JPS598273Y2 - Vacuum cutter - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a vacuum breaker.

The voltage of vacuum breakers continues to increase, and currently 84
KV class voltages have appeared, and ultra-high voltage voltages are on the way.

Figure 1 shows the current 84 KV class vacuum breaker.

In the figure, 1 and 2 are insulating cylinders 6 and 7 connected at one end through connection rings 3 and 4 and an intermediate ring 5, respectively.
A fixed side end plate and a movable side end plate are attached to the other ends of the insulating cylinders 1 and 2 via connecting rings 8 and 9, respectively, and these members form a vacuum container.

10 is a fixed lead rod inserted into the fixed end plate 6; 11 is a movable lead rod inserted into the movable end plate 7 and connected to the movable end plate 7 via the bellows 12; 13.14
are a fixed electrode and a movable electrode attached to the tip of each lead rod 10.11 so as to face each other, and each electrode 13
．． 14 has contact electrode portions 13 a and 14 a that are in contact with the opposing electrode in a manner that allows them to move toward and away from each other, and coil electrode portions 13 b and 14 b that generate an axial magnetic field when energized.

15 is a main shield attached to the intermediate ring 5 so as to surround both electrodes 13.14, and 16.17 is a cylindrical shield supporting insulator attached at one end to the end plates 6 and 7 via connecting rings 18.19. 20.21 are intermediate shields each attached to the shield support insulator 16.17 via a connecting ring 22.23, and the intermediate shield 20.21 is connected between the main shield 15 and each electrode 13.14, respectively. and surrounding each electrode 13, 14 respectively.

Further, 24 and 25 are shaft shields and bellows shields attached to each lead rod 10 and 11, respectively, and 26 and 27 are outer shields attached to end plates 6 and 7, respectively.

In addition, 13 C and 14 C are contact electrode parts 13 a, respectively.
, 14a and the coil electrode parts 13b, 14b, and 13d, 14d are the contact electrode parts 1, respectively.
These are connecting conductors provided between 3 a and 14 a and the coil electrode portions 13 b and 14 b.

When the vacuum breaker is cut off, the movable lead rod 11 is moved downward by an operating device (not shown), and both electrodes 13, 14 are
Open as shown.

At this time, an arc is generated between both electrodes 13, 14, but this arc is captured by the axial magnetic field generated by each coil electrode portion 13b, 14b, and is connected to each contact electrode portion 13a.
, 14 a, and is confined therebetween.

Therefore, due to arc concentration, each contact electrode portion 13a,
14a is prevented from generating a large amount of metal vapor, and the shutoff ability is improved.

Further, each vacuum gap formed by providing each shield, in particular a main shield 15 at an intermediate potential and each intermediate shield 20.21 having a potential approximately intermediate between the main shield 15 and each electrode 13.14, is provided with an electrode 13. By sharing the voltage between .

However, it is desired that the vacuum breaker has an even higher voltage and an increased breaking current, and in that case, the electrodes 13, 14
Disadvantages such as an increase in the gap between the electrodes 13 and each shield, an increase in the size of the vacuum vessel, and an increase in price occur.In particular, if the gap between the electrodes 13 and 14 becomes long, the magnetic flux distribution of the axial magnetic field between the gaps will be affected. This has the disadvantage that distortion occurs and the magnetic flux density decreases, resulting in a decrease in the arc trapping ability of the axial magnetic field and a decrease in the interrupting ability.

The present invention eliminates the above-mentioned drawbacks, prevents the inter-electrode gap from becoming longer by improving the withstand voltage of the inter-electrode gap, and allows the axial magnetic field to effectively act on the arc. The purpose of the present invention is to provide a vacuum breaker capable of interrupting current.

Embodiments of the present invention will be described below with reference to the drawings.

Components that are the same as those in the prior art are designated by the same reference numerals, and explanations thereof will be omitted.

