CN211529653U - Oil-filled 500kV ultrahigh-voltage submarine cable - Google Patents

Abstract

The utility model discloses an oil-filled 500kV ultrahigh voltage submarine cable, the conductor supporting tube of the utility model plays a role in supporting a trapezoidal conductor, insulating oil is continuously circulated inside during work, conductor heat is taken away, conductor temperature is reduced, and conductor current-carrying capacity is increased; the double-layer semi-conductive tape wrapping layer can effectively prevent the generation of a bulge-shaped high-voltage discharge phenomenon; the copper strip shielding layer is used for passing capacitance current when the cable is normally electrified and passing short-circuit current when the cable is in short-circuit fault; the electromagnetic field caused when the cable is electrified is shielded in the insulated wire core so as to reduce the electromagnetic interference generated to the outside; the metal shielding layer also plays a role in limiting the influence of an external electromagnetic field on the inside; homogenizing the electric field to prevent axial discharge; the aramid fiber yarn and the cable are concentrically and spirally wound, and compact gaps are small. The asphalt is smeared, the fatigue resistance is over 10 times of that of steel wires, and the asphalt is corrosion-resistant, scratch-resistant, high-temperature and low-temperature resistant, and the service life of the asphalt in seawater is over 30 years.

Description

Oil-filled 500kV ultrahigh-voltage submarine cable

Technical Field

The utility model relates to a submarine power transmission uses the field of cable, especially relates to an oil charge type 500kV superhigh pressure submarine cable.

Background

The submarine cable is a cable laid on the bottom of rivers, lakes and seas, the development history of the submarine cable exceeds one hundred years, the submarine cable is initially used for supplying power to devices such as lighthouses and the like in the offshore, and the submarine cable is mainly used for power grid connection, communication connection, short-distance river crossing and the like between islands and continents or islands, land, offshore wind farms and offshore drilling platforms.

The demand of submarine cables is large, but few manufacturers with high-voltage and ultrahigh-voltage submarine cable production capacity exist in the world at present, so that the submarine cable production system provides wide market prospect for cable manufacturing industry. The submarine cable has complex submarine topography, the working environment of the submarine cable is different from that of an underground cable, and the submarine cable has the technical difficulties of longitudinal water blocking technology of a conductor, development of a flexible connector with the same electrical performance and mechanical performance as a cable body, corrosion prevention and corrosion prevention design of a metal sheath and armor, safety early warning and temperature measurement control of a large-length submarine cable, and routine tests of the large-length submarine cable and the connector.

Cross-linked polyethylene insulated (XLPE) submarine cables developed in the last 80 century, mostly for voltage classes of 220 kV and below, and were far less experienced in manufacture and operation than oil-filled submarine cables, the highest voltage class of XLPE AC submarine cables by far the present time were 420 kV 4 single core submarine cables 2.2 km long, installed by Nixon (NEXANS) corporation for large Ormen Lange gas fields located in Norwegian, 500kV AC long distance submarine cables, the only oil-filled cables currently in use.

Compared with an oil-filled cable, the XLPE cable has the advantages that firstly, the XLPE cable is solid insulation, a complex oil-filled system is not needed, oil level detection and oil pressure control are not needed, operation cost is low, secondly, the XLPE cable is free of a lead sheath, small in bending radius, light in weight, longer in production and laying length, simpler in laying installation and transportation than the oil-filled cable, thirdly, the electrical performance and the mechanical performance of the XLPE submarine cable are superior to those of the oil-filled cable, and accordingly, the development of the XLPE submarine cable has wider prospects, but numerous technical problems need to be solved.

In 2002, the first extrusion type single-core direct current submarine cable (light direct current cable, Edison ABB) has the voltage of +/-150 kV, the length of 40 km and the capacity of 330 MW, and is used for connecting the Long island in New York and Connecticut in the United states. The direct current submarine cable is a unipolar cable extruded by 3 layers of polymer materials, the inner shielding layer and the outer shielding layer are simultaneously extruded with the insulating layer, and the direct current submarine cable has the advantages of high strength, environmental protection, convenience in burying and the like, and is suitable for severe environments such as deep sea and the like.

