JP2001160512A - Oil-immersed electrical apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease insulating oil in amount so as to obtain an oil-immersed electrical apparatus lessened in weight by a method wherein the shape of the tank ceiling of the oil- immersed electrical apparatus is so determined as to ensure a necessary insulation distance from a high-voltage connection lead. SOLUTION: An oil-immersed electrical apparatus has such a structure in which a coil group composed of a high-voltage coil and a low-voltage coil which overlap with each other and a core are housed in a tank, the high-voltage coil is connected to a high-voltage connection lead arranged at a certain position so as to ensure a prescribed insulation distance from the upper end of the low-voltage coil, the low-voltage coil is connected to a low-voltage connection lead arranged at a certain position so as to ensure a prescribed insulation distance from the upper end of the low-voltage coil, the high-voltage connection lead, and the inner wall of the upper tank, and the tank is filled up with insulating oil for the formation of the oil-immersed electrical apparatus. The tank ceiling of the oil-immersed electrical apparatus is provided with a flat which is set high enough to ensure an insulation distance corresponding to the surface potential of the low-voltage connection lead, and a part of the tank ceiling corresponding to the high-voltage connection lead is formed into a semicylindrically protrudent part so as to enable its inner face to be located at a certain position to ensure an insulation distance corresponding to the surface potential of the high-voltage connection lead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-filled electric device such as a transformer and a reactor installed in a power plant or a substation.

[0002]

2. Description of the Related Art Oil-filled electric equipment such as a transformer and a shunt reactor used in an electric power system has a structure in which a coil and an iron core are housed in a tank and filled with insulating oil. For example, in the case of a shell-type transformer, it is configured as shown in FIG. 4, FIG. 5, and FIG. 4 is a perspective view showing a partial cross-section of the internal structure of the shell-type transformer, FIG. 5 is a perspective view showing the inside of the upper tank portion as seen through, and FIG. 6 is a cross-sectional view of the upper tank portion.
In the figure, reference numeral 1 denotes a coil group, and a plurality of high voltage coils 1
a and a plurality of low voltage coils 1b are superimposed and arranged vertically. Reference numeral 2 denotes an iron core laminated on the center part and the outer peripheral part of the coil group 1. Reference numeral 3 denotes an insulating barrier arranged so as to surround a side of a portion protruding from the iron core of the coil group 1. Reference numeral 4 denotes a coil group 1 and the iron core 2. The lower tank 4
a, a middle tank 4b and an upper tank 4c.

Reference numeral 6 denotes a high-voltage connection lead for connecting the divided coils of the high-voltage coil 1a and connecting between bushings to be connected to the outside, and 7 to connect between the divided coils of the low-voltage coil 1b and connecting between the bushings to be connected to the outside. Low voltage connection leads,
Reference numeral 8 denotes a lead support for supporting the high-voltage lead 6 at a predetermined insulation distance from the inner wall of the tank 4, and is formed of an insulating material and includes a rod-shaped member 8a and a U-shaped member 8b. Reference numeral 9 denotes a pipe flange for connecting an insulating oil pipe for circulating the insulating oil filled in the tank 4 to a cooling device (not shown).

[0004] The shell-type transformer is configured such that the lower end of the coil group 1 is inserted into the lower tank 4a to be erected, and the core 2 is formed on the upper surface of the lower tank 4a so as to surround the center and periphery of the coil group 1.
And the middle tank 4 along the outer surface of the laminated iron core 2.
b, and the upper tank 4c is mounted above the middle tank 4b. Inside the upper tank 4c, the high-voltage coil 1a of the coil group 1 is disposed at a position where a predetermined insulation distance is maintained between the upper end of the low-voltage coil 1b and the lower surface of the ceiling, and the rod-shaped member 8a and the U-shaped It is connected by a high-voltage connection lead 6 held on the ceiling surface of the upper tank 4c while being held by a lead support 8 composed of a member 8b, and connected to a bushing (not shown) externally connected. The low-voltage coil 1b is connected to the upper end of the high-voltage coil 1a and the high-voltage connection lead by a low-voltage connection lead 7 disposed at a position that maintains a predetermined insulating distance between the high-voltage coil 1a and the side wall of the upper tank 4c. Connected to the bushing. The inside of the tank 4 is filled with insulating oil.

An oil-filled electric device such as a shell-type transformer is configured as described above, and the insulating oil filled therein rises inside the coil group 1 and is connected to a pipe flange attached to the upper tank 4c. 9 circulates to a cooling device (not shown) connected by an insulating oil pipe, is cooled, and circulates in a circulation system returning to the lower tank 4a. Oil-filled electrical equipment has coil group 1,
A predetermined insulation distance is maintained between the high-voltage connection lead 6, the low-voltage connection lead 7 and the inner wall of the tank 4 to ensure the dielectric strength, and the insulating oil filled therein is reduced as much as possible to reduce the overall weight. Designed. In the conventional oil-filled electric device of the shell-type transformer shown in FIG. 4, the upper surface of the upper tank 4c is flat, and there is a portion where the insulation distance from the high-voltage connection lead 6 is longer than necessary. The amount of insulating oil is large and the overall weight is heavy.

