JPS6310855B2 - - Google Patents

Description

[Detailed description of the invention] TECHNICAL FIELD The present invention relates to a vacuum shield disconnector.

In general, a vacuum shield disconnector is constructed by arranging a fixed electrode and a movable electrode facing each other in a vacuum container, and by bringing the movable electrode into contact with and separating from the fixed electrode, current can be applied.
We are making a decision. However, in the event of a break, an arc is generated between the electrodes, and if the break current is large, this arc receives an electromagnetic force in the direction of the electrode's outer circumference due to the interaction between the magnetic field generated by the arc itself and the magnetic field created by the external circuit. The arc is concentrated near the outer periphery of the electrode and locally heats that area, generating a large amount of metal vapor and reducing the shearing ability.

Conventionally, as a countermeasure against this problem, applying an axial magnetic field to the arc has been carried out. An example is shown in FIG. In the figure, 1 is an insulating cylinder, 2 and 3 are end plates attached to both ends of the insulating cylinder 1, and these members form a vacuum container. 4 is a fixed electrode attached to the end plate 2 via a fixed electrode rod 5; 6 is a movable electrode inserted through the end plate 3 and movably attached to the end plate 3 via a bellows 7; 8 is a movable electrode; A movable electrode is attached to a movable electrode rod 6, and the movable electrode 8 is arranged to face the fixed electrode 4. Further, the movable electrode 8 is attached to the movable electrode rod 6 and extends into a coil shape, and is attached to the coil electrode section 9 via a high-resistance material 10, and is electrically connected to the coil electrode section 9 via a connecting conductor 11. Similarly, the fixed electrode 4 is composed of a coil electrode part 13, a high resistance material 14, a connecting conductor 15, and a contact electrode part 16. With this structure of vacuum shield disconnector, each coil electrode part 9,
The current flowing through the electrodes 13 generates an axial magnetic field, and the electrons and ions carrying the arc current are captured by this magnetic field, preventing the arc from concentrating, and each contact electrode part 12, 16 is locally heated and a large amount of metal is generated. Steam is no longer generated and the shearing ability is improved. However, current flows through each coil electrode part 9, 13 even in the closed state, and each coil electrode part 9, 1
No. 3 has a long current path and large heat loss, so there are disadvantages such as temperature rise in vacuum shields and disconnectors for large rated currents.

For this reason, in the past, the electrode was further divided into two areas: the contact electrode part in the center and the arc diffusion electrode part on the outer periphery, and during normal energization, current flowed only to the contact electrode part, and the coil electrode part connected to the arc diffusion electrode part. Temperature rise is suppressed by preventing current from flowing through. However, in this case, it takes time for the arc generated at the contact electrode to move to the outer arc diffusion electrode when the shield is broken, and during that time, no axial magnetic field is generated, so the arc is concentrated at the contact electrode. This caused melting and evaporation due to localized heating, reducing the shearing performance.