Related technical problems of submarine cables:

the submarine cable is waterproof, when the cable sheath and insulation are damaged and joints are damaged due to mechanical stress or external force, moisture or water can infiltrate along the longitudinal and radial gaps of the cable, the electrical strength of the insulation is reduced, and therefore most high-voltage submarine cables have longitudinal and radial waterproof measures for preventing water intrusion. The radial measure is to wrap a semi-conductive water-blocking expansion belt outside the insulating shield and the metal shield layer, the metal waterproof layer, namely the metal sheath, is added on the outer surface of the metal shielding layer, the electric field intensity of the medium-voltage cable is relatively low, an aluminum-plastic composite sheath is generally used, only a polymer sheath is used, the high-voltage cable adopts a metal sealing sleeve of lead, aluminum and stainless steel, the polymer sheath has waterproofness, but has a certain water absorption rate because the structure of the water-absorbing material is mainly a semi-crystalline polymer consisting of a crystalline phase and an amorphous phase, the crystalline phase has a compact structure, the molecules in the amorphous phase are arranged loosely, and large gaps exist among the molecules, under the action of an alternating electric field, polar water molecules are continuously turned over back and forth, the water-resistant agent with water absorption function is added in the sheath when the polymer sheath is adopted.

The longitudinal water blocking adopts water blocking powder with good filling effect, the water absorption capacity of the water blocking powder is dozens or even thousands of times of that of the water blocking powder, the water blocking powder has high water absorption strength and high expansion rate, and the water blocking powder can rapidly expand to form a gel substance after absorbing water to block a water seepage channel and stop further diffusion and extension of water and moisture, so that the length of the damp cable is reduced to the minimum.

The flexible joint is the same as the cable body, not only the electrical performance of the cable needs to be ensured, but also mechanical stress such as tension, torsion, bending and the like needs to be borne, the technical difficulty is large, the requirements on production and installation environments are strict, and only a few well-known manufacturers in the world of the ultrahigh-voltage submarine cable flexible joint can produce the cable.

The method is characterized in that conductor connection is firstly carried out in a factory, silver welding and other-diameter wire core welding are adopted, welding defects such as unconnected connection, cracks, micropores and the like are avoided during welding, welding quality can be checked by X rays, and conductors close to a welding position are weak links due to calcination, and the mechanical strength of the conductors is only about 70% of that of normal conductors. Secondly, insulation is connected, reaction force cones are manufactured at two ends of a cable to be connected, then an insulating paper tape or a polymer insulating tape similar to a cable body is wound, or an extrusion molding die casting method is adopted, XLPE is directly extruded into a forming die by an extruding machine, in order to avoid the phenomenon that the thickness of one-time extrusion is too large (15-30 mm), so that large air holes are generated in the later pressurizing and heating vulcanization process, the layered extrusion molding vulcanization treatment can be changed, and the processing period is long and can reach more than 1 month. The sheath is formed by welding a lead pipe which is sheathed outside the insulation in advance and is armored together with the cable body, so that the flexible joint is a hidden cable joint which is difficult to identify in appearance unless specially marked.

3 the anti-corrosion and anti-corrosion design of the metal sheath and the armor, the service life of the submarine cable depends on the anti-corrosion service life of the steel wire armor to some extent, so a special steel wire-zinc-aluminum magnesium alloy coating steel wire armor needs to be adopted. The outer sheath made of medium and high density polyethylene can overcome the defects of easy abrasion, easy falling and the like of asphalt and can form better protection for steel wire armor. The steel wire armor is additionally provided with a polypropylene rope outer tegument layer, so that the seawater erosion resistance and the construction abrasion resistance of the cable can be improved.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the purpose is exactly in order to remedy prior art's defect, provides an oil charge type 500kV superhigh pressure submarine cable.