As a means for reducing the amount of insulating oil in the upper part of the tank, there is a method in which a lead duct is arranged above the upper tank 4c so as to reduce the amount of insulating oil, as shown in FIG. In this configuration, the height of the upper tank 4c is reduced, a high-voltage lead duct 6T for inserting the high-voltage connection lead 6 is disposed above the upper tank 4c, and the high-voltage connection lead 6 is inserted therein. In this example, although the amount of insulating oil is reduced, the upper tank 4c and the high-pressure lead duct 6T
It is necessary to connect with high accuracy, and there is a disadvantage that the number of parts increases.

[0007]

In the conventional oil-filled electric apparatus configured as described above, the upper tank 4c has the structure shown in FIGS.
And the tank ceiling is made of a flat plate as shown in Fig. 7, and there is a space that is not necessary for securing the insulation strength in addition to a portion necessary for insulating the high-voltage connection lead 6, and the amount of insulating oil to be filled And the tank ceiling is flat, so that the decomposition gas generated by the internal failure spreads over the entire surface of the ceiling of the upper tank 4c, and the detection sensitivity of the internal abnormality is deteriorated. There was a point. In addition, since the high-voltage connection lead 6 has a structure in which the high-voltage connection lead 6 is sandwiched and fixed between the rod-shaped member 8a and the U-shaped member 8b, the portion of the high-voltage connection lead 6 where the rod-shaped member 8a contacts easily deforms. There was also a problem that it could not be done.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the shape of the tank ceiling of oil-filled electric equipment is reduced by ensuring a necessary insulation distance from the high-voltage connection lead and reducing the amount of insulating oil. It is an object of the present invention to provide an oil-filled electrical device that has a reduced overall weight, has a good detection sensitivity to decomposed gas generated at the time of an internal failure, and can firmly support a high-pressure connection lead.

[0009]

According to a first aspect of the present invention, there is provided an oil-filled electric device, wherein a coil group in which a high-voltage coil and a low-voltage coil are laminated and an iron core are housed in a tank, and the high-voltage coil is an upper end of the low-voltage coil. The low-voltage coil is located at a position where a predetermined insulation distance can be secured with respect to the upper end of the high-voltage coil, the high-voltage connection lead, and the inner wall of the upper tank, respectively, with the high-voltage connection lead arranged at a position where a predetermined insulation distance can be secured. The tank ceiling is formed with a flat portion at a height that can secure an insulation distance corresponding to the surface potential of the low-voltage connection lead, and the portion of the tank ceiling facing the high-voltage connection lead is connected to the high-voltage connection lead. A semi-cylindrical projection is formed so that the inner surface is located at a position where an insulation distance corresponding to the surface potential of the lead can be secured.

According to a second aspect of the present invention, there is provided an oil-filled electrical device, wherein the protrusion provided on the flat portion of the tank ceiling of the first aspect is located at an insulation distance corresponding to the surface potential of the high voltage connection lead. It is formed in a circumscribed semi-polygonal cylindrical shape.

According to a third aspect of the present invention, there is provided an oil-filled electrical device, wherein the high voltage connection lead according to the first or second aspect has a support portion formed in a circular shape in accordance with the outer diameter of the high voltage connection lead. It is configured to be sandwiched by divided lead supports and supported on a flat part of the tank ceiling.

According to a fourth aspect of the present invention, there is provided an oil-filled electric apparatus having a configuration in which a pipe flange for connecting an insulating oil circulation pipe is attached to a protruding portion of a tank ceiling according to the first or second aspect.

According to a fifth aspect of the present invention, there is provided an oil-filled electrical apparatus having a gas detector attached to a top of a projecting portion of a tank ceiling according to the first or second aspect.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a perspective view showing the inside of an upper tank portion of a shell-type transformer, which is an oil-filled electric device according to Embodiment 1, and FIG. 2 is a sectional view of the upper tank portion. The structure below the upper tank is the same as the conventional structure, and the drawing is omitted. In the figure, the high-voltage coil 1a and low-voltage coil 1b of the coil group 1, the high-voltage connection lead 6, and the low-voltage connection lead 7 are the same as those in the conventional configuration. An upper tank 14 is provided with a semi-cylindrical projection 14T at a portion facing the flat portion 14a and the high voltage connection lead 6. 1
Reference numeral 8 denotes a lead support made of an insulating material,
8a, a semicircular supporting portion corresponding to the outer diameter of the high-voltage connecting lead 6 and a C-shaped tightening member 18
and b, so that the high-voltage connection lead 6 is sandwiched therebetween. 19a is a pipe flange for connecting a pipe for circulating insulating oil provided on the side of the upper tank 14, and 19b is a pipe flange for connecting the insulating oil provided on the protrusion 14T of the upper tank 14 to the high-voltage connection lead 6 and the low-pressure connection lead 7. It is a pipe flange for connecting a pipe for flowing to a part. Reference numeral 20 denotes a gas detector attached to the top of the protrusion 14T of the upper tank 14.

