Arrangement For Cooling Components Of A Subsea Electric System

• US 20170112021A1
• Filed: 03/03/2015
• Published: 04/20/2017
• Est. Priority Date: 04/04/2014
• Status: Active Grant

• Current Assignee: ABB Schweiz AG (ABB Limited)
• Original Assignee: ABB Schweiz AG (ABB Limited)
• Inventors: Laneryd, Tor, Gradinger, Thomas
• Granted Patent: US 10,390,459 B2
• Time in Patent Office: Days
• CPC Class Codes: F28D 1/022 for immersion in a natural body of water, e.g. marine radiators
• CPC Class Codes: F28D 15/00 Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies F28D17/00, F28D19/00, F28D20/00 take precedence
• CPC Class Codes: F28F 13/12 by creating turbulence, e.g. by stirring, by increasing the force of circulation F28F13/08 takes precedence
• CPC Class Codes: H05K 5/0017 with operator interface units
• CPC Class Codes: H05K 7/14337 specially adapted for underwater operation
• CPC Class Codes: H05K 7/20236 by immersion
• CPC Class Codes: H05K 7/20245 by natural convection; Thermosiphons
• CPC Class Codes: H05K 7/20263 Heat dissipaters releasing heat from coolant
• CPC Class Codes: H05K 7/20272 Accessories for moving fluid, for expanding fluid, for connecting fluid conduits, for distributing fluid, for removing gas or for preventing leakage, e.g. pumps, tanks or manifolds
• CPC Class Codes: H05K 7/20409 Outer radiating structures on heat dissipating housings, e.g. fins integrated with the housing
• CPC Class Codes: H05K 7/20927 Liquid coolant without phase change

Abstract

An arrangement for cooling components of a subsea electric system including a tank filled with a dielectric fluid. The tank includes first and second sections. The arrangement includes one first electric component within the first section, and one second electric component within the second section. The arrangement includes a first heat exchanger located outside the tank and in fluid contact with the tank, and arranged during operation to be in thermal contact with sea water. The arrangement includes a pump arranged to force a flow of dielectric fluid through the first heat exchanger. Flow of dielectric fluid in the tank is by both natural and forced convection generated by the pump. The first electric component generates more heat than the second electric component. Within the first section the share of the flow by natural convection is greater than within the second section.

Claims

1. An arrangement for cooling components of a subsea electric system, comprising:

a tank filled with a dielectric fluid, the tank comprising a first section and a second section;

at least one first electric component located within the first section;

at least one second electric component located within the second section;

a first heat exchanger located outside the tank and in fluid contact with the tank, and arranged to during operation be in thermal contact with sea water; and

a pump arranged to force a flow of the dielectric fluid through the first heat exchanger;

wherein flow of the dielectric fluid in the tank is partially by natural convection and partially by forced convection generated by the pump,

characterized in that the at least one first electric component generates more heat than the at least one second electric component, and in that within the first section the share of the flow by natural convection is greater than within the second section.

2. The arrangement according to claim 1, further comprising at least one further first heat exchanger located outside the tank and in fluid contact with the tank, and arranged to during operation be in thermal contact with sea water.

3. The arrangement according to claim 2, wherein each at least one further first heat exchanger is provided with a respective further pump arranged to force a flow of the dielectric fluid through its respective first heat exchanger.

4. The arrangement according to claim 1, further comprising at least one second heat exchanger located inside the tank and in thermal connection with at least one of the electric components.

5. The arrangement according to claim 4, wherein the flow of dielectric fluid through the at least one second heat exchanger is by natural convection.

6. The arrangement according to claim 4, wherein the at least one second heat exchanger is a heat sink, such as a finned heat sink.

7. The arrangement according to claim 1, wherein at least two first high-loss generating electric components are provided in an essentially vertical stack in the first section.

8. The arrangement according to claim 1, wherein at least one second temperature sensitive, low-loss generating electric component is provided in the second section.

9. The arrangement according to claim 1, wherein the second section is defined by a separate flow path, and wherein for a common mean fluid velocity, frictional pressure drop through the at least one second electric component is lower than that through the at least one first electric component.

10. The arrangement according to claim 9, wherein the separate flow path is inside the tank itself.

11. The arrangement according to claim 1, wherein the first heat exchanger comprises at least one tube through which the dielectric fluid flows.

12. The arrangement according to claim 10, wherein the at least one tube is shaped like a coil or a spiral.

13. The arrangement according to claim 1, wherein the first heat exchanger comprises mixing means for mixing the flow of the dielectric fluid through the first heat exchanger.

14. The arrangement according to claim 13, wherein the mixing means is a static mixer comprising alternating helices.

15. The arrangement according to claim 1, further comprising:

an electrical control system, the electrical control system being provided in the tank and connected to the at least one electric component.

16. The arrangement according to claim 15, wherein the electrical control system is a subsea power-electronic converter unit.

17. The arrangement according to claim 15, wherein the electrical control system comprises at least one of any of:

a switchgear, a breaker, a transformer, a tap changer, and a capacitor.

18. The arrangement according to claim 1, wherein the at least one first electric component is any of:

a switchgear, a breaker, a transformer, a tap changer, and a capacitor.

19. The arrangement according to claim 1, wherein the dielectric fluid flows from the tank into the first heat exchanger at an outlet of the tank and flows back into the tank from the first heat exchanger at an inlet of the tank, and wherein the arrangement is configured such that during operation the outlet is located vertically higher than the inlet.