Patent Description:
A single core submarine cable transmitting and distributing electric energy through a single conductor is convenient for line connection and equipment connection. Such cable can be used undersea, for supplying electrical power to coastal cities and transmitting power generated by offshore wind power. The reset route of a submarine cable is designed in multiple sections and is complex, the local undersea environment and working conditions will affect the carrying capacity of the cable. There are bottleneck sections in the reset route where the carrying capacity cannot meet the current requirements for which it is rated. As a result, one submarine cable cannot guarantee that every section of a route meets the requirement of current rating.

Reducing electrical loss through armor is an effective way to improve the carrying capacity of a submarine cable. Common types of armor includes galvanized steel wire and copper wire, the galvanized steel wire armor has high resistance, large loss through armor, and low carrying capacity. Copper wire armor has low resistance and high corrosion resistance, but has mechanical strength lower than the galvanized steel wire armor, and is expensive.

<CIT> discloses a submarine cable a single core submarine power cable which includes a wire core, a shielding layer, an insulating layer, an insulator shielding layer, a lead sleeve, an inner protective layer, an armor layer, and an outer protective layer arranged from the inside to the outside. The armor layer is formed by twisting a plurality of metal wires. The armor is divided into a first armor layer for land and a second armor layer for underwater, an end of the first armor layer is butted with an end of the second armor layer to form an integrated armor layer.

<CIT> discloses a submarine optical cable which uses a fiber reinforced material and a galvanized steel wire material to form an armor layer. By adjusting a combination ratio of the fiber reinforced material and galvanized steel wire material, a weight of the submarine optical cable is adjustable.

The present disclosure provides a single core submarine cable having the characteristics of adjustable carrying capacity, low loss through armor, high mechanical strength, and corrosion resistance.

In relation to the constant sum of number, an increase in the number of the first metal wires, reduces the resistance of the armor, the loss through armor is reduced, and the carrying capacity is increased, so the carrying capacity of the cable in the bottleneck section will be sufficient to meet the requirements of rated currents. In relation to the current rating, an increase of the number of the second metal wires improves the mechanical strength, and the cost is reduced. The carrying capacity of the single core submarine cable of the present disclosure can be controlled and adjusted, and meet the requirements of rated currents in the bottleneck section route. Each single core submarine cable can meet the requirements of the rated current in multi-section routes located in different areas and environments, and mechanical strength and cost are optimized. The single core submarine cable is very maneuverable, and construction is convenient. The amount of material used for the single core submarine cable is not significantly extra.

Implementations of the present technology will now be described, by way of example only, with reference to the attached figures.

In the attached figures, single core submarine cable is labeled <NUM>, cable core is labeled <NUM>, inner protecting layer is labeled <NUM>, armor layer is labeled <NUM>, first metal wire is labeled <NUM>, second metal wire is labeled <NUM>, outer protecting layer is labeled <NUM>, conductor shielding layer is labeled <NUM>, insulation layer is labeled <NUM>, insulation shielding layer is labeled <NUM>, first protective layer is labeled <NUM>, water-resistant tape winding layer is labeled <NUM>, metal protective layer is labeled <NUM>, polyethylene protective layer is labeled <NUM>, lining layer is labeled <NUM>, filling protective layer is labeled <NUM>, fiber unit is labeled <NUM>, fiber is labeled <NUM>-a, water-resisting ointment is labeled <NUM>-b, stainless steel tube is labeled <NUM>-c, and plastic protective layer is labeled <NUM>-d.

It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.

<FIG> illustrates a single core submarine cable <NUM>. The cable <NUM> includes a cable core <NUM>, an inner protecting layer <NUM> positioned outside of the cable core <NUM>, and an armor layer <NUM> positioned outside of the inner protecting layer <NUM>. The single core submarine cable <NUM> is used for underwater power transmission, for example, supplying power to coastal cities and transmitting power generated by offshore wind power. The armor layer <NUM> includes first metal wires <NUM> and second wires <NUM> with a constant sum of number. The number of the first and second metal wires is different at least between a first section and a second section.

<FIG> and <FIG> illustrate the cable core <NUM> being positioned at the center of the single core submarine cable <NUM>. The cable core <NUM> includes a water-resistant conductor and a water-resistant filling material positioned in gaps of the water-resistant conductor. The water-resistant conductor is the carrier of electrical current in the single core submarine cable <NUM>. The water-resistant filling material is gap filler material. The water-resistant filling material protects the water-resistant conductor. The water-resistant conductor is in the form of round compacted strand or shaped line. The water-resistant filling material is water-resistant tape, water-resistant powder, water-resistant yarn, water-resistant glue, or a combination thereof.

