Patent Application
20120204590
The invention relates in particular to the field of circuit breakers or disconnectors for medium-voltage generators, placed in a protective sheath, and using cooling devices called “heat pipes” that operate with a phase-change heat-transfer fluid.
The constant concern of makers of that type of equipment is to increase the ability of such gear to conduct higher and higher currents, in particular for circuit breakers and disconnectors placed inside busbars at the outlets of power stations for producing or distributing electricity. That applies particularly for alternator circuit breakers.
A method that is generally used consists in making more uniform the temperature of the air that is in contact with the various heating and heated parts of the circuit breaker concerned. The cooling inside such a protective sheath may take place by natural or forced convection of the air enclosed therein and in which the circuit breaker is to be found, the prevailing temperature inside the protective sheath being considerably higher than the prevailing temperature outside, by 30° C. to at least 40° C. However, the use of such auxiliary gear, such as ventilators, presents various drawbacks, which are: high electricity consumption on the main circuit, risk of losing auxiliary ventilators and consequently the need for duplicating them or for providing for degraded operating modes, noise, and considerable bulkiness. Another solution consists in providing an increase in the current flow section in the various transmission elements, and thus increasing the size of circuit breaker parts.
Patent document EP 1 657 731 describes a known cooling device and method for cooling a high-voltage disconnector or a circuit breaker.
The object of the invention is to propose a different solution for cooling switchgear.
To this end, the invention mainly provides a cooling device for cooling medium-voltage switchgear placed inside a protective sheath, in order to evacuate a portion of the heat delivered by the switchgear, the device comprising:
evaporators operating with a phase-change heat-transfer fluid, and being placed around the casing of the switchgear;
condensers placed above the protective sheath; and
a box surrounding the top of the assembly,
According to the invention, the evaporators and the condensers are in electrical contact with the medium-voltage switchgear, and insulating parts are used for insulating the condensers relative to the roof of the sheath and to the box.
In a preferred embodiment, the insulating parts, relative to the roof of the protective sheath, are constituted by a central portion of the roof of the protective sheath and on which the condensers rest.
In this preferred embodiment, side partitions are used for channeling the streams of air reaching the condensers from the side.
In a particular embodiment of the device of the invention, side ventilation means may be added to the device.
The invention and its various technical characteristics can be better understood on reading the following description, accompanied by several figures in which, respectively:
With reference to
The top portion of the evaporators 11 is connected to at least one pipe 14 that passes through the roof 16 of the sheath 15. Each pipe 14 leads to a condenser 21, which is placed on the roof 16 of the sheath 15. The condenser(s) 21 are themselves placed inside a box 20, which is placed above the sheath 15, and they are subjected to a flow of air, in particular passing through side walls 22 having air passages and through a top space 25 of the box 20, the space being just below the roof 16 of the box.
Thus, the evaporators 11 operate with a phase-change heat-transfer fluid, installed along the walls of the circuit breaker casing, and possibly the disconnector casing, evacuating a portion of the heat of the casing, which is at a temperature of 100° C. These evaporators 11 therefore transmit the heat by means of the pipe 14 to the condenser 21, which is placed above the sheath. It should be remembered that the evaporators 11, the pipes 14, and the condensers 21 are in electrical contact with the circuit breaker 10. Thus, it is no longer necessary to consider insulating them electrically relative to the circuit breaker.
Just like the live assembly 12 composed of the circuit breaker 10, the evaporators 11, the pipes 14 and the condensers 21, which is insulated relative to the sheath 15, provision is made for the condensers 21 also to be insulated relative to the roof 16 of the sheath 15 and to the box 20 and in particular to the side walls 22 thereof. To do this, the roof 16 of the sheath 15 includes an insulating central portion 17, which central portion fills in a gap between two side portions 19 of the roof and supports the condensers 21. In addition, side partitions 24 are provided on either side of the condensers 21 extending to the side walls 22 of the box 20, in order to channel the streams of air reaching the condensers 21 from the side. These supporting side partitions are made from insulating material. Thus, the various cooling elements of the circuit breaker 10 are electrically insulated relative to the infrastructure in which they are placed.
It should be noted that the evaporators 11 that surround the walls of the circuit breaker 10 casing, may similarly be replaced by reservoirs on its surface, possibly comprising a plurality of reservoir parts.
In
The advantages of the device of the invention are that it does not consume energy and that its development and implementation do not require an insulating cooling system to be designed, thereby saving time when developing such an installation.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0957481 | Oct 2009 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/066015 | 10/25/2010 | WO | 00 | 4/17/2012 |
