JPH04349321A - Three phase package type vacuum circuit breaker - Google Patents

Abstract

PURPOSE:To make a simple structure and improve economy and reliability by connecting a three phase from a first through-bushing to a second through- bushing respectively through a three phase vacuum valve, and making insulation gas have a prescribed characteristic. CONSTITUTION:Insulation gas 9 is sealed into a rectangular parallelepiped sealed vessel 22, in which three phase vacuum valves 3 are installed at prescribed intervals. At positions facing the respective valves 3 at one end of the upper face of the vessel 22, three phase first through-bushings 5a are installed which are respectively fitted with first conductors 25a communicating the inside of the vessel 22 with the outside. At the other end of the upper face of the vessel 22 on the opposite side to the bushings 5a, three phase second through-bushings 5b are installed which are respectively fitted with second conductors 25b communicating the inside of the vessel 22 with the outside. The three phase first through-bushings 5a are then connected to the bushings 5b respectively through the valves 3, and the gas 9 is pressurized at a maximum pressure of 2kgf/cm<2> or lower. This enables a vacuum circuit breaker to consist of fewer members in a simple structure and to improve in economy and reliability.

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. 14 is a drive mechanism;
A drive rod 15 that connects the operating device 12 and the first phase of the circuit breaker body 1, a rod 16a that connects the first and second phases of the circuit breaker body 1, and the second and third phases of the circuit breaker body 1, respectively. ,
16b, a lever 17 for changing the direction of the operating force, and the like. 18 is an insulated rod that connects lever 17 and vacuum valve 3.
Insulating between the drive rod 15 and the rod 1
The operating forces of 6a and 16b are transmitted to the vacuum valve 3. The insulating gas 9 is rotatably sealed from the atmosphere by a sealing device 19 provided at the lever 17 portion. 20 is the drive rod 1
5, the 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 a large number of parts because each of the three phases is housed in an independent cylindrical sealed container. The structure is complicated and expensive, as it requires a branch pipe section for installing the insulator pipe so as to be approximately perpendicular to the pipe. (2) The number of parts and gas seals are large, and there are many factors that reduce reliability. (3) Gas piping that connects each sealed container tends to be a weak point in terms of strength.

[0005]

[Means for Solving the Problems] In the invention of claim 1, there is provided a rectangular parallelepiped sealed container, an insulating gas sealed in the sealed container, and a three-phase gas installed at a predetermined interval in the sealed container. a three-phase vacuum valve, and a first conductor that communicates between the inside and outside of the sealed container, which is installed at one end of the top surface of the sealed container at a position corresponding to each of the three-phase vacuum valves. a three-phase second through bushing that is installed at the end of the upper surface of the closed container on the opposite side of the first through bushing and is equipped with a second conductor that communicates between the inside and outside of the closed container. , the three phases are connected from the first through bushing side to the second through bushing side via the vacuum valve. In the invention of claim 2, in the invention of claim 1, the maximum pressure of the insulating gas is 2 kgf.
/cm2 or less. In the invention of claim 3, in the invention of claim 1, the maximum pressure of the insulating gas is 1 kgf.
/cm2. In the invention of claim 4, in the invention of claim 1, 2 or 3, the insulating gas is approximately 90%
of SF6 and approximately 10% dry air or nitrogen.

[0006]

According to the invention constructed as described above, only one sealed container can be provided for the three-phase circuit breaker main body. 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. According to the invention of claim 2, in addition to the effect of the invention of claim 1, a highly safe sealed container that is not subject to pressure vessel structural standards can be applied. According to the invention of claim 3, in addition to the effect of the invention of claim 1, the most economical design of the airtight container is possible. According to the invention of claim 4, in addition to the effects of the invention of claims 1, 2, or 3, by applying a mixture of approximately 90% SF6 and approximately 10% dry air or nitrogen, It becomes possible to provide a circuit breaker with better insulation properties than pure SF6 gas.

[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. 28 is a drive mechanism;
A drive rod 29 that connects the operating device 12 and the first phase of the circuit breaker body 21, a rod 1 that connects the first and second phases of the circuit breaker body 21, and the second and third phases of the circuit breaker body 21, respectively.
6a, 16b, 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 transmits the operating force of the drive rod 29 and the rods 16a and 16b to the vacuum valve 3. The insulating gas 9 is rotatably sealed from the atmosphere by a sealing device 19 provided at the lever 17 portion. 30 is a cover that shields the drive rod 29, rods 16a, 16b, etc. from wind and rain. 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.

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,
If the temperature reaches ~100℃, the reference temperature is 20℃, and absolute pressure is proportional to absolute temperature, so the normal pressure P is P=2×(273+20)/{273+(60~1
00)}-1 =0.76~0.57kgf/c
Get m2. Therefore, if the normal pressure at 20° C. is set in the range of 0.8 to 0.5 kgf/cm 2 , the most economical design of the closed container 22 is possible.

0012

Effects of the Invention: Since only one sealed container is required for each three-phase vacuum valve, it can be constructed with fewer members. 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 the drawing]

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 19 Sealing device 21 Breaker body 22 Sealed container 23 Insulating spacer 25a First conductor 25b Second conductor 28 Drive mechanism

Claims (4)

[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, A three-phase vacuum circuit breaker characterized in that each of three phases is connected from a first through-through bushing side to a second through-through bushing side via a vacuum valve. [Claim 2] The maximum working pressure of the insulating gas is 2 kgf.
2. The three-phase vacuum circuit breaker according to claim 1, wherein the vacuum is less than /cm2. [Claim 3] The maximum working pressure of the insulating gas is approximately 1k.
2. The three-phase vacuum circuit breaker according to claim 1, wherein the three-phase vacuum circuit breaker is gf/cm2. 4. The three-phase integrated type according to claim 1, wherein the insulating gas is composed of a mixture of approximately 90% SF6 and approximately 10% dry air or nitrogen. Vacuum circuit breaker.