The utility model discloses a realize through following technical scheme:

the utility model provides an oil charge type 500kV superhigh pressure submarine cable, including insulating oil circulation passageway, the conductor stay tube, trapezoidal copper conductor, the semi-conductive area is around covering one, semi-conductive conductor shielding layer, the crosslinked polyethylene insulating layer, insulating semi-conductive shielding layer, the semi-conductive area is around covering two, copper tape shielding layer, copper wire weaving layer one, bed course one, the lead alloy protective sheath, copper wire weaving layer two, copper alloy area enhancement layer, bed course two, polyethylene anticorrosion restrictive coating, copper alloy area moth-proofing layer, bed course three, flat copper strip armor, the mixed oversheath of high strength fibre stick pitch is constituteed.

The conductor supporting tube is an empty tube with an aluminum alloy interlocking binding line, plays a role in supporting the trapezoidal conductor, and insulating oil continuously circulates in the conductor supporting tube during working to take away heat of the conductor, reduce the temperature of the conductor and increase the current-carrying capacity of the conductor.

The trapezoidal copper conductor is formed by stranding a plurality of trapezoidal copper wires in a layered mode, each layer of copper wires is drawn and pressed, the gap is reduced, and compared with a round monofilament conductor, the trapezoidal copper conductor is 8% -10% smaller in outer diameter of a conductor with the same cross section due to the adoption of the structure in the shape, so that the outer diameter of the whole cable is smaller. When the cable works, the gaps of the conductors are filled with insulating oil, so that air gaps in the conductors can be eliminated, and the action of water vapor in the air is avoided. When the insulating oil pump works, heat of the conductor is taken away along with the circulation of the insulating oil, and current carrying is increased.

The semi-conductive tape wrapping layer I is a semi-conductive cloth tape wrapped on the trapezoidal conductor. Prevent the extruded semi-conductive shielding layer from being embedded into the trapezoidal conductor layer to generate the protrusion-shaped high-voltage discharge phenomenon.

The semi-conductive conductor shielding layer is a semi-conductive polyethylene shielding material extruded on the semi-conductive tape wrapping layer, plays a role in balancing an electric field and prevents a high-voltage discharge phenomenon.

The cross-linked polyethylene insulating layer is a cross-linked polyethylene insulating material extruded outside the shielding layer of the semi-conductive conductor, and the adopted material is a high-purity cross-linked polyethylene insulating material which has the function of isolating current from the outer protective layer.

The insulating semi-conductive shielding layer is a semi-conductive polyethylene shielding material extruded on the crosslinked polyethylene insulating layer, and plays a role in balancing an electric field and preventing a high-voltage discharge phenomenon. The semi-conductive layer and the cross-linked polyethylene insulation and conductor semi-conductive shielding layer are extruded together through a vertical tower type cross-linked production line, contact surfaces are close and seamless, and the phenomenon of high-voltage discharge caused by gaps is prevented.

And the second semi-conductive belt wrapping layer is a semi-conductive cloth belt wrapped on the crosslinked polyethylene insulating layer, so that the copper belt metal shield is prevented from being pressed to damage the insulating layer.

And the copper strip shielding layer is formed by wrapping a copper strip on the second semi-conductive strip wrapping layer. When the cable is normally electrified, the metal shielding layer passes through capacitance current, and short-circuit current passes through the metal shielding layer when short-circuit fault occurs; the electromagnetic field caused when the cable is electrified is shielded in the insulated wire core so as to reduce the electromagnetic interference generated to the outside; the metal shielding layer also plays a role in limiting the influence of an external electromagnetic field on the inside; the electric field is homogenized to prevent axial discharge.

