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

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.

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.