JPS631012A - Directly buried type transformer - Google Patents

Abstract

PURPOSE:To make it possible to bury a transformer directly in the ground for employment, by using a heat pipe to carry heat generated from a coil member to a heat-radiating member and by using a corrugated tube as a container for the heat pipe. CONSTITUTION:An insulating oil 5 fills a closed vessel 2, and a spiraled heat pipe 6 surrounding a coil member 1 on one end side is immersed in said insulating oil 5. On the other hand, the other end of the pipe 6 is led outside the vessel 2 and disposed in a heat-radiating member 7. The pipe 6 has a construction wherein a condensable fluid is injected as an operating fluid inside a closed corrugated tube 8 after a noncondensable gas is exhausted therefrom to make the inside of the tube vacuum and wherein a wick 10 having a porous structure to cause a capillary pressure inside the tube 8 is arranged. Thereby heat emitted from the coil 1 is released into the air by the pipe 6, and consequently a rise in the temperature of a transformer as a whole is prevented. The transformer having this construction can be buried directly in the ground for employment without providing a handhole.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a transformer, and particularly to a type of transformer installed underground.

Conventional technology It is well known that underground wiring is used when overhead service lines intersect in a complicated manner, such as in a busy shopping district. There are known methods for converting Conventionally, underground transformers used in this power distribution system are installed in handholes (underground holes) in sidewalks, and the handholes are covered with gratings. It has a closed configuration.

Problems to be Solved by the Invention However, in order to promote heat dissipation from the transformer body and suppress its temperature rise, the handhole has to be much larger than the transformer body, which requires construction work. The problem of high initial costs often occurred. In addition, since it is necessary to use a lid such as a grating with an opening to dissipate heat into the air, it is possible to prevent dirty water and dust from entering the hand hole. There were problems that required maintenance.

The above problem is due to the need to take heat dissipation measures to prevent the temperature rise caused by the heat generated by the transformer. It is conceivable to install a pipe to actively dissipate heat. However, in that case, the requirements must be met, such as securing a sufficient area for receiving heat from the transformer, having good durability and workability, and ensuring that abnormalities such as dryout and reduction in heat transport capacity do not occur. Therefore, simply attaching a heat pipe to an existing transformer is not practical.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transformer that can be directly buried underground without the need for conventional hand holes.

Means for Solving the Problems In order to achieve the above object, the present invention immerses the coil section that directly performs voltage transformation in insulating oil in a closed container, and also immerses it inside a corrugated pipe with a closed structure. After exhausting the non-condensable gas, one end of the heat pipe, which is formed by enclosing a condensable working fluid and a porous wick that generates capillary pressure, is spirally wound inside the closed container so as to surround the coil part. The heat pipe is wound into a shape and immersed in the insulating oil, and the other end of the heat pipe is pulled out from the sealed container and placed in a heat radiating section at a temperature below the temperature to be maintained.

Function: Therefore, in the transformer of the present invention, the heat generated from the coil section is first transferred to the insulating oil, and then the working fluid in the heat pipe is heated and evaporated, and the vapor is transferred to the end of the heat radiating section. It flows into the air, dissipates heat, and condenses into liquid. That is, the heat pipe carries the heat generated from the coil section to the heat radiation section to cool the transformer itself. In that case,
In this invention, since the heat pipe is commercially available with a corrugated pipe as a container, it is possible to secure a sufficiently large heat receiving area without attaching any fins. This can be done easily without causing buckling, and since the working fluid in a roughly liquid phase does not flow down to the lower end of the heat pipe in its entirety, it accumulates in the uneven part of the heat pipe. It is dispersed during the rest of the part that becomes the heating part, and can prevent dryout and the accompanying decrease in heat transport ability.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention, in which two coil units 1 that directly perform voltage transformation are arranged vertically in a closed container 2. It has a robust construction to withstand external pressure when buried underground, and is provided with a high voltage cable lead-in part 3 and a low-voltage cable lead-out part 4 at its upper end. The inside of the airtight container 2 is filled with enough insulating oil 5 to completely immerse the coil portion 1, and one end of the spirally wound heat vibrator is placed in the upper side of the insulating oil 5. It is immersed in a state surrounding the coil part 1 of. The other end of the heat vibro is drawn out from the upper end of the closed container 2 and placed in a predetermined heat radiating section 7 .

