Submarine power cable suitable for simultaneous pipe penetration of multiple cables and laying mode thereof

Abstract

The invention relates to the technical field of submarine cable laying, in particular to a submarine power cable suitable for simultaneous pipe penetration of multiple cables and a laying mode of the submarine power cable. A semi-conductive water-blocking binding tape, an inner shield, an insulator, an insulation shield, a semi-conductive water-blocking tape, a metal sheath, an inner sheath, a filling strip, an optical unit, a water-blocking tape, an inner lining layer, an armor layer and an outer coating layer are sequentially arranged on the outer side of the water-blocking conductor. According to the submarine power cable and the laying mode thereof, the hollow metal sheath structure is adopted, and the insulating cooling oil is introduced into the middle, so that the operating temperature of the cable can be reduced, and the current-carrying capacity is greatly improved; the filling strip and the optical unit are made of semi-conductive materials, so that induced current generated at the optical unit in the operation process of the submarine cable can be led out, and generation of an electromagnetic field is reduced; and the armoring material adopts non-magnetic armoring, so that the carrying capacity of the system can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of submarine cable laying, in particular to a submarine power cable suitable for multiple submarine power cables to be used through pipes at the same time and a laying method thereof. Background Art

[0002] Submarine cables play a vital role in the field of offshore wind power. As an important renewable energy source, the development of offshore wind power relies on efficient and stable submarine cables for power transmission. Submarine cables must not only meet basic electrical performance, but also have excellent water resistance, mechanical properties and corrosion resistance. With the advancement of global carbon neutrality goals, the scale of offshore wind power installations continues to expand, and the demand for submarine cables is also growing. The submarine cable industry is constantly innovating technology and improving product quality to meet the needs of large-scale, long-distance transmission of offshore wind power and promote the green transformation of the global energy structure.

[0003] When laying submarine cables, if the route passes through aquaculture areas, in order to reduce the construction area and save land costs, it is considered to lay multiple submarine cables in one pipeline at the same time. Traditional submarine cables use conventional optical fiber composite submarine cables. When multiple traditional AC submarine cables are running at the same time, a large induced current will be generated, forming an electromagnetic field. At the same time, the simultaneous operation of multiple cables will affect heat dissipation, thus causing a large amount of loss and reducing the system current carrying capacity. Summary of the invention

[0004] The technical problem to be solved by the present invention is that when multiple AC submarine cables are running at the same time, a large electromagnetic field will be generated, which will also affect heat dissipation, cause a large amount of loss, and reduce the current carrying capacity of the system.

[0005] The technical solution adopted by the present invention to solve its technical problem is: a submarine power cable, including a water-blocking conductor, on the outside of which are sequentially provided with a semi-conductive water-blocking binding tape, an inner shield, insulation, an insulating shield, a semi-conductive water-blocking tape, a metal sheath, an inner sheath, a filling strip, an optical unit, a water-blocking tape, an inner lining layer, an armor layer and an outer sheath.

[0006] The water-blocking conductor adopts a profiled water-blocking conductor structure, a compression coefficient of ≥98%, and adopts a longitudinally wrapped water-blocking tape for water-blocking treatment.

[0007] The insulation is made of high-purity XLPE insulation, and a small amount of heat-resistant material is added to the insulation base to increase the maximum operating temperature of the insulation to 105°C.

[0008] The metal sheath is made of lead alloy or aluminum alloy and has a hollow structure, into which insulating oil is injected for forced liquid cooling.

[0009] The inner sheath is made of semi-conductive material.

[0010] The filling strip is made of semi-conductive material and is in direct contact with the optical unit to lead out the induced current generated in the optical unit.

[0011] The armor layer is made of non-magnetic and high-strength material and will not generate additional induced current in an AC magnetic field environment.

[0012] A laying method suitable for simultaneously threading multiple submarine power cables through pipes, firstly pulling a pipe through a seabed borehole and placing it into a metal pipe, then simultaneously laying multiple power cables in claims 1-7 into the metal pipe, and providing a laying clamp for fixing the power cables at intervals inside the metal pipe, and performing the threading operation by pulling the power cables during laying, and after the submarine cable is laid, sealing the landing end, connecting an external water pump, and passing circulating seawater into the metal pipe to cool the submarine cable, and at the same time, direct contact between the seawater and the submarine cable can realize grounding of the submarine cable.

[0013] The outer side of the laying fixture is provided with a pulley for reducing internal friction, the interior of the laying fixture is provided with a plurality of cable through holes, and the outer side surface of the laying fixture is provided with lateral grooves located outside the cable through holes.