<FIG> and <FIG> illustrate that the inner protecting layer <NUM> is positioned outside of the cable core <NUM>. The inner protecting layer <NUM> acts as shielding, as insulation, and as protection for the cable core <NUM>. The inner protecting layer <NUM> includes a conductor shielding layer <NUM>, an insulation layer <NUM>, an insulation shielding layer <NUM>, and a first protective layer <NUM> arranged in that order from the inside to the outside. The conductor shielding layer <NUM> is formed by wrapping a semi-conductive binding water-resistant tape and extruding an ultra-smooth semi-conductive shielding material. The insulation layer <NUM> is formed on the conductor shielding layer <NUM> by an even extrusion of the ultra-clean cross-linked polyethylene material. The insulation shielding layer <NUM> is formed on the insulation layer <NUM> by directly extruding the ultra-smooth semi-conductive shielding material. The first protective layer <NUM> includes a water-resistant tape winding layer <NUM>, a metal protective layer <NUM>, a polyethylene protective layer <NUM>, and a lining layer <NUM> arranged in that order from the inside to the outside. The water-resistant tape winding layer <NUM> is formed on the insulation shielding layer <NUM> by overlapping in wrapping semi-conducting resistant tape. The metal protective layer <NUM> is a continuous sealing structure, formed on the water-resistant tape winding layer <NUM> by directly extruding the lead alloy material. The polyethylene protective layer <NUM> is formed on the metal protective layer <NUM> by directly extruding semi-conductive polyethylene or insulating polyethylene thermoplastic sheathing material. The lining layer <NUM> is of high strength polypropylene fiber rope winding structure with a diameter of <NUM>~<NUM>.

<FIG> and <FIG> illustrate that the single core submarine cable <NUM> includes a filling protective layer <NUM> and a fiber unit <NUM>. The single core submarine cable <NUM> is an optoelectric composite cable. The filling protective layer <NUM> is positioned between the polyethylene protective layer <NUM> and the lining layer <NUM>. The fiber unit <NUM> is positioned in gaps of the filling protective layer <NUM>. The filling protective layer <NUM> is a cylinder formed by the continuous extrusion of high strength thermoplastic material, for filling and protecting the fiber unit <NUM>. The fiber unit <NUM> carries optical signals in the single core marine cable <NUM>. The fiber unit <NUM> includes a fiber <NUM>-a, a water-resisting ointment <NUM>-b, a stainless steel tube <NUM>-c, and a plastic protective layer <NUM>-d. The single core marine cable <NUM> includes two groups of fiber units <NUM>. Each fiber unit <NUM> group includes <NUM> fibers.

In an alternative embodiment, the single core marine cable <NUM> includes one, three, or four groups of fiber units. Each group of fiber units <NUM> includes <NUM>~<NUM> fibers. The single core marine cable <NUM> may not include the fiber unit <NUM> and the filling protecting layer <NUM>.

<FIG> and <FIG> illustrate that the armor layer <NUM> includes first metal wires <NUM> and second metal wires <NUM> with a constant sum of number. The armor layer improves the mechanical strength and resistance to erosion and corrosion of the single core marine cable <NUM>. The first metal wires <NUM> are round copper wires, aluminium wires or a combination thereof. The second metal wires <NUM> are round steel wires. The introduction of the first metal wires <NUM> reduces the resistance of the armor and electrical loss through the armor of the armor layer <NUM>. The carrying capacity of the single core submarine cable <NUM> meets the requirements of rated current in specific routes. For example, the rated current required by the single core submarine cable <NUM> is 700A, the carrying capacity of the steel wire armored cable under certain routing conditions is 650A, and the carrying capacity of the copper wire armored cable under the same conditions is 850A. The single core submarine cable <NUM> combines two kinds of metal wires to improve the characteristics of the armor. By calculating the diameter and number of the metal wires, the ratio of number of the first metal wires <NUM> and the second metal wires <NUM> is <NUM>:<NUM>. The carrying capacity of the single core submarine cable <NUM> including the first and second metal wires with ratio of <NUM>:<NUM> under the certain routing conditions is 710A, and this meets the requirements of rated current under those conditions.

