JPH04355020A - Three-phase collective type vacuum breaker - Google Patents

Abstract

PURPOSE:To directly implant a through bushing in a closed vessel while eliminating necessity for a shielding cover by constitution of the single closed vessel relating to a 3-phase breaker main unit. CONSTITUTION:A 3-phase vacuum valve 3 and a connecting mechanism 29 are collectively housed in a closed vessel 22 of rectangular parallelopiped sealed with insulating gas 9. Operating force generated in an operating device 12 is transmitted through a drive rod 28, mechanism 29 and an insulation rod 18 to perform action of opening/closing the valve 3. In the vessel 22, the first through bushings 5a, 5b of three phase, provided with the first conductor 25a connected to this vessel, provided. By constituting this closed vessel of a single quantity, necessity of a cover for shielding the connecting mechanism from wind and rain is eliminated, in a 3-phase breaker main unit, and the through bushing can be directly implanted in the closed vessel to improve reliability by simplifying constitution.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-phase vacuum circuit breaker used in power circuits such as transmission lines and substations.

0002

2. Description of the Related Art Vacuum circuit breakers are widely used because of their excellent breaking performance and high reliability. In addition, each phase of the vacuum valve, which serves as a current cutoff point, is housed in a cylindrical grounded container filled with an insulating gas such as SF6 gas, and the vacuum is responsible for current cutoff and insulation inside the vacuum valve. A tank-type vacuum circuit breaker is used, which uses an insulating gas to perform creeping insulation and is more compact. FIG. 3 shows an example of the overall structure of a conventional three-phase tank-type vacuum circuit breaker, and FIG. 4 shows a cross-sectional structure of one phase of the circuit breaker body 1 shown in FIG. 3. In FIGS. 3 and 4, 2 is a closed container having a cylindrical cross section, and 3 is a vacuum valve, which is fixed to the closed container 2 which is at ground potential by an insulating spacer 4 while maintaining insulation. Reference numeral 5a denotes a first through bushing, which is fixed to a first branch pipe section 6a implanted at one end of the closed container 2. 7a is a terminal block connected to an external electric wire 8a, and an insulating gas 9 sealed in the first through bushing 5a and the airtight container 2 is connected to the upper end of the first through bushing 5a.
It is connected to a first conductor 10a that passes through the first through bushing 5a and is electrically connected to one end of the vacuum valve 3. The branch pipe section 6 of the closed container 2
At the end opposite to a, there is a second branch pipe part 6b, which has a terminal block 7b connected to an external electric wire 8b, a second conductor 10b, a second through bushing 5b
is installed. As the insulating gas 9, it is appropriate to use a medium having high insulating performance such as SF6, which is filled in the closed container 2 and the first and second through bushings 5a and 5b all at once. Although FIG. 4 shows the structure of only one phase of the circuit breaker main body 1, the other two phases also have substantially the same structure. Reference numeral 11 denotes a gas pipe that communicates the insulating gas 9 of the three-phase hermetic container 2. That is, in order to economically monitor the insulating gas 9, the three-phase insulating gas 9 is shared by the gas pipe 11.

Reference numeral 12 denotes an operating device for opening and closing the circuit breaker, which is mounted on a pedestal 13. A driving rod 14 connects the operating device 12 and the first phase of the circuit breaker main body 1 and transmits the operating force generated by the operating device 12. Reference numeral 15 denotes a connecting mechanism, and rods 16a and 16b connect the first phase and second phase of the circuit breaker body 1, and the second phase and third phase of the circuit breaker body 1, respectively.
, a lever 17 for changing the direction of the operating force, and the like. 18 is an insulating rod that insulates between the lever 17 and the vacuum valve 3, and also includes the driving rod 15, the rod 16a,
16b is transmitted to the vacuum valve 3. Insulating gas 9
is rotatably sealed from the atmosphere by a sealing device 19 provided on the lever 17. A cover 20 shields the drive rod 15, rods 16a, 16b, etc. from wind and rain. This circuit breaker is a three-phase tank-type vacuum circuit breaker in which the three-phase circuit breaker main body 1 is operated all at once by an operating device 12.

