performing a function of physically protecting the insulating layer 330.

A wire shielding layer 360 may be disposed on the outside of the outer semiconductive layer 340. The wire shielding layer 360 is grounded at the end of the cable, functions as a path through which a fault current flows when an accident such as a ground current or a short circuit occurs, and also functions to protect the cable from external impact and to prevent an electric field from being discharged to the outside of the cable by shielding.

As shown in fig. 2, the wire shielding layer 360 may be formed of a material such as copper or copper-plated aluminum, and may be provided with shielding wires 361 laterally wound in a spiral shape at predetermined intervals of 0.2 millimeters (mm) to 2.0 millimeters (mm).

The wire shielding layer 360 may be provided with a metal shielding layer (not shown) formed in a spiral shape by transversely winding a metal tape on the outside thereof, thereby providing a fault current shunt function by energizing each shielding wire.

In addition, the core 300 may be further provided with at least one water-stop tape layer for absorbing moisture on the outside of the outer semiconductive layer 340. The water stop tape layer may be disposed at least one of the inside and outside of the aforementioned wire shielding layer 360. In the embodiment shown in fig. 1 and 2, the case where the inner water stop tape layer 350 and the outer water stop tape layer 370 are provided on the inner and outer sides of the wire shielding layer 360 is shown, but since moisture mainly permeates from the outer side, only the outer water stop water absorbing layer 370 may be provided.

The water-stop adhesive tape constituting the water-stop adhesive tape layer is constituted in the form of powder, adhesive tape, coating or film containing a super absorbent resin (super absorbent polymer; SAP) excellent in the ability to quickly absorb moisture permeated into the cable and to maintain the absorbed state in a swelled state, and functions to prevent permeation of moisture in the longitudinal direction of the cable. The water stop tape layer may also have semi-conductivity to prevent abrupt electric field changes. The thickness of the water stop tape layer may be 0.2 millimeters (mm) to 1.4 millimeters (mm).

In addition, a metal sheath layer 380 may be provided on the outside of the outer water stop tape layer 370. The metal sheath layer 380 is formed as a seamless continuous outer surface by extruding metal melted at the outer side of the outer water blocking tape layer 370, thereby enabling to improve water blocking performance. The masking layer may use Lead (Lead) or aluminum, and in particular, in the case of a submarine cable for offshore wind power, lead excellent in corrosion resistance against seawater is preferably used, and a Lead alloy (Lead alloy) to which a metal element is added is more preferably used to enhance mechanical properties.

In the case of a submarine cable for offshore wind power laid in an environment such as the ocean floor, it is possible to prevent deterioration of insulation performance due to invasion of foreign matter such as moisture by forming the metal sheath layer 380 to seal the core 300. In addition, in the case where the wire shielding layer 360, the water blocking tape layer, and the like are provided, the metal sheath layer 380 may be omitted because it has a certain degree of water blocking function.

A core armor 390 may be disposed on the outside of the metallic sheath 380. The core armor 390 constitutes the outermost portion of the core, and together with the metal sheath layer 380, enhances corrosion resistance, water stopping property, and the like, and plays a role of protecting the cable core from various environmental factors such as moisture permeation, mechanical trauma, corrosion, and the like, which can affect the power transmission performance of the cable, and from a fault current.

The core armor 390 may be constructed of a resin such as polyvinyl chloride (PVC), polyethylene (polyethylene), or the like. In this case, a polyvinyl chloride resin is preferably used in an environment where flame retardancy is required, and a polyethylene resin excellent in water-stopping property is preferably used in the case of the offshore wind power submarine cable of the present invention.

When the offshore wind power submarine cable shown in fig. 1 and 2 is laid on the sea floor, the submarine cable is always exposed to water pressure, and when the cable is damaged, the cable armor, the armor pad, the filler member, or the like can block the penetration of water at one time. However, moisture penetration into the inside of the core 300 cannot be permanently prevented, and therefore, a method of minimizing moisture diffusion is required together with the water stopping function of the core 300 itself when moisture penetration inevitably occurs.

The aforementioned wire shielding layer 360 functions as a path through which a fault current flows and protects the cable from external impact, and has a structure in which metal wires are arranged to be spaced apart in a spiral shape to prevent electric field discharge to the outside of the cable, and the performance of the wire shielding layer may be determined according to the diameter, number, interval, and the like of the wires.