The first copper wire braided layer is a copper wire mesh braided on the copper strip shield by a plurality of strands of copper wires through a metal braiding machine, plays a role in increasing the cross section of the copper strip shield layer, and has the same partial function as the copper strip shield layer.

The first cushion layer is wrapped on the first copper wire braid layer through a plurality of layers of insulating cloth tapes to play a role in isolation.

The lead alloy protective sleeve is a compact metal protective sleeve layer formed by extruding lead alloy, and the lead alloy has excellent corrosion resistance and waterproof performance, so that the internal action of the cable is well protected.

The copper wire braided layer II is a copper wire mesh braided on the copper strip shield by a plurality of strands of copper wires through a metal braiding machine, and when the cable is normally electrified, the metal shielding layer passes through capacitance current; the electromagnetic field caused when the cable is electrified is shielded in the insulated wire core so as to reduce the electromagnetic interference generated to the outside; the metal shielding layer also plays a role in limiting the influence of an external electromagnetic field on the inside; the electric field is homogenized to prevent axial discharge.

The copper alloy reinforcing layer is formed by lapping a copper alloy belt on a copper wire braided layer in an overlapping mode, the copper wire braided layer is protected, and the mechanical strength of the cable is enhanced.

And the second cushion layer is wrapped on the copper alloy belt reinforcing layer by a plurality of layers of insulating cloth belts to play a role in isolation.

The polyethylene anticorrosion sheath layer is a sheath layer extruded by high-density polyethylene, and the high-density polyethylene has waterproof and anticorrosion performances and can well prevent seawater from corroding the cable core.

The copper alloy belt mothproof layer is formed by lapping and wrapping copper alloy belts on a polyethylene anticorrosive sheath layer in an overlapping mode, and prevents small and medium-sized seawater animals from biting the cable and damaging the internal structure of the cable.

And the third cushion layer is formed by wrapping a plurality of layers of insulating cloth belts on the reinforcing layer of the copper alloy belt in a wrapping manner, so that an isolation effect is achieved.

The flat copper strip armor layer is formed by winding a plurality of flat copper strips on a cable, plays the roles of tensile and compression resistance and protects a cable core.

The high-strength fiber rod and asphalt mixed outer sheath is formed by winding a fiber rod consisting of aramid fiber yarns on a cable and smearing asphalt on the cable.

The utility model has the advantages that: the conductor supporting tube of the utility model plays a role of supporting the trapezoidal conductor, and the insulating oil is continuously circulated inside during work, thereby taking away the heat of the conductor, reducing the temperature of the conductor and increasing the current-carrying capacity of the conductor; the double-layer semi-conductive tape wrapping layer can effectively prevent the generation of a bulge-shaped high-voltage discharge phenomenon; the copper strip shielding layer is used for passing capacitance current when the cable is normally electrified and passing short-circuit current when the cable is in short-circuit fault; the electromagnetic field caused when the cable is electrified is shielded in the insulated wire core so as to reduce the electromagnetic interference generated to the outside; the metal shielding layer also plays a role in limiting the influence of an external electromagnetic field on the inside; homogenizing the electric field to prevent axial discharge; the aramid fiber yarn and the cable are concentrically and spirally wound, and compact gaps are small. The asphalt is smeared, the fatigue resistance is over 10 times of that of steel wires, and the asphalt is corrosion-resistant, scratch-resistant, high-temperature and low-temperature resistant, and the service life of the asphalt in seawater is over 30 years.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Detailed Description

As shown in fig. 1, an oil-filled 500kV ultrahigh voltage submarine cable comprises an insulating oil circulation channel 1, a conductor support tube 2, a trapezoidal copper conductor 3, a first semiconductive tape wrapping layer 4, a semiconductive conductor shielding layer 5, a crosslinked polyethylene insulating layer 6, an insulating semiconductive shielding layer 7, a second semiconductive tape wrapping layer 8, a copper tape shielding layer 9, a first copper wire braided layer 10, a first cushion layer 11, a lead alloy protective sleeve 12, a second copper wire braided layer 13, a copper alloy tape reinforcing layer 14, a second cushion layer 15, a polyethylene anticorrosion sheath layer 16, a copper alloy tape mothproof layer 17, a third cushion layer 18, a flat copper tape armor layer 19 and a high-strength fiber rod and asphalt mixed outer sheath 20.