0004

SUMMARY OF THE INVENTION An object of the present invention is to provide a three-phase vacuum circuit breaker which solves the following problems in conventional equipment. (1) A three-phase tank-type vacuum circuit breaker combined with conventional gas insulation has each of the three phases housed in an independent cylindrical sealed container, so it connects not only the sealed container part but also the three phases. Storage items such as covers are required to shield connecting mechanisms such as rods and levers from wind and rain, and branch pipes are required to install insulated pipes approximately perpendicular to the cylindrical airtight container. It is expensive because it has a large number of parts and a complicated structure. (2) The number of parts and gas seals are large, and there are many factors that reduce reliability. (3) The main body of the shutoff gas is installed in a gas atmosphere, which is a stable atmosphere that is not affected by the external environment, and there is little deterioration over time. Although it is shielded from the wind and rain by the cover, it is installed in an atmosphere that communicates with the atmosphere, so it is unavoidable that, for example, due to humidity, rust will develop over time and deterioration will progress. (4) Gas piping that connects each sealed container tends to be a weak point in terms of strength.

[0005]

[Means for solving the problem] A rectangular parallelepiped sealed container,
an insulating gas sealed in the airtight container; a three-phase vacuum valve installed at a predetermined distance within the airtight container; and a three-phase vacuum valve at one end of the upper surface of the airtight container. A three-phase first through bushing equipped with a first conductor that communicates between the inside and outside of the closed container, installed at a corresponding position, and installed at the end of the top surface of the closed container on the opposite side from the first through bushing. A three-phase second through-bushing is provided with a second conductor that communicates between the inside and outside of the sealed container. A connecting mechanism for connecting the three-phase circuit breaker bodies and transmitting operating force is arranged in the sealed container.

[0006]

[Operation] According to the invention configured as described above, one sealed container can be configured for each three-phase circuit breaker body, and the connecting mechanism connecting the three-phase circuit breaker bodies can be This eliminates the need for a cover to shield the connection mechanism from air, and the coupling mechanism is installed in an insulating gas, a stable atmosphere that is not affected by outside air. Furthermore, since the through bushing can be directly implanted into the closed container, the number of parts and gas sealing locations are reduced. Furthermore, gas piping connecting the three phases becomes unnecessary.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall structure of a three-phase vacuum circuit breaker according to the present invention, and FIG. 2 shows a cross-sectional structure of one phase of the circuit breaker body 21 shown in FIG. Parts that are the same as those of the conventional product shown in FIGS. 3 and 4 are given the same numbers for convenience of reference. In FIGS. 1 and 2, 22 is a rectangular parallelepiped hexahedral sealed container, 3 is a vacuum valve, and the three phases are separated by a predetermined interval, and the ground potential is set parallel to the bottom surface of the sealed container 22 by an insulating spacer 23. It is fixed to the closed container 22 while maintaining insulation. Reference numeral 5a denotes a first through bushing, which is fixed at one end 24a of the upper surface of the closed container 22 at a position corresponding to the vacuum valve 3. 7a is a terminal block connected to an external electric wire 8a, and at the upper end of the first through bushing 5a, the insulating gas 9 sealed in the first through bushing 5a and the sealed container 22 is sealed, and the first through bushing 5a is sealed. Penetration bushing 5a
A first penetrating the inside of the vacuum valve and electrically connecting with one end of the vacuum valve 3.
is connected to the conductor 25a. At the end 24b of the airtight container 22 opposite to the end 24a, a terminal block 7b connected to the external electric wire 8b, a second conductor 25b, and a second through bushing 5b are installed, similarly to the end 24a side. has been done. In this structure, the first and second through bushings 5a
, 5b are installed, so that the sealing of the airtight container 22 is not impaired even when a fastening material 26 such as a bolt used for fixing the first and second through bushings 5a, 5b is attached. Therefore, the airtight container 22 may be made of a thicker material, or the ends 24a, 2
The structure is extremely simple, as it is only necessary to add the flange 27 to the portion 4b. Although FIG. 2 shows the structure of only one phase of the circuit breaker main body 21, the other two phases also have substantially the same structure. Since the vacuum valve 3 is arranged parallel to the bottom of the sealed container 22, the three-phase structure is almost the same, so the insulating spacer 23, first and second conductors 25a, 25b, etc. are unified and manufactured. It has the advantage of being easy to do. Furthermore, connection for collectively operating the three-phase circuit breaker main body 21 is easy. Easy production means economic efficiency,
This is convenient for providing highly reliable equipment.

