Cooling apparatus for switchgear with heat pipe structure having integrated busbar tube

1. A cooling apparatus for a switchgear, the switchgear having at least one primary contact constructed and arranged to connect to a terminal of a circuit breaker, the cooling apparatus comprising:

an evaporator integral with the at least one primary contact, such that an evaporator chamber of the evaporator is defined within the at least one primary contact,

a condenser located at a higher elevation than the evaporator,

fluid conduit structure fluidly connecting the evaporator with the condenser, a portion of the fluid conduit structure defining a busbar tube electrically connected with the at least one primary contact and defining a busbar of the switchgear, and

working fluid in the evaporator chamber so as to be heated to a vapor state, with the fluid conduit structure being constructed and arranged to transfer the vapor to the condenser and to passively return condensed working fluid back to the evaporator chamber for cooling the at least one primary contact and the associated busbar tube,

wherein the apparatus is in combination with a plurality of primary contacts, wherein each evaporator comprises an evaporation chamber formed in an associated primary contact, and

wherein each evaporation chamber has a closed first end proximate the circuit breaker and an opened end opposite the closed end, the busbar tube being sealingly coupled to the opened end.

2. The apparatus of claim 1 , wherein in the busbar tube is made of electrically conductive material and is constructed and arranged to carry current of about 4000 A.

3. A cooling apparatus for a switchgear, the switchgear one or more primary contacts constructed and arranged to connect to a terminal of a circuit breaker, the cooling apparatus comprising:

an evaporator constructed and arranged to be associated with each primary contact,

a condenser located at a higher elevation than the evaporator,

fluid conduit structure fluidly connecting the evaporator with the condenser, a portion of the fluid conduit structure defining a busbar tube electrically connected with an associated primary contact and defining a busbar of the switchgear, and

working fluid in the evaporator so as to be heated to a vapor state, with the fluid conduit structure being constructed and arranged to transfer the vapor to the condenser and to passively return condensed working fluid back to the evaporator for cooling the one or more primary contacts and the associated busbar tube,

wherein in the busbar tube is made of electrically conductive material and is constructed and arranged to carry current of about 4000 A, and

wherein the busbar tube is copper having an inner diameter of about 12 mm and an outer diameter of about 40 mm.

4. The apparatus of claim 1 , wherein a first end of the busbar tube is sealingly connected with an associated primary contact.

5. The apparatus of claim 4 , wherein in the first end is a flanged end coupled to the associated primary contact with a metal sealing ring there-between.

6. The apparatus of claim 1 , wherein the busbar tube includes an internal cavity, a liquid-return tube of the fluid conduit structure being disposed in the internal cavity and in communication with the evaporator, whereby vapor is directed from the evaporator through the internal cavity and to the condenser, with the condensed working fluid being directed from the condenser and through the liquid-return tube back to the associated evaporator.

7. The apparatus of claim 1 , wherein at least a portion of the fluid conduit structure is electrically insulating.

8. The apparatus of claim 7 , wherein the working fluid is electrically insulating and selected from the group consisting of hydrofluorocarbon, fluoroketone, and hydrofluoroether refrigerants, and any mixtures thereof.

9. The apparatus of claim 4 , wherein at least a portion of the fluid conduit structure is electrically insulating and is coupled to a second end of the busbar tube.

10. The apparatus of claim 1 , further comprising a bushing plate, each primary contact being removably coupled to the bushing plate.

11. The apparatus of claim 1 , wherein the fluid conduit structure comprises:

a liquid-return tube disposed in an internal cavity of the busbar tube and in communicating between an associated evaporator and the condenser,

electrically insulating tubing structure connected to the busbar tube and having an internal cavity, and

condenser tubing structure coupled to the insulating tubing structure and having an internal cavity,

wherein the internal cavities of the busbar tube, the insulating tubing structure and the condenser tubing structure are in fluid communication such that the vapor is directed from the associated evaporator, through the internal cavities to the condenser and the condensed working fluid is directed from the condenser, through the liquid-return tube back to the associated evaporator.

12. The apparatus of claim 1 , wherein each primary contact and associated busbar tube is made of aluminum.

13. A method of cooling a switchgear having at least one primary contact constructed and arranged to connect to a terminal of a circuit breaker, the method comprising the steps of:

providing an evaporator integral with the primary contact, such that an evaporator chamber of the evaporator is defined within the at least one primary contact,

providing a condenser located at a higher elevation than the evaporator,

providing fluid conduit structure fluidly connecting the evaporator with the condenser, and providing a working fluid in the evaporator,

electrically connecting a busbar tube of the fluid conduit structure with the primary contact to define a busbar of the switchgear, wherein the evaporation chamber has a closed first end proximate the circuit breaker and an opened end opposite the closed end, the busbar tube being sealingly coupled to the opened end,

transferring heat from the primary contact and the busbar tube to the working fluid to cause the working fluid to evaporate in the evaporator with the evaporated vapor being delivered to the condenser via the fluid conduit structure, and

passively returning the working fluid that condenses in the condenser to the evaporator chamber via the fluid conduit structure.

14. The method of claim 13 , wherein the busbar tube includes an internal cavity and the step of providing the fluid conduit structure includes providing a liquid-return tube in the internal cavity and in communication with the evaporator, whereby the step of transferring heat includes directing vapor from the evaporator through the internal cavity and to the condenser, with condensed working fluid being directed from the condenser and through the liquid-return tube back to the evaporator.

15. The method of claim 13 , wherein the step of electrically connecting the busbar tube includes providing the busbar tube of electrically conductive material so as to carry current of about 4000 A.

16. The method of claim 15 , wherein the busbar tube is provided from copper and has an inner diameter of about 12 mm and an outer diameter of about 40 mm.

17. The method of claim 13 , wherein the working fluid is provided as an electrically insulating working fluid and the fluid conduit structure includes at least a portion that is electrically insulating.