Offshore system comprising a dynamic submarine power cable
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.
1 . An offshore system comprising:
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:
A) the offshore structure tube has an inner tube channel in fluid communication with the longitudinal water channel, and wherein 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,
wherein the longitudinal water channel extends from the top end to the lower end of the bend stiffener along the entire length of the dynamic submarine power cable arranged in the bend stiffener,
wherein at an interface between the bend stiffener and the dynamic submarine power cable where the dynamic submarine power cable enters the lower end of the bend stiffener, the outer surface of the dynamic submarine power cable and an outer surface of the bend stiffener form outermost surfaces of the offshore system.
2 . The offshore system as claimed in claim 1 , wherein the offshore structure tube is an I-tube.
3 . The offshore system as claimed in claim 2 , wherein the through-opening or radial through-opening is arranged underwater.
4 . The offshore system as claimed in claim 2 , wherein the dynamic submarine power cable is a high voltage power cable rated for a voltage of at least 33 kV.
5 . The offshore system as claimed in claim 2 , wherein the dynamic submarine power cable extends inside the inner tube channel of the offshore structure tube.
6 . The offshore system as claimed in claim 2 , comprising an offshore floating structure, wherein the offshore structure tube forms part of the offshore floating structure.
7 . The offshore system as claimed in claim 1 , wherein the bend stiffener is a submerged bend stiffener.
8 . The offshore system as claimed in claim 1 , wherein the through-opening or radial through-opening is arranged underwater.
9 . The offshore system as claimed in claim 1 , wherein the dynamic submarine power cable is a high voltage power cable rated for a voltage of at least 33 kV.
10 . The offshore system as claimed in claim 1 , wherein the dynamic submarine power cable extends inside the inner tube channel of the offshore structure tube.
11 . The offshore system as claimed in claim 1 , comprising an offshore floating structure, wherein the offshore structure tube forms part of the offshore floating structure.
12 . The offshore system as claimed in claim 11 , wherein the offshore floating structure is one of a floating wind turbine, a floating substation, a floating hydrocarbon platform or a floating hydrocarbon vessel.
13 . A method of cooling a dynamic submarine power cable of an offshore system having 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 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 wherein 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,
the method comprising:
providing the bend stiffener such that the lower end is submerged in seawater, causing seawater to enter the longitudinal water channel,
wherein the longitudinal water channel extends from the top end to the lower end of the bend stiffener along the entire length of the dynamic submarine power cable arranged in the bend stiffener,
wherein at an interface between the bend stiffener and the dynamic submarine power cable where the dynamic submarine power cable enters the lower end of the bend stiffener, the outer surface of the dynamic submarine power cable and an outer surface of the bend stiffener form outermost surfaces of the offshore system.
14 . The method as claimed in claim 13 , wherein the seawater flows along the longitudinal water channel and exits the through-opening or radial through-opening by natural convection.
15 . The method as claimed in claim 13 , wherein the through-opening or radial through-opening is arranged underwater.