The present invention eliminates the above-mentioned drawbacks and can not only reduce the temperature rise due to heat loss in a vacuum shield disconnector having a coil electrode section that generates an axial magnetic field, but also generates an axial magnetic field from the initial stage of the shear fracture. This can prevent arc concentration, and can also smooth the transition of the arc from the contact electrode section to the arc diffusion electrode section, as well as make the distribution of the axial magnetic field uniform in the transition process, thereby reducing the arc concentration. The purpose of the present invention is to provide a vacuum breaker and disconnector whose performance can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
2A to 2C show a first embodiment of the present invention, 1
Reference numeral 6 denotes an electrode rod; 17 denotes a small-diameter coil electrode portion consisting of a base 17a attached to the tip of the electrode rod 16 and each coil portion 17b extending 1/4 circumference from the base 17a in a coil shape; One of the connection conductors 18 is attached to each hole 17c provided at the tip, and a contact electrode part 19 is attached to the other end of each connection conductor 18.
Install. There is a recess 19 in the center of the contact electrode part 19.
Provide a. 20 is the base portion 17a and the contact electrode portion 19
A high resistance spacer made of stainless steel or ceramic is provided between the coil electrode part 17, the connection conductor 18, the contact electrode part 19 and the high resistance spacer 20.
form. 22 is a hole 22b provided in the base 22a.
is a large-diameter coil electrode portion having a coil portion 22c that is fitted and fixed to the tip of the electrode rod 16 and extends in a coil shape from the base portion 22a, and the extending direction of the coil portion 22c is opposite to the extending direction of the coil portion 17b. . In addition, a hole 22d provided at the tip of the coil portion 22c
Attach one end of the connecting conductor 23 to the
On the other end, an arc diffusion electrode part 25 is disposed concentrically around the outer periphery of the contact electrode part 19 with a gap 24 in between.
Install. 26 is a high-resistance spacer made of stainless steel or ceramic provided between the coil portion 22c and the arc diffusion electrode portion 25, and 22e is a hole for mounting the high-resistance spacer 26. Note that the fixed electrode and the movable electrode have the same shape.

In the above-mentioned vacuum shield disconnector, during normal energization, current flows from the electrode rod 16 to the base 17a of the coil electrode section 17.
The flow is divided into each coil portion 17b through the connection conductor 18.
It flows to the contact electrode part 19 via the , and flows to the counter electrode. In this way, current flows through the small-diameter coil electrode portion 17 even during normal energization, but the small-diameter coil electrode portion 17
Since the length of b is short, the temperature rise is small. In addition, at the initial stage of the shearing, the current flows along the same path as when normally energized, and due to the presence of the recess 19a, an arc is generated between the peripheral parts of the contact electrode part 19. The generated axial magnetic field is added to prevent the arc from concentrating. This axial magnetic field is relatively small because the coil electrode portion 17 is of a shunt type. Eventually, the arc moves beyond the gap 24 to the arc diffusion electrode section 25 due to the electromagnetic force and the diffusion force. Therefore, the current flows through the coil electrode section 22 and decreases.
An axial magnetic field is generated, and the concentration of the arc is also prevented in the arc diffusion electrode section 25, and the arc is eventually extinguished. The axial magnetic field generated in the coil electrode section 22 is larger than the axial magnetic field generated in the coil electrode section 17 because the coil electrode section 22 has a one-turn shape, and is opposite in direction.

In this manner, in the above-mentioned vacuum shield and disconnector, during normal energization, no current flows through the coil electrode portion 22, which has a large diameter and a long length of the coil portion 22c, so that the temperature rise is small. In addition, even immediately after the shear is broken, the axial magnetic field generated by the coil electrode section 17 is applied to the arc, so the arc does not concentrate at the contact electrode section 19, and melting due to local heating does not occur, improving the shear breaking ability. be able to. Furthermore, since the axial magnetic field generated in the coil electrode section 17 is relatively weak and the recess 19a is provided, the transition of the arc from the contact electrode section 19 to the arc diffusion electrode section 25 is accelerated.
Furthermore, during the arc transition process, both the coil electrode parts 17 and 22 generate an axial magnetic field, and this state is shown on the right side of FIG. 3 with the respective magnetic flux densities being A and B. In this case, the magnetic flux densities A and B are A<B and the directions are opposite, so A+B
Since the magnetic flux density distribution is as shown in the figure and averaged over the whole, arc concentration does not occur in either the contact electrode section 19 or the arc diffusion electrode section 25. If the direction of the current in each coil electrode part 17, 22 is the same, the direction of each axial magnetic field will be the same, and the magnetic flux density distribution of A+B will be as shown on the left side of FIG. 3, and the contact electrode part 19 Although a large axial magnetic field is applied in the arc diffusion electrode section 25, the axial magnetic field is small in the arc diffusion electrode section 25, so that arc concentration occurs.