Reference numeral 12 denotes an operating device for opening and closing the circuit breaker, which is mounted on a pedestal 13. Reference numeral 28 denotes a drive rod, which is located on the atmospheric side and connects the operating device 12 and the first phase of the circuit breaker main body 21, and transmits the operating force generated by the operating device 12. 29 is a connecting mechanism located in the insulating gas 9, and the circuit breaker body 21
It is comprised of rods 16a and 16b that respectively connect the first and second phases of the circuit breaker body 21 and the second and third phases of the circuit breaker body 21, a lever 17 that changes the direction of the operating force, and the like. 18 is an insulating rod that insulates between the lever 17 and the vacuum valve 3 and transmits the operating force of the drive rod 28 and the rods 16a and 16b to the vacuum valve 3. Insulating gas 9 is connected to drive rod 2
8 and a sealing device 31 provided on the connecting shaft 30 of the connecting mechanism 29.
It is rotatably sealed from the atmosphere side. In other words, everything from the sealing device 31 to the circuit breaker main body 21 side is installed in the insulating gas 9, and has a structure that is not affected by the outside air. This circuit breaker is a three-phase vacuum circuit breaker in which three-phase circuit breaker main bodies 21 are operated simultaneously by an operating device 12. Although the drive rod 28 has been described as being in the atmosphere, it may be provided with a cover to shield it from wind and rain. It is also possible to configure the drive rod 28 integrally with the operating device 12. The shielding cover of the drive rod 28 can be set arbitrarily according to design conditions. However, the shielding cover is not related to the present invention.

Now, the insulating gas 9 filling the inside of the closed container 22 and the first and second through bushings 5a and 5b is as follows.
Gases with high insulation performance such as SF6 are effective in making circuit breakers more compact, but in the case of non-uniform electric field structures,
It is known that a gas mixture of approximately 90% SF6 and approximately 10% dry air or nitrogen has better insulating properties than pure SF6 gas. (For example, electronic journal, 1st
(Vol. 07, No. 2, '87) The vacuum circuit breaker of the present invention houses a three-phase vacuum valve 3 in a rectangular parallelepiped sealed container 22, and has a concentric circular structure with an equal electric field design. Compared to the conventional vacuum circuit breakers shown in Figs. 3 and 4, which use a simple cylindrical container, it is difficult to create an equal electric field structure, so the above-mentioned approximately 90% SF6 and approximately 10% dryness is required. By using a mixed gas of air or nitrogen, a three-phase vacuum circuit breaker with even better insulation performance can be obtained.

[0010] Furthermore, these pure SF6 and SF6
Since the insulating gas 9 such as the mixed gas has high insulating performance, sufficient insulation on the outer surface of the vacuum valve 3 can be ensured even at low pressure. On the other hand, a closed container 2 composed of six flat surfaces
No. 2 is not suitable for use under high pressure because bending stress acts on the plane due to pressure and bending is likely to occur. If the container is cylindrical, stress due to internal pressure becomes tensile stress and deformation is slight. As a result, it is desirable that the insulating gas 9 sealed in the airtight container 22, which has a planar structure like a rectangular parallelepiped, has a low pressure. In this case, the pressure is 2kgf
/cm2 or less, the structure becomes a highly safe low-pressure structure that is not subject to the pressure vessel structural standards according to the Ministry of Labor's notification.

[0011] Also, the inside of the sealed container 22 is vacuumed, that is, the pressure inside the sealed container 22 is -1 kgf/cm2 with respect to the external pressure of 0 kgf/cm2, and the pressure difference between the inside and outside of the sealed container 22 is set to 1 kgf/cm2, and then the sealed container 22 is sealed. When filling the container 22 with the insulating gas 9, if the maximum working pressure of the insulating gas 9 is set to 1 kgf/cm2, the direction in which the pressure acts will differ between the internal pressure and the external pressure that acts on the sealed container 22 when vacuumed. Even if there is a difference in
This is the most economical design in terms of strength design. Maximum working pressure is 1k
gf/cm2, if the upper limit of the operating temperature is applied to the IEEJ Electrical Standards Committee standard JEC-2300-1985, which is a typical standard applied to circuit breakers, in the case of silver connections, contact The temperature rise limit of the unit is 65 degrees, and when combined with the upper limit of the ambient temperature of 40 degrees Celsius, a total of 105 degrees Celsius is obtained. Practically speaking, the temperature of the insulating gas 9 does not rise as much as the contact area, so if the temperature of the insulating gas 9 rises by 20 to 60°C,
〜100℃, assuming the reference temperature is 20℃, absolute pressure is proportional to absolute temperature, so the normal pressure P is P
=2×(273+20)/{273+(60~100)
}-1=0.76 to 0.57 kgf/cm2. From this, the normal pressure at 20℃ is 0.8 to 0.5
If it is set within the range of kgf/cm2, the most economical design of the airtight container 22 is possible.

0012

[Effects of the invention] Only one sealed container is required for each three-phase vacuum valve, so it can be configured with fewer parts, and there is no need for a cover to shield the connection mechanism that connects the three-phase circuit breaker bodies from wind and rain. Become. Furthermore, the structure is simple because the through bushing can be directly planted in the closed container. Therefore, it can be manufactured in a short period of time and is economical. In addition, as the number of parts is reduced, the number of gas sealing points is also reduced, which reduces the number of gas leakage factors and improves reliability. Furthermore, there is no need for gas piping to connect the three phases, making it even more economical and eliminating weak points in terms of strength.

[Brief explanation of drawings]

FIG. 1 is an overall structural diagram of a three-phase vacuum circuit breaker of the present invention.

FIG. 2 is a cross-sectional structural diagram of the main body portion of the three-phase vacuum circuit breaker of the present invention.

FIG. 3 is an example of the overall structure of a conventional three-phase tank-type vacuum circuit breaker.

FIG. 4 is an example of a cross-sectional structural diagram of a main body portion of a conventional three-phase tank-type vacuum circuit breaker.

[Explanation of symbols]

3 Vacuum valve 5a First through bushing 5b Second through bushing 9 Insulating gas 12 Operation device 18 Insulating rod 21 Breaker body 22 Sealed container 23 Insulating spacer 25a First conductor 25b Second conductor 28 Driving rod 29 Connecting mechanism 31 Sealing device

Claims (1)

[Claims] 1. A rectangular parallelepiped sealed container, an insulating gas sealed in the sealed container, a three-phase vacuum valve fixed at a predetermined distance in the sealed container via an insulating spacer, and the sealed container. A three-phase first vacuum valve is provided with a first conductor that communicates between the inside and outside of the sealed container, which is installed at one end of the top surface at a position corresponding to the three-phase vacuum valve with a predetermined space apart. A three-phase second through bushing including a through bushing and a second conductor installed at the end of the upper surface of the closed container opposite to the first through bushing and communicating between the inside and outside of the closed container, The connection mechanism that connects each of the three phases from the first through-through bushing side to the second through-through bushing side via the vacuum valve, and connects the three-phase circuit breaker bodies and transmits the operating force is connected to the above-mentioned sealing mechanism. A three-phase bulk vacuum circuit breaker characterized by being placed inside a container.