The upper tank portion of FIG. 1 is a conventional structure of FIG.
The high voltage connection lead 6 and the low voltage connection lead 7 cover the upper part of the state where the coil group 1 is connected to the middle tank portion in which the iron core 2 and the coil group 1 having the same structure as shown in FIG. The height of the flat portion 14a of the tank ceiling of the upper tank 14 is set to a height at which an insulation distance corresponding to the surface potential of the low-voltage connection lead 7 can be ensured. The inner surface of the semi-cylindrical projection 14T is formed at a position where an insulation distance corresponding to the surface potential of the connection lead 6 can be ensured.

An insulating oil pipe connected to a cooling device (not shown) is connected to the pipe flanges 19a and 19b, and an insulating oil pipe is connected between the cooling device and the lower tank 14a. An insulating oil circulation system is formed which rises inside the coil group 1 of the equipment and returns from the upper tank 14 through the cooling device to the lower part of the oil-filled electric equipment, and the insulating oil circulates in the circulation system during operation. Cooled. Piping flange 19 attached to the protruding portion 14T of the upper tank 14
An insulating oil pipe is also connected to b, so that the insulating oil is circulated in the high-pressure connection lead 6 and the low-pressure connection lead 7 so as to be cooled. A gas detector 20 for detecting a decomposition gas generated at the time of an internal failure is attached to the top of the projection 14T on the ceiling of the upper tank 14.

Since the upper portion of the oil-filled electric device is configured as shown in FIGS. 1 and 2, there is no space inside the upper tank 14 that does not contribute to the dielectric strength, and the amount of insulating oil inside the oil-filled electric device is reduced. Since the gas detector 20 is mounted on the top of the semi-cylindrical protrusion 14T which is higher than the flat portion 14a of the tank ceiling of the upper tank 14, the decomposition gas generated at the time of an internal failure is sensitive. Detection, and can appropriately respond to internal failure of oil-filled electrical equipment.
Reliability can be improved. Further, since the insulating oil is circulated also from the semi-cylindrical protrusion 14T of the upper tank 14, the cooling of the high-voltage connection lead 6 and the low-voltage connection lead 7 is improved. Further, a lead support 18 which is held so as to be in close contact with the outer diameter of the high voltage connection lead 6.
As a result, the high-voltage connection lead 6 is firmly supported without deformation, and insulation reliability is improved.

Embodiment 2 FIG. The second embodiment has a configuration in which the shape of the semi-cylindrical projection of the upper tank of the first embodiment is formed in a semi-polygonal cylindrical shape. The configuration is shown in FIG. In the figure, a coil group 1, a high-voltage connection lead 6, a low-voltage connection lead 7, a lead support 18, piping flanges 19a and 19b, and a gas detector 20 are the same as those in the first embodiment. An upper tank 24 has a portion facing the flat plate portion 24a and the high voltage connection lead 6 and a semi-polygonal cylindrical protrusion 24 circumscribing a position separated by an insulation distance corresponding to the surface potential of the high voltage connection lead 6.
It is formed in a shape provided with T.

Projection 2 of upper tank 24 of oil-filled electric equipment
When the 4T is formed in a semi-polygonal cylindrical shape as shown in FIG. 3, there is an advantage that the protrusion 24T can be easily manufactured by a method of cutting and welding a plate material. The amount of insulating oil inside other oil-filled electrical equipment is reduced, the weight can be reduced, the decomposition gas generated at the time of internal failure can be detected with high sensitivity, the cooling of the high-voltage connection lead 6 and the low-voltage connection lead 7 is improved, The effect that the high-voltage connection lead 6 is not deformed by the support by the lead support 18 that is held in close contact with the outer diameter of the connection lead 6 can be obtained as in the first embodiment.