However, when the structure of the offshore wind power submarine cable and the core shown in fig. 1 and2 is considered, there is a possibility that moisture permeated into the core diffuses in the longitudinal direction of the offshore wind power submarine cable through a space between the metal wire constituting the wire shielding layer and the water blocking tape layer or the like.

Accordingly, the inventors have experimentally confirmed that when the water tree size inside the insulating layer 330 measured according to the standard ASTM D6097 satisfies a specific range, it is preferable that the dielectric strength of the submarine cable for offshore wind power is greatly improved when the water tree size satisfies a specific range on the premise that the degree of crosslinking and the degree of crystallinity of the insulating layer 330 are adjusted to the specific range, and completed the present invention.

Specifically, when the water tree size inside the insulating layer 330 measured in accordance with the standard ASTM D6097 is adjusted to 850 μm or less, the dielectric strength of the submarine cable for offshore wind power can be greatly improved. Preferably, when the water tree size is adjusted to 850 μm or less on the premise that the degree of crosslinking of the insulating layer 330 is adjusted to 77% or more and the degree of crystallinity is adjusted to 35% or more, the dielectric strength of the offshore wind power submarine cable may be 80kV/mm or more.

Here, the water tree size is the largest water tree size of the largest dimension among the water trees existing inside the insulating layer 330, and the water tree size represents the length of the longest width in one water tree.

Here, the degree of crosslinking of the insulating layer 330 may be adjusted by adjusting the content of the added crosslinking agent and the process conditions of the crosslinking reaction, and the degree of crystallinity of the insulating layer 330 may be adjusted by the content of crosslinking byproducts or other foreign substances inside the insulating layer 330 and the extrusion/cooling process conditions.

The measurement of the degree of crosslinking of the insulating layer 330 is performed according to the method described in ASTM D2765, and since the insulating layer is made of crosslinked polyethylene, the degree of crosslinking can be confirmed according to the following equation 1, since the filler is not included.

That is, blocks having a vertical length, a lateral length, and a thickness of about 2mm, and 1mm, respectively, were fabricated by thinly cutting the insulating layer 330, and an insulating sample was fabricated by making a plurality of such blocks about 0.3g, and then "total weight of insulating sample" was accurately measured. After that, the insulating sample was surrounded by a net and put into boiling xylene, refluxed by a reflux condenser for 12 hours, then sufficiently dried at 80 ℃, and the remaining insulating sample was extracted, and by measuring the weight of "insulating sample after xylene reflux and drying", it was calculated according to the following equation 1.

Mathematics 1

Crosslinking degree (%) = ("weight of insulating sample after xylene reflow and drying"/"total weight of insulating sample") ×100

In addition, the crystallinity of the insulating layer 330 may be measured by a Differential Scanning Calorimeter (DSC), and may be measured at a temperature rising rate of 10 ℃/min from-20 ℃ to 150 ℃ under a nitrogen atmosphere condition, and a heat of fusion Δh value calculated from a reference point from 20 ℃ to 120 ℃ is calculated according to the following equation 2. In the following formula 2, deltaH _PE represents the heat of fusion of polyethylene, which is 293.6J/g.

Mathematics 2

Further, the method for measuring the water tree size according to the standard ASTM D6097 is as follows: a Crystal Violet (Crystal Violet) 0.1% staining reagent was stirred on a hot plate (hot plate) set at 70 ℃ for one hour to raise the temperature, or 6g of methylene blue (METHYLENE BLUE) and 0.5g of Na ₂CO₃ were put into 200ml of distilled water and stirred on a hot plate (hot plate) set at 70 ℃ for four hours to raise the temperature, then kept at 70 ℃ after one day and put into an insulating layer sample, the insulating layer sample was taken out after staining the insulating layer sample at 70 ℃ for 80 minutes, then washed in distilled water, wiped with ethanol, and then the water tree size inside the insulating layer sample was observed by a microscope.

Examples

Production example

Insulating layer samples (thickness: 150 μm) and cable samples having the crosslinking degree, crystallinity and maximum water tree size described in Table 1 below were produced.

TABLE 1

	Example 1	Example 2	Comparative example 1	Comparative example 2
					Degree of crosslinking (%)	80.1	77.4	71.5	69.4
Crystallinity (%)	36.0	35.1	34.5	33.1
					Maximum water tree size (μm)	830	850	920	1070

Evaluation of physical Properties

1) Evaluation of insulation breakdown Voltage (BDC)

The examples and comparative examples cut 20 insulating layer samples at a size of 5cm×5cm, respectively, and the insulation breakdown voltage was measured while boosting at a rate of 0.5kV/s using a Ramp-up (continuous increase) method using a 0.5inch ball electrode, and after conversion to a thickness, the breakdown electric field (kV/mm) was calculated, and the 63.2% breakdown electric field was calculated using a Weibull distribution.

2) Long term water tree evaluation experiment

The cable sample was immersed in a 3.5% nacl solution according to Regime B test of the standard CIGRE TB722, after which an aging (aging) operation of applying a frequency and voltage specified in the standard was performed during a specified time, after which an ac insulation breakdown voltage test was performed on the cable within 72 hours and pass/fail was confirmed.

Physical property evaluation results are shown in table 2 below.

TABLE 2

	Example 1	Example 2	Comparative example 1	Comparative example 2
					Insulation breakdown voltage (63.2%)	90	84	75	60
Long term water tree evaluation	By passing through	By passing through	Failure of	Failure of

As described in table 2 above, the insulating layer samples of examples 1 and 2 having an internal maximum water tree size of 850 μm or less exhibited excellent insulation breakdown voltage and Regime B test on the premise that the crosslinking degree of the insulating layer was 77% or more and the crystallinity was 35% or more, whereas the insulating layer samples of comparative examples 1 and 2 having no standard in terms of crosslinking degree, crystallinity and maximum water tree size exhibited a significant drop in Regime B test.

While the present invention has been described with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit of the invention as set forth in the appended claims. Accordingly, if a modified embodiment includes the constituent elements of the claims, it should be regarded as belonging to the present invention.

Claims (11)

1. A submarine cable for offshore wind power is characterized in that,

Comprising more than one core which is arranged on the inner side of the shell,

The core comprises a conductor and an insulating layer surrounding the conductor,

The water tree size inside the insulating layer is 850 μm or less as measured according to standard ASTM D6097.

2. The offshore wind power submarine cable according to claim 1, wherein,

The insulating layer has a crosslinking degree of 77% or more and a crystallinity of 35% or more.

3. Submarine cable for offshore wind power according to claim 2, wherein,

The insulating layer comprises a crosslinked polyethylene.

4. A submarine cable for offshore wind power according to any one of claims 1 to 3,

The insulation breakdown voltage of the insulation layer is more than 80 kV/mm.

5. A submarine cable for offshore wind power according to any one of claims 1 to 3,

The core includes a conductor, an inner semiconductive layer surrounding the conductor, an insulating layer surrounding the inner semiconductive layer, an outer semiconductive layer surrounding the insulating layer, a wire shielding layer surrounding the outer semiconductive layer, and a core armor surrounding the wire shielding layer.

6. The offshore wind power submarine cable according to claim 5, wherein,

Further comprises:

An inner water stop tape layer surrounding the outer semiconductive layer between the outer semiconductive layer and the line shield;

An outer water-stop tape layer surrounding the wire shield layer; and

A metal jacket layer surrounding the outer water stop tape layer.

7. The offshore wind power submarine cable according to claim 6, wherein,

The external water-stop tape layer contains one or more selected from the group consisting of powder containing a super absorbent resin, an adhesive tape, a coating layer, and a film.

8. A submarine cable for offshore wind power according to any one of claims 1 to 3,

Comprises a plurality of cores, wherein each core comprises a plurality of cores,

A filler member is provided in a central portion between the cores and an outer core region.

9. The offshore wind power submarine cable according to claim 8, wherein,

The filling member comprises yarns of polypropylene.

10. The offshore wind power submarine cable according to claim 8, wherein,

There is provided a tie layer for ending a plurality of cores and filler members in a circular shape,

And an armor layer which mixes the polypropylene yarns and the asphalt is further arranged on the outer side of the binding tape layer.

11. The offshore wind power submarine cable according to claim 10, wherein,

A metal armor layer is arranged on the outer side of the armor cushion layer,

And an anti-corrosion layer for mixing the polypropylene yarns and the asphalt is further arranged on the outer side of the metal armor layer.