In this embodiment, each shield 15 is
, 20, 21. 24 to 27, and the surfaces of the electrodes 13 and 14 (excluding the arc generating side of the contact electrode parts 13 a and 14 a).

) is formed with a thin layer 28 (about 2 to 30 μm thick) of metal such as beryllium Be, boron B, or carbon (graphite) C by means of plating, vapor deposition, or the like.

These metals are lighter and harder than copper and iron-based metals, and their melting and boiling points are the same or higher.

In addition, these metals have a secondary electron emission coefficient (number of radiated secondary electrons/number of human irradiated primary electrons) δ<1, and they emit electrons, ions, X-rays, photons, waves, etc. generated when voltage is applied or current is cut off. absorb the energy of

Therefore, the withstand voltage between each shield and each electrode 13, 14 is improved.

For example, when a thin layer of Be is used as the thin metal layer 28, the withstand voltage is about 1.5 compared to the case where the thin layer 28 is not provided.
It was improved by ~2.5 times.

In particular, the potential distribution between the electrodes 13.14 is improved by improving the withstand voltage between the main shield 15 surrounding the electrode 13.14 and the intermediate shields 20, 21, especially between the intermediate shields 20.21. The withstand voltage is improved.

Therefore, the gap between the electrodes 13 and 14 does not become large even in a vacuum breaker for ultra-high voltage and large current circuit breakers.

Therefore, since no distortion occurs in the magnetic flux distribution of the axial magnetic field generated by each coil electrode portion 13b, 14b, the magnetic flux density does not decrease, the axial magnetic field is effectively applied to the arc, and the breaking ability is improved.

In the above embodiment, the shield has a so-called multiple structure, but it does not necessarily have to have a multiple structure.

Alternatively, a thin layer 28 may be provided over the entire surface of each shield.

As described above, in the present invention, each electrode is provided with a coil electrode part that generates an axial magnetic field, and the arc generated at the time of disconnection is captured by the axial magnetic field and distributed uniformly on the electrode, so that the arc is concentrated. A large amount of metal vapor is not generated, and the cutting ability is improved.

In addition, electrons such as Be, X-rays,
It has a thin layer of metal that absorbs energy such as photons and waves, which improves the withstand voltage of this shield, which improves the potential distribution between the electrodes and increases the withstand voltage between the electrodes, increasing the breaking ability. improves.

Furthermore, due to the improvement in the withstand voltage between the electrodes, the gap between the electrodes does not become large even in a vacuum breaker for ultra-high voltage and large current interruption, so that no distortion occurs in the axial magnetic field and the magnetic flux density does not decrease.

Therefore, the axial magnetic field is effectively applied to the arc, and the breaking ability does not deteriorate due to the lengthening of the gap between the electrodes.

Further, it also becomes possible to downsize the device. Furthermore, since the axial magnetic field is effectively applied to the arc, the arc is confined between the electrodes,
The thin metal layer provided on the surface of the shield does not melt due to the arc, and a stable withstand voltage can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view of a conventional vacuum breaker, and FIG. 2 is a longitudinal sectional front view of a vacuum breaker according to the present invention. 1, 2... Insulation tube, 3, 4, 8, 9, 18, 1
9, 22, 23... Connection ring, 5...
・Intermediate ring, 6, 7...End plate, 10...
・・Fixed lead rod, 11 ・・・・Movable lead rod, 1
2... Bellows, 13... Fixed electrode,
14...Movable electrode, 13a, 14a...
・Contact electrode part, 13b, 14b... Coil electrode part, 15... Main shield, 16.17...
...Shield supporting insulator, 20.21...Intermediate shield, 28...Thin layer of metal.

Claims (1)

[Scope of utility model registration request] A pair of electrodes each having a coil electrode portion that generates an axial magnetic field in a vacuum container are arranged facing each other so as to be able to come into contact with and separate from them, and a thin layer of beryllium, boron, or graphite is formed on the surface of a shield provided to surround the electrodes. A vacuum breaker characterized by: