NKT HV Cables AB

A method of joining a first conductor of a power cable with an essentially cylindrical metal element, the method including: a) arranging an end section of the first conductor and a portion of the metal element in a metal fixture, b) penetrating the metal fixture with a rotating friction stir welding, FSW, tool, c) moving the rotating FSW tool, while penetrating the metal fixture, towards and through an interface between the end section of the first conductor and the metal element, joining the end section, the metal element, and the metal fixture, and d) removing excess metal fixture material from the joined end section and metal element to obtain an FSW joint between the first conductor and the metal element.

An offshore system including: a dynamic submarine power cable, a bend stiffener having a lower end and a top end, the bend stiffener having a central channel extending from the lower end to the top end, the central channel receiving the dynamic submarine power cable with a radial spacing between an inner surface of the central channel and an outer surface of the dynamic submarine power cable along the length of the dynamic submarine power cable arranged in the bend stiffener, the radial spacing forming a longitudinal water channel between the bend stiffener and the dynamic submarine power cable, and an offshore structure tube connected to the bend stiffener, wherein the offshore structure tube has an inner tube channel in fluid communication with the longitudinal water channel, and wherein A) the offshore structure tube has a through-opening extending from the inner tube channel through a wall of the offshore structure tube to enable water flowing from the lower end through the bend stiffener to exit the offshore structure tube via the through-opening to provide water cooling of the dynamic submarine power cable in the bend stiffener, or B) the bend stiffener has a radial through-opening arranged within ¼ of a total axial length of the bend stiffener, defined by a distance between the lower end and the top end, from the top end to enable water flowing from the lower end through the bend stiffener to exit the bend stiffener via the radial through-opening to provide water cooling of the dynamic submarine power cable in the bend stiffener.

A heating assembly configured to receive a power cable for restoring an insulation system of the power cable, the heating assembly including: a central pressurisation and heating structure, and a first and second lateral structure provided at a respective axial end of the central pressurisation and heating structure, the first and second lateral structure each having at least a 20 cm long axially extending section primarily made of a material at most having a conductivity of the order of 1000 S/m at 20° C.

A power cable including: a conductor extending along a center axis; an insulation system including at least a first semiconducting layer provided around the conductor, and an insulation layer provided around the first semiconducting layer; wherein the insulation layer includes: a) 60 to 90 wt % polypropylene; b) 5 to 20 wt % styrene block copolymer; c) 1 to 6 wt % dielectric fluid; and d) 0 to 15 wt % polyethylene.

A submarine power cable bundle including: a first bottom direct current, DC, submarine power cable, a second bottom DC submarine power cable, and a top DC submarine power cable, wherein the first bottom DC submarine power cable and the second bottom DC submarine power cable are bundled together by means of a first elongated bundling element, forming a first bundle, wherein the first bundle is bundled together with the top DC submarine power cable by means of a second elongated bundling element, forming a trefoil configuration, wherein the first elongated bundling element bundles the first bundle tighter than the second elongated bundling element bundles the first bundle and the top DC submarine power cable.

There is provided a power cable including a conductor extending along a centre axis; an insulation system including at least a first semiconducting layer surrounding the conductor, and an insulation layer surrounding the first semiconducting layer; wherein the insulation layer includes a) 40-94 wt % LDPE; and b) 6-60 wt % PS and/or styrene block copolymer, wherein the weight percentages are based on the insulation layer as a whole.

A method of performing a quality inspection of a vulcanized joint of a power cable during manufacturing of the vulcanized joint, the method comprising: a) obtaining, from a laser scanner, measurements of an outer surface of an inner semiconducting layer provided over a conductor joint which joints conductors of two power cable sections, and of a transition area between the outer surface and outer surfaces of a respective inner semiconducting layer of the two power cable sections, b) obtaining, from a laser scanner, measurements of an outer surface of a tapering section of an insulation layer arranged around a respective one of the inner semiconducting layers of the two cable sections, c) processing the measurements obtained in step a) and in step b), the processing involving generating one or a respective 3-d model of the outer surfaces and evaluating an outer surface quality of the outer surfaces based on the one or more 3-d models, d) presenting a conclusion regarding surface quality based on the evaluation, e) obtaining, from a laser scanner, measurements of an outer surface of a joint insulation arranged around the inner semiconducting layer that is provided over the conductor joint, the joint insulation having been provided over the inner semiconducting layer provided around the conductor joint after step d), and f) processing measurements obtained from the laser scanner in step e), the processing involving determining an insulation thickness or an outer diameter of the joint insulation, and g 1 ) presenting the insulation thickness or outer diameter, and/or, g 2 ) evaluating the insulation thickness or outer diameter, and presenting a conclusion regarding the insultation thickness or outer diameter based on the comparison.

A method of making a joint of a power cable, including: a) providing two cable sections to be jointed, each cable section including a conductor having a conductor end, and an insulation system including an inner semiconducting layer arranged around the conductor, an insulation layer arranged radially outside the inner semiconducting layer, and an outer semiconducting layer arranged radially outside the insulation layer, b) mechanically processing the insulation system of each cable section by gradually increasing a radius of the insulation layer in an axial direction away from the conductor end of the cable section, to obtain a tapering insulation layer section that tapers towards the conductor end, wherein the processing is performed such that an outer surface of a radially innermost portion of the tapering insulation layer section, interfacing the inner semiconducting layer, obtains a first inclination relative to a longitudinal axis of the cable section, and that an outer surface of an intermediate portion of the tapering insulation layer section obtains a second inclination which is larger than the first inclination, wherein the outer surface of the radially innermost portion transitions smoothly to the outer surface of the intermediate portion, and c) making a joint insulation system, after the conductors of the two cable sections have been electrically connected to each other by means of a conductor joint, the joint insulation system connecting to the inner semiconducting layer of each cable section, to the tapering insulation layer section of each cable section, and to the outer semiconducting layer of each cable section.

A dynamic submarine power cable for deep-sea applications, including: a conductor, an insulation system arranged around the conductor, the insulation system including an inner semiconducting layer arranged around the conductor, an insulation layer arranged around the inner semiconducting layer, and an outer semiconducting layer arranged around the insulation layer, a bedding layer arranged around the insulation system, and a longitudinally welded corrugated metallic water barrier arranged around the bedding layer, wherein the bedding layer fills the corrugations of the corrugated metallic water barrier, wherein the bedding layer includes a single layer which has an initial stiffness at onset of compressive stress to provide structural support against external hydrostatic pressure exerted on the metallic water barrier, and an increased elasticity as compared to the initial stiffness when the compressive stress has reached a stress threshold to absorb cyclic thermal expansion and contraction of the insulation layer, or wherein the bedding layer includes an outer layer and an inner layer, wherein the outer layer fills the corrugations and is stiffer than the inner layer and provides structural support against external hydrostatic pressure exerted on the corrugated metallic water barrier, the inner layer providing elasticity to absorb cyclic thermal expansion and contraction of the insulation layer.

A cable end preparation device for preparing a cable end section, the cable end preparation device including a plurality of guides configured to contact a periphery of the cable end section during operation of the end preparation device, and a cutter, the cable end preparation device being configured to be operated in: a first mode, in which the cutter is fixed in relation to at least half of the guides during operation of the cable end preparation device, and a second mode, in which the cutter is allowed to move in relation to a majority of the plurality of guides of the plurality of guides during operation of the cable end preparation device.