Conductor support tube 2 is the empty pipe of aluminium alloy area interlocking bundle line, plays the effect of supporting trapezoidal conductor, and the during operation insulating oil is circulated in the inside constantly, takes away the conductor heat, reduces the conductor temperature, increases the conductor current-carrying capacity. The aluminum alloy belt is made of 8000 series rare earth aluminum alloy strips, the edges and the edges are locked and then are banded through an interlocking armoring machine, and the supporting pipe can be prevented from being flattened during traction through a specially manufactured core-penetrating crawler tractor and then is coiled into a vertical wire falling and winding frame for later use.

Trapezoidal copper conductor 3 is twisted by many copper wires layering that the monofilament shape is trapezoidal, adopts every layer to draw to sticis, reduces the technology in gap, adopts this kind of shape structure compared in circular monofilament conductor, and the conductor sticiss the coefficient to reach 98%, and with section conductor external diameter will be less 8% ~10%, make whole cable external diameter less. Drawing the monofilament into trapezoidal monofilament with special mold, and twisting with nanometer alloy drawing mold to form round and smooth drawn conductor without crack and with cross section of 1000mm²The copper conductor of (1). The cable is connected into the transmission and distribution network system and is connected into the oil-filled circulating system, and when the cable is electrified, the gaps of the conductors are filled with insulating oil, so that air gaps in the conductors can be eliminated, and the action of water and gas in the air gaps is avoided. When the insulating oil pump works, heat generated by the conductor is taken away along with the circulation of the insulating oil, and the current-carrying capacity is increased. The design is a combined cable formed by combining all the advantages of the oil-filled paper insulated cable and the ultra-high voltage of the cross-linked polyethylene insulated cable.

And the semi-conductive tape wrapping layer I4 is a semi-conductive cloth tape wrapped on the trapezoidal conductor. Prevent the extruded semi-conductive shielding layer from being embedded into the trapezoidal conductor layer to generate the protrusion-shaped high-voltage discharge phenomenon. The cloth belt has high mechanical strength and small resistivity, is firmly attached to the semi-conductive shielding layer after being extruded, and cannot generate gaps to influence the electrical property.

The semi-conductive conductor shielding layer 5 is a semi-conductive polyethylene shielding material extruded on the semi-conductive belt, plays a role in balancing an electric field and prevents a high-voltage discharge phenomenon. The semi-conducting layer and the crosslinked polyethylene insulating layer are extruded together through a vertical tower type crosslinking production line, the contact surfaces are close and seamless, and the phenomenon of high-voltage discharge caused by the clearance is prevented.

The crosslinked polyethylene insulating layer 6 is a crosslinked polyethylene insulating material extruded outside the shielding layer of the semiconductor conductor, and the adopted material is a high-purity crosslinked polyethylene insulating material which has the function of isolating current from the outer protective layer. As the ultra-clean crosslinked polyethylene insulating material is adopted, the average value of the breakdown strength reaches 135kV/mm and exceeds the average breakdown strength 80kV/mm in the same period, the designed insulation thickness is reduced by 28mm from 32mm, and the outer diameter of the cable is reduced.

The insulating semi-conductive shielding layer 7 is a semi-conductive polyethylene shielding material extruded on the crosslinked polyethylene insulating layer, plays a role in balancing an electric field and prevents a high-voltage discharge phenomenon. The semi-conductive layer and the cross-linked polyethylene insulation and conductor semi-conductive shielding layer are extruded together through a vertical tower type cross-linked production line, contact surfaces are close and seamless, and the phenomenon of high-voltage discharge caused by gaps is prevented.