[0020]

According to the first aspect of the present invention, there is provided an oil-filled electric device in which a coil group in which a high-voltage coil and a low-voltage coil are laminated and an iron core are housed in a tank, and the high-voltage coil is fixed to an upper end of the low-voltage coil. The low-voltage coil is connected to the upper end of the high-voltage coil, the high-voltage connection lead and the inner wall of the upper tank by a high-voltage connection lead arranged at a position where a predetermined insulation distance can be ensured. The tank ceiling is flat, and the tank ceiling has a flat portion at a height that can secure an insulation distance corresponding to the surface potential of the low-voltage connection lead. The portion of the tank ceiling facing the high-voltage connection lead is the surface potential of the high-voltage connection lead. The semi-cylindrical projection is formed so that the inner surface is located at a position where the insulation distance corresponding to There is no space that does not contribute to the edge strength, the less insulating oil of the internal oil-filled electrical device, weight reduction can be achieved.

According to a second aspect of the present invention, in the oil-filled electrical device, the protrusion provided on the flat portion of the tank ceiling according to the first aspect has an insulation distance corresponding to the surface potential of the high-voltage connection lead. Since it is formed in a semi-polygonal cylindrical shape circumscribing the position, the protrusion can be easily formed by welding a plate material, and there is no space inside the upper tank that does not contribute to the dielectric strength. The amount of insulating oil inside the device is reduced, and the weight can be reduced.

According to a third aspect of the present invention, there is provided an oil-filled electrical device, wherein the high-voltage connection lead according to the first or second aspect has a support portion formed in a circular shape in accordance with the outer shape of the high-voltage connection lead, and is divided into two parts. The high-voltage connection lead is not deformed, and the reliability of insulation is improved, since it is configured to be sandwiched by the provided lead support and supported on the flat portion of the tank ceiling.

According to a fourth aspect of the present invention, there is provided an oil-filled electric apparatus having a configuration in which a pipe flange for connecting an insulating oil circulation pipe is attached to a protruding portion of a tank ceiling according to the first or second aspect. The cooling of the high-voltage connection leads and the low-voltage connection leads is also improved.

The oil-filled electrical device according to claim 5 of the present invention has a configuration in which a gas detector is attached to the top of the protruding portion of the tank ceiling according to claim 1 or 2, so that an internal failure occurs. Decomposed gas can be detected with high sensitivity.

[Brief description of the drawings]

FIG. 1 is a perspective view in which the inside of an upper portion of an oil-filled electric device according to Embodiment 1 of the present invention is seen through.

FIG. 2 is a sectional view of an upper portion of the tank according to the first embodiment.

FIG. 3 is a sectional view of an upper portion of a tank according to a second embodiment.

FIG. 4 is a perspective view of a shell-type transformer which is a conventional oil-filled electric device.

FIG. 5 is a perspective view of the inside of an upper part of a shell-type transformer, which is a conventional oil-filled electric device, as seen through.

FIG. 6 is a cross-sectional view of an upper portion of a conventional oil-filled electric device.

FIG. 7 is a cross-sectional view of the upper part of another example of the conventional oil-filled electric device.

[Explanation of symbols]

1 coil group, 6 high-voltage connection lead, 7 low-voltage connection lead, 14 upper tank, 14T projection, 18 lead support, 19a, 19b piping flange, 20 gas detector, 24 upper tank, 24T projection.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mineho Kanda 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Mitsubishi Electric Corporation (reference) 5E050 CA03

Claims (5)

[Claims] A tank group includes a plurality of divided coil groups in which a high-voltage coil and a low-voltage coil are superimposed, and an iron core laminated around the coil group. The low-voltage coil is connected to the upper end of the high-voltage coil, the high-voltage connection lead and the inner wall of the upper tank by a high-voltage connection lead arranged at a position where a predetermined insulation distance can be secured. In an oil-filled electrical device connected by a lead and filled with insulating oil inside the tank, the tank ceiling is formed with a flat portion at a height at which an insulation distance corresponding to the surface potential of the low-voltage connection lead can be secured. The portion of the ceiling facing the high voltage connection lead is such that the inner surface is located at a position where an insulation distance corresponding to the surface potential of the high voltage connection lead can be secured. An oil-filled electric device characterized in that a semi-cylindrical protrusion is formed on the electric device. 2. A projection provided on a flat portion of a tank ceiling is formed in a semi-polygonal cylindrical shape circumscribing a position of an insulation distance corresponding to a surface potential of a high voltage connection lead. The oil-filled electrical device according to 1. 3. The high-voltage connection lead is characterized in that a support portion is formed in a circular shape corresponding to the outer diameter of the high-voltage connection lead, is sandwiched by two divided lead supports, and is supported on a flat portion of a tank ceiling. The oil-filled electric device according to claim 1 or 2, wherein 4. The oil-filled electrical device according to claim 1, wherein a pipe flange for connecting an insulating oil circulation pipe is attached to a protruding portion of the tank ceiling. 5. The oil-filled electric device according to claim 1, wherein a gas detector is attached to a top of the protruding portion of the tank ceiling.