The number of the first metal wires <NUM> and the second metal wires <NUM> is different between at least a first section and a second section. By adjusting the ratio of the number of the metal wires in different sections, the single core submarine cable <NUM> meets the requirements of rated current in multiple sections, and optimizes the mechanical strength and cost. For different laying areas and routing conditions, if the cable is prepared with high requirements for routing conditions of a bottleneck section, the carrying capacity of other sections will exceed the preset index. If the cable is prepared with requirements for routing conditions of other sections, the carrying capacity will not meet the high requirements for routing conditions of the bottleneck section. A submarine cable set up to meet high requirements for routing conditions of the bottleneck section has general mechanical performance and high cost. For example, it is assumed that the first section is laid under the routing conditions of other sections, and the second section is laid under the routing conditions of a bottleneck section. The rated current required for the single core submarine cable <NUM> is 700A, the carrying capacity of the first section of the single core submarine cable <NUM> is 720A, and the carrying capacity of the first section of the single core submarine cable <NUM> laid under the routing conditions of the second section is 630A. The carrying capacity of the first section of the single core submarine cable <NUM> laid under the routing conditions of the second section does not meet the rated current required, thus the second section of the route will be a bottleneck section of the route. Referring to the constant sum of the number, the number of the first wires on the second section is increased to improve the carrying capacity of the second section by joining the first wire <NUM> with the second wire <NUM>, the carrying capacity of the first section of the single core submarine cable <NUM> laid under the routing conditions of the second section thus meet the rated current required. The single core submarine cable <NUM> is able to meet the requirements of rated currents in the first and second sections simultaneously. <FIG> and <FIG> illustrate that the first metal wires <NUM> and the second metal wires <NUM> on the first and second sections are continuously arranged around the circumference of the inner protecting layer <NUM>, cross sections of the first metal wires <NUM> and the second metal wires <NUM> are distributed a same circumference surface. The number of the first metal wires <NUM> and the second metal wires <NUM> is different between the first and second sections. The ratio of the number between the first section and the second section of the first wires <NUM> is <NUM>:<NUM>, the ratio of the number between the first section and the second section of the second wires <NUM> is <NUM>:<NUM>, the sum of the number of the first metal wires <NUM> and the second metal wires <NUM> always being constant. The carrying capacity of the first section can be 720A, and the carrying capacity of the second section can be 710A, both of which meet the preset rated current requirements of 700A. An outer protecting layer <NUM> is positioned outside of the armor layer <NUM>, the outer protecting layer <NUM> provides mechanical protection and corrosion resistance to the armor layer <NUM>, the outer protecting layer <NUM> is formed by wrapping the polypropylene fibers with diameter of <NUM>~<NUM> and coating with pitch or the like.

In an alternative embodiment, not covered by claims, the first metal wires <NUM> and the second metal wires <NUM> are flat wires. The first metal wires <NUM> are of aluminum or a combination of aluminum and copper. The number of the first metal wires <NUM> and the second metal wires <NUM> has more than two groups of different values on different sections of the single core submarine cable <NUM>. To meet the requirements of rated current, the number of the first metal wires <NUM> is reduced and the number of the second metal wires <NUM> is increased to optimize mechanical strength and reduce cost of the single core submarine cable <NUM>. The first metal wires <NUM> and the second metal wires <NUM> are arranged continuously but irregularly. The material of the outer protecting layer <NUM> can be polyethylene, polypropylene, polyvinylchloride, polyolefin, or a combination thereof.

The single core submarine cable of the present disclosure meets the requirements of rated current in multiple sections with different routing conditions, and optimizes the mechanical strength and cost.

Claim 1:
A single core submarine cable (<NUM>) comprising:
a cable core (<NUM>);
an inner protecting layer (<NUM>) positioned outside of the cable core (<NUM>); and
an armor layer (<NUM>) positioned outside of the inner protecting layer (<NUM>), wherein the single core submarine cable comprises a first section and a second section, characterized in that, the armor layer (<NUM>) comprises first metal wires (<NUM>) and second metal wires (<NUM>) with a constant sum of number in the first section and the second section of the single core submarine cable (<NUM>), the number of the first metal wires (<NUM>) and the second metal wires (<NUM>) is different between the first section and the second section, the first metal wires (<NUM>) and the second metal wires (<NUM>) on the first and second sections are continuously arranged around the circumference of the inner protecting layer (<NUM>), wherein the first metal wires (<NUM>) are copper wires, aluminium wires, or a combination thereof and the second wires (<NUM>) are steel wires.