Here, as shown in a partial cross-sectional view in FIG. 2, the Heat Vibro evacuates non-condensable gas such as air from the inside of a sealed corrugated tube 8 with annular irregularities, and then pumps condensable fluid such as water. A wick 10 having a porous structure such as a wire mesh is arranged to inject the working fluid 9 and to generate capillary pressure inside the corrugated pipe 8. One end side of the three heat vibros with such a configuration is the third
As shown schematically in the figure, it is spirally wound at a predetermined pitch to surround the coil portion 1, and the lead angle (inclination angle) θ at the spiral portion is on the inner peripheral side of the corrugated pipe 8. The angle is set to about 2 to 10 degrees so that a liquid pool 11 is formed at the angle. In addition, the heat dissipation section 7 is essentially a part that releases the heat carried by the heat vibro, and since the temperature that the transformer should maintain is generally below atmospheric temperature, the heat dissipation section 7 simply connects the end of the heat vibro to the atmosphere. The structure may be such that the inside is exposed, or the structure may be configured to actively perform cooling or water cooling.

FIG. 4 is a schematic diagram showing the usage state of the transformer constructed as described above, in which the entire transformer is buried underground as it is, and the other ends of Bee 1 to Vibro are pulled out into the atmosphere. At the same time, fins 12 are attached to form a heat radiating section 7. The temperature of the insulating oil 5 filled inside the sealed container 2 rises due to the heat generated in the coil part 1 due to power transmission.
The heat is further applied to the end of the helically wound heat vibro, and as a result, the helical part of the heat vibro becomes a heating part, and the working fluid 9 inside it evaporates, and the vapor changes in temperature and pressure. It flows to the end on the side of the lower heat radiation part 7, radiates heat, and condenses and liquefies. That is, the heat generated by the coil portion 1 is released into the atmosphere by the heat vibro, thereby preventing the temperature of the transformer as a whole from rising. In this case, the heat vibro has a large surface area because the container is a corrugated pipe 8, and therefore a sufficiently large heat receiving area can be secured within the closed container 2 without attaching fins or the like. In addition, since the heat vibro has flexibility due to the use of corrugated tube 8, it can be easily bent into a spiral shape, so there is no decrease in durability due to buckling, and the transformer as a whole is Manufacturability is improved. Further, the working fluid 9 condensed and liquefied in the heat dissipation section 7 flows down due to the capillary pressure and gravity caused by the wick 10, but it accumulates little by little in the uneven portions formed on the inner circumferential surface of the corrugated tube 8 and accumulates in the spiral portion, that is, the heating portion. Since the heat receiving part of the heat exchanger is dispersed over the whole area, the heat receiving part of the heat exchanger becomes extremely wide.In other words, there is no part where dryout occurs due to heat input, and therefore, the risk of a decrease in heat transport ability can be prevented. In particular, if the lead angle of the helical portion is set to about 2 to 10', the liquid pool 11 is reliably and sufficiently formed, so that good heat transport ability can be maintained.

Therefore, even if the above-mentioned transformer is buried underground and placed in an insulated or heat-retaining state, it can dissipate heat and cool down by heat vibro, so there is no rise in temperature or problems associated with it. Then, in the above transformer, the hand hole is 39. It can be used by being buried directly underground without being destroyed.

Effects of the Invention As is clear from the above explanation, according to the transformer of the present invention, heat can be directly conveyed from the inside of the sealed container containing the coil section to a predetermined heat radiating section for cooling. It can be used by being directly buried underground without providing a hand hole, thus reducing the space required and keeping equipment costs low. In addition, since this invention uses a corrugated pipe as a container for the heat pipe that carries heat to the heat dissipation section, it is easy to wind it in a spiral to surround the coil section that directly transforms the voltage, and at the same time The heat receiving area can be expanded. The rough edges on the inner circumference of the corrugated pipe act as pools of hydraulic fluid, allowing the hydraulic fluid to be dispersed throughout the area that receives heat from the insulating oil, thereby preventing dry-out where the hydraulic fluid runs out. Since the substantial heat-receiving area can be widened, the heat transport ability can be maintained in a good state. Overall, this invention provides an underground transformer with excellent cooling performance.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a schematic sectional view showing a part of the heat pipe, and FIG. 3 is a partial view showing an example of a spiral portion of the heat pipe. FIG. 4 is a schematic diagram of the state of use. DESCRIPTION OF SYMBOLS 1... Coil part, 2... Airtight container, 5... Insulating oil, 6... Heat pipe, 7... Heat radiation part, 8.
... Corrugated pipe, 9... Working fluid, 10...
Wick.

Claims (1)

[Claims] A porous structure in which the coil section that directly transforms voltage is immersed in insulating oil in a sealed container, and a condensable working fluid and capillary pressure are generated after non-condensable gas is exhausted inside the sealed corrugated pipe. One end of a heat pipe formed by enclosing a wick is spirally wound so as to surround the coil part inside the airtight container and immersed in the insulating oil, and the other end of the heat pipe is immersed in the insulating oil. A directly buried type transformer, characterized in that the transformer is pulled out from the sealed container and placed in a heat dissipation section whose temperature is below the temperature to be maintained.