[0014] The laying fixture is made of corrosion-resistant metal and is in close contact with the metal pipe wall.

[0015] The beneficial effects of the present invention are: (1) A submarine power cable suitable for multiple simultaneous pipe-through use and its laying method adopts a hollow metal sheath structure, and insulating cooling oil is passed through the middle, which can reduce the operating temperature of the cable and greatly increase the current carrying capacity; (2) The filling strips and optical units are made of semi-conductive materials, which can conduct the induced current generated at the optical unit during the operation of the submarine cable and reduce the generation of electromagnetic fields; (3) The armor material uses non-magnetic armor, which can increase the current carrying capacity of the system; (4) By laying fixtures to install and support multiple cables at the same time, it can not only improve the continuity between different cables and reduce the heat impact between them, but also improve the internal support and overall safety; (5) Installing rollers on the outside of the laying fixture can greatly reduce the friction of the contact surface and effectively protect the cable; (6) The entire equipment has a compact structure and is more suitable for laying in narrow environments; (7) An external water pump design is used to transport circulating seawater into the pipe, effectively cooling the internal submarine cable. At the same time, direct contact with seawater is used to achieve grounding, thereby improving safety. (8) Slots are opened on the outside of the laying fixture to effectively reduce consumables and weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0017] Figure 1 It is a cross-sectional view of the power cable in the present invention.

[0018] Figure 2 It is a cross-sectional view of the assembly end of the laying fixture in the present invention.

[0019] Figure 3 It is a structural schematic diagram of the laying fixture assembly section in the present invention.

[0020] Figure 4 It is a pipe-threading construction process diagram in the present invention. DETAILED DESCRIPTION

[0021] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] Figure 1 , Figure 2 and Figure 3 A submarine power cable shown includes a water-blocking conductor 1, on the outside of which are sequentially provided a semi-conductive water-blocking binding tape 2, an inner shield 3, an insulation 4, an insulating shield 5, a semi-conductive water-blocking tape 6, a metal sheath 7, an inner sheath 8, a filling strip 9, an optical unit 10, a water-blocking tape 11, an inner lining layer 12, an armor layer 13, and an outer sheath 14.

[0024] The water-blocking conductor 1 adopts a profiled water-blocking conductor structure, with a compression coefficient of ≥98%. During production, each layer is longitudinally wrapped with a water-blocking tape or filled with a water-blocking glue for water-blocking treatment.

[0025] Insulation 4 is made of high-purity XLPE insulation. A small amount of nano-alumina and silicone additives are added during the extrusion production of Insulation 4. Stir and mix thoroughly before adding, which can increase the maximum operating temperature of the insulation to 105°C.

[0026] The metal sheath 7 is made of lead alloy or aluminum alloy and has a hollow structure, into which insulating oil is injected for forced liquid cooling. The lead-plastic extrusion die and die head are modified, and welding lines are added to achieve extrusion of the hollow metal sheath. During the operation of the submarine cable, a circulation system is added at both ends of the submarine cable. The function of the circulation system is to inject circulating insulating oil into the hollow of the metal sheath 7 for circulating cooling and to remove the operating heat.

[0027] The inner sheath 8 is made of semi-conductive material and contacts the filling strip 9. The filling strip 9 and the sheath of the optical unit 10 are made of semi-conductive material. When the semi-conductive filling strip 9 contacts seawater, it can effectively conduct the induced current generated by the cable core and the optical unit 10.

[0028] The filling strip 9 is made of a semi-conductive material and is in direct contact with the optical unit 10 to lead out the induced current generated in the optical unit 10 .

[0029] The armor layer 13 is made of non-magnetic and high-strength material, such as non-magnetic steel wire or other non-magnetic materials of equal strength. In an AC magnetic field environment, no additional induced current will be generated. At the same time, the high-strength material can also protect the cable.

[0030] The outer layer 14 is wrapped with PP rope and anti-corrosion treated by applying asphalt, so it can be used in seawater environment for a long time. A laying method suitable for simultaneously threading multiple submarine power cables through pipes, firstly, pulling a pipe through a seabed borehole and placing it into a metal pipe 15, then simultaneously laying multiple power cables in claims 1-7 into the metal pipe 15, a laying clamp 16 for fixing the power cables is provided at intervals inside the metal pipe 15, and the threading operation is performed by pulling the power cables during laying. After the submarine cable is laid, the landing end is sealed, and an external water pump is connected. By passing circulating seawater into the metal pipe 15, the submarine cable is cooled, and at the same time, the direct contact between the seawater and the submarine cable can realize the grounding of the submarine cable.