FIG. 4 shows a second embodiment of the present invention, in which a contact electrode part/axial magnetic field generating part 21' is cup-shaped and has a plurality of inclined grooves 21' inclined in the same circumferential direction on the peripheral wall.
It is formed by providing a. In this case, since the current flows along the inclined groove 21'a, the current has a circumferential component (in the opposite direction to the current flowing through the coil portion 22c) and generates an axial magnetic field. This axial magnetic field is smaller than the axial magnetic field generated by the coil portion 22c and is opposite in direction. This example also has the same effects as the previous embodiment, but it also has the advantage that the structure of the contact electrode section/axial magnetic field generating section 21' is much simpler than that of the previous embodiment. In this example as well, the fixed electrode and the movable electrode have the same shape.

Incidentally, in each of the above embodiments, the coil electrode portion 22
is attached to the electrode rod 16, but it may be attached to the contact electrode portion and axial magnetic field generation portion 21, 21'. or,
If a material with a small cutting current value is used for the contact electrode part 19 and the contact electrode part/axial magnetic field generating part 21', it is possible to perform the charging and cutting with low surge.
Furthermore, with normal current, the shearing is completed before it transfers to the arc diffusion electrode section 25, but in the case of a fault current that is about an order of magnitude larger, the arc transfers to the arc diffusion electrode section 25, so the arc diffusion electrode section 25 is If it is made of Cu or Be, which has good shearing characteristics and withstand voltage characteristics, it is possible to improve the shearing characteristics and withstand voltage characteristics.

As described above, in the present invention, since no current flows through the large-diameter coil electrode portion during normal energization, temperature rise due to heat loss is reduced. In addition, since an axial magnetic field is generated in the contact electrode part and axial magnetic field generating part from the beginning of the shearing, the concentration of the arc is prevented even at the beginning of the shearing, and this axial magnetic field is relatively weak. The arc can move to the arc diffusion electrode part at an early stage, and since this axial magnetic field is opposite in direction to the axial magnetic field generated by the coil electrode part, the combined axial magnetic field in the process of arc migration is It is uniformly distributed in the contact electrode part/axial magnetic field generation part and the arc diffusion electrode part, and it is possible to prevent concentration of the arc even in the process of arc migration, and for these reasons, the shearing ability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of a conventional vacuum breaker, and FIGS. 2A to 2C are longitudinal sectional front views of electrodes of a vacuum breaker according to the first embodiment of the present invention, and small-diameter coil electrodes. FIG. 3 is a diagram of the magnetic flux density distribution of the axial magnetic field during the transition process of the arc, and FIG. 4 is a cross-section of the vacuum shield according to the second embodiment of the present invention. FIG. 3 is a longitudinal sectional front view of the electrode portion of the device. 1... Insulating tube, 2, 3... End plate, 7... Bellows, 17... Small diameter coil electrode section, 18... Connection conductor, 19... Contact electrode section, 21, 21'... Contact electrode section Also axial magnetic field generating part, 22... Large diameter coil electrode part, 23... Connection conductor, 24... Spacing,
25...Arc diffusion electrode section.

Claims (1)

[Claims] 1. In a vacuum shield disconnector in which a pair of electrodes are arranged facing each other through electrode rods in a vacuum container so as to be able to freely approach and separate, a contact is attached to the tip of the electrode rod, generates an axial magnetic field, and makes contact with the opposing electrode. an electrode section/axial magnetic field generation section; and a contact electrode section/axial magnetic field generation section that is attached to the electrode rod or contact electrode section/axial magnetic field generation section and generates a larger axial magnetic field in the opposite direction to the axial magnetic field; A coil electrode section with a larger diameter than the magnetic field generation section, and an arc diffusion electrode that is attached to the coil electrode section via a connecting conductor and is concentrically arranged at a distance around the outer periphery of the contact electrode section and axial magnetic field generation section. A vacuum disconnector characterized in that an electrode is composed of a part and a part.