And the second semi-conductive belt wrapping layer 8 is a semi-conductive cloth belt wrapped on the crosslinked polyethylene insulating layer, so that the copper belt metal shield is prevented from being pressed to damage the insulating layer.

The copper strip shielding layer 9 is formed by wrapping a copper strip on a semi-conductive strip. When the cable is normally electrified, the metal shielding layer passes through capacitance current, and short-circuit current passes through the metal shielding layer when short-circuit fault occurs; the electromagnetic field caused when the cable is electrified is shielded in the insulated wire core so as to reduce the electromagnetic interference generated to the outside; the metal shielding layer also plays a role in limiting the influence of an external electromagnetic field on the inside; the electric field is homogenized to prevent axial discharge.

The copper wire braided layer I10 is a copper wire mesh braided on the copper strip shield by a plurality of strands of copper wires through a metal braiding machine, plays a role in increasing the cross section of the copper strip shield layer, and has the same partial function as the copper strip shield layer. The braided copper wire mesh is formed by weaving copper wire strands on the copper tape shielding layer in a crossing manner in opposite directions for the positive and negative groups of wires. The overall cross section is determined by the cable short-circuit current. If the cable or the equipment has faults, the flow guide effect is achieved.

The first cushion layer 11 is wrapped on a copper wire braid layer through a plurality of layers of insulating cloth tapes and plays a role in isolation.

The lead alloy protective sleeve 12 is a compact metal sheath layer formed by extruding lead alloy, and the lead alloy has excellent corrosion resistance and waterproof performance, so that the internal action of the cable is well protected. And extruding and wrapping the lead alloy on the cable core through a metal protective layer extruding machine to form a compact lead alloy protective layer. The layer is an important waterproof and anticorrosive layer of the submarine ultrahigh-voltage cable, is seamlessly detected by a metal flaw detector in the extrusion process, and is drawn and compressed after being repaired if the defect is detected.

The copper wire braided layer II 13 is a copper wire mesh braided on the copper strip shield by a plurality of strands of copper wires through a metal braiding machine, and when the cable is normally electrified, the metal shielding layer passes through capacitance current; the electromagnetic field caused when the cable is electrified is shielded in the insulated wire core so as to reduce the electromagnetic interference generated to the outside; the metal shielding layer also plays a role in limiting the influence of an external electromagnetic field on the inside; the electric field is homogenized to prevent axial discharge.

The copper alloy belt reinforcing layer 14 is formed by lapping and covering a copper alloy belt on a copper wire braided layer in an overlapping mode, so that the copper wire braided layer is protected, and the mechanical strength of the cable is enhanced.

And the second cushion layer 15 is formed by wrapping a plurality of layers of insulating cloth belts on the reinforcing layer of the copper alloy belt in a wrapping manner, and plays a role in isolation.

The polyethylene anticorrosion sheath layer 16 is a sheath layer extruded by high-density polyethylene, and the high-density polyethylene has waterproof and anticorrosion performances and can well prevent seawater from corroding the cable core.

The copper alloy belt mothproof layer 17 is formed by lapping and wrapping copper alloy belts on the polyethylene anticorrosive sheath layer in an overlapping mode, and prevents small and medium-sized seawater animals from biting the cable and damaging the internal structure of the cable. The layer adopts double-layer wrapping, each layer of the wrapping is wound on the anti-corrosion sheath in an overlapping mode, and the overlapping rate is not less than 30%. The lap joint is continuously coated with adhesive during production, so that gaps of the copper strips are blocked, and marine micro organisms are prevented from invading the cable to bite the protective layer.

And the third cushion layer 18 is formed by wrapping a plurality of layers of insulating cloth belts on the reinforcing layer of the copper alloy belt in a wrapping manner, and plays a role in isolation.

The flat copper strip armor layer 19 is formed by winding a plurality of flat copper strips on a cable, plays the roles of tensile and compression resistance and protects a cable core. The winding layer is compact, and the maximum gap is not more than 0.2mm

The high-strength fiber rod and asphalt mixed outer sheath 20 is formed by winding a fiber rod consisting of aramid fiber yarns on a cable and smearing asphalt on the cable. The aramid fiber rod and the cable are concentrically and spirally wound, and compact gaps are small. The asphalt is smeared, the fatigue resistance is over 10 times of that of steel wires, and the asphalt is corrosion-resistant, scratch-resistant, high-temperature and low-temperature resistant, and the service life of the asphalt in seawater is over 30 years.

The product has the following process flow: interlocking support pipe banding, twisting a conductor, wrapping a semi-conductive belt, three-layer co-extrusion (conductor semi-conductive shielding, crosslinked polyethylene insulation and insulated semi-conductive shielding), wrapping the semi-conductive belt and the copper belt shielding, weaving a copper wire shielding, wrapping a cushion layer, extruding a lead alloy sheath, drawing and tightly pressing the lead alloy sheath, weaving the copper wire shielding layer, wrapping a copper alloy reinforced layer, wrapping the cushion layer, extruding a polyethylene sheath, wrapping the cushion layer, winding a copper alloy armor, winding an aramid fiber rod and coating asphalt.

Claims (10)

1. The utility model provides an oil charge type 500kV superhigh pressure submarine cable which characterized in that: the cable comprises a conductor supporting tube, a trapezoidal copper conductor, a semi-conductive belt wrapping layer I, a semi-conductive conductor shielding layer, a cross-linked polyethylene insulating layer, an insulating semi-conductive shielding layer, a semi-conductive belt wrapping layer II, a copper strip shielding layer, a copper wire braid layer I, a cushion layer I, a lead alloy protective sleeve, a copper wire braid layer II, a copper alloy belt reinforcing layer, a cushion layer II, a polyethylene anticorrosive sheath layer, a copper alloy belt mothproof layer, a cushion layer III, a flat copper strip armor layer and a high-strength fiber rod asphalt mixed outer sheath in sequence from inside to outside, wherein the conductor supporting tube is hollow, and an inner cavity of the conductor supporting tube is an insulating oil circulation channel.

2. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the conductor supporting tube is a hollow tube with an aluminum alloy interlocking binding line; the trapezoidal copper conductor is formed by twisting a plurality of trapezoidal copper wires in a layered mode, and each layer of copper wires is drawn and compacted.

3. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the semi-conductive belt wrapping layer I and the semi-conductive wrapping layer II are respectively semi-conductive cloth belts wrapped on the trapezoidal copper conductor and the insulating semi-conductive shielding layer.

4. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the semiconductive conductor shielding layer and the insulating semiconductive shielding layer are semiconductive polyethylene shielding materials extruded on the semiconductive belt wrapping layer I and the crosslinked polyethylene insulating layer respectively.

5. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the first copper wire braided layer and the second copper wire braided layer are both copper wire meshes formed by braiding a plurality of strands of copper wires through a metal braiding machine.

6. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the first cushion layer, the second cushion layer and the third cushion layer are all wrapped layers by multiple layers of insulating cloth belts.

7. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the lead alloy protective sleeve is a protective sleeve layer formed by extruding lead alloy; the copper alloy belt reinforcing layer and the copper alloy belt mothproof layer are formed by lapping and covering copper alloy belts in an overlapping mode.

8. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the polyethylene anticorrosion sheath layer is formed by extruding and wrapping high-density polyethylene.

9. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the flat copper strip armor layer is formed by winding a plurality of flat copper strips on the cushion layer III.

10. The oil-filled 500kV extra-high voltage submarine cable according to claim 1, wherein: the high-strength fiber rod and asphalt mixed outer sheath is formed by winding a fiber rod consisting of aramid fiber yarns on the flat copper strip armor layer.

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