[0031] A pulley 17 for reducing internal friction is disposed on the outside of the laying fixture 16 , three cable through holes 18 are provided inside the laying fixture 16 , and a lateral slot 19 is provided on the outer side of the laying fixture 16 outside the cable through holes 18 .

[0032] The laying fixture 16 is made of corrosion-resistant metal and is in close contact with the wall of the metal pipe 15 .

[0033] Construction technology: Under the operating conditions described in this article, multiple submarine cables need to be laid through pipes at the same time, so the following procedures are required: Figure 4 The drilling and pipe pulling operation shown; 1. Measure the route length, calculate the drilling length and the required length of the cable; 2. The site should be repaired and fences and access control should be set up before the equipment enters the site. After completion, the equipment can enter the site; 3. Equipment is placed in the fixed area, drilling rigs and other equipment are installed and debugged, and mud pools are built at the same time; 4. Start drilling the pilot hole, and after completing the pilot hole, perform pre-hole expansion and hole washing. After completing the hole expansion, start drilling the construction hole and recover the mud at the same time; 5. Place the metal tube 15 into the hole, weld each section, and complete the overall tube drawing; 6. Fix the cable on the towing fixture and pull the cable body to pull the pipeline back; 7. After the laying is completed, the landing port of the metal pipe 15 is closed, an external water pump is connected, and circulating water is introduced into the metal pipe 15; 8. Strip the metal sheath 7 from the submarine cables at both ends, connect the hollow position of the metal sheath 7 to the insulating cooling oil injection device, and introduce insulating oil.

[0034] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A submarine power cable, comprising a water-blocking conductor (1), characterized in that: The outer side of the water-blocking conductor (1) is provided with a semi-conductive water-blocking binding tape (2), an inner shield (3), insulation (4), an insulating shield (5), a semi-conductive water-blocking tape (6), a metal sheath (7), an inner sheath (8), a filling strip (9), an optical unit (10), a water-blocking tape (11), an inner lining layer (12), an armor layer (13) and an outer sheath (14) in sequence.

2. A submarine power cable according to claim 1, characterized in that: The water-blocking conductor (1) adopts a profiled water-blocking conductor structure, has a compression coefficient of ≥98%, and adopts a longitudinally wrapped water-blocking tape for water-blocking treatment.

3. A submarine power cable according to claim 1, characterized in that: The insulation (4) is made of high-purity XLPE insulation. When the insulation (4) is extruded, a small amount of heat-resistant material is added to increase the maximum operating temperature of the insulation (4) to 105°C.

4. A submarine power cable according to claim 1, characterized in that: The metal sheath (7) is made of lead alloy or aluminum alloy and has a hollow structure into which insulating oil is injected for forced liquid cooling.

5. A submarine power cable according to claim 1, characterized in that: The inner sheath (8) is made of semi-conductive material.

6. A submarine power cable according to claim 1, characterized in that: The filling strip (9) is made of a semi-conductive material and is in direct contact with the light unit (10) to lead out the induced current generated in the light unit (10).

7. A submarine power cable according to claim 1, characterized in that: The armor layer (13) is made of non-magnetic and high-strength material and will not generate additional induced current in an AC magnetic field environment.

8. A method for laying multiple submarine power cables through pipes at the same time, characterized by: First, a pipe is pulled through a seabed borehole and placed into a metal pipe (15). Multiple power cables in claims 1 to 7 are simultaneously laid into the metal pipe (15). A laying clamp (16) for fixing the power cables is provided at intervals inside the metal pipe (15). During laying, the pipe threading operation is performed by pulling the power cables. After the laying of the submarine cable is completed, the landing end is sealed and connected to an external water pump. Circulating seawater is introduced into the metal pipe (15) to cool the submarine cable. At the same time, direct contact between the seawater and the submarine cable can realize grounding of the submarine cable.

9. A method for laying multiple submarine power cables through pipes at the same time according to claim 8, characterized in that: The outer side of the laying fixture (16) is provided with a pulley (17) for reducing internal friction, the interior of the laying fixture (16) is provided with a plurality of cable through-holes (18), and the outer side surface of the laying fixture (16) is provided with a lateral slot (19) outside the cable through-holes (18).

10. The method for laying multiple submarine power cables through pipes at the same time according to claim 8, characterized in that: The laying fixture (16) is made of corrosion-resistant metal and is in close contact with the wall of the metal pipe (15).

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