JPS63170823A - Vacuum switch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a vacuum switch with an improved electrode structure.

(Prior art) In general, a vacuum switch is shown in a vertical cross-sectional view in Fig. 5.
A closing plate 2a,
A pair of electrodes 4.5 are placed inside the vacuum vessel 3 closed by 2b.
The electrodes 4.5 are fixed to the ends of a pair of conductive rods 6.7 which are inserted into the vacuum container 3 by penetrating the closing plates 2a and 2b from the outside. The conductive rod 7 is movable in the axial direction by an external operation mechanism (not shown), so that one electrode 5 can be brought into contact with and separated from the other electrode 4. Roughly speaking, a bellows 8 is provided between the one closure plate 2b and the conductive rod 7, which can keep the inside of the vacuum container 3 airtight and allow the conductive rod 7 to move in the axial direction. Furthermore, in order to quickly adhere and capture metal vapor generated between the pair of electrodes 4.5, the electrodes 4.5
A shield 9 is fixedly provided inside the cylindrical body 1 so as to surround the conductive rods 6 and 7.

In a vacuum switch having such a configuration, the electrodes 4.5 are in a contact state during normal energization, but when the conductive rod 7 is moved in the direction of the arrow shown in the figure by the operation of an external operating mechanism (not shown) from this state, one side The electrode 5 is separated from the other electrode 4, and an arc is generated between the two electrodes 4.5. This arc is maintained by the generation of metal vapor from the cathode, for example, the electrode 5, and when the current zero point is reached, the generation of metal vapor stops, and the arc can no longer be maintained and the interruption is completed.

By the way, if the breaking current is large, the arc generated between the electrodes 4 and 5 becomes extremely unstable due to the interaction between the magnetic field generated by the arc itself and the magnetic field created by the external circuit. For this reason, the arc moves along the electrode surface and is biased toward the edge or periphery of the electrode, overheating that area and releasing a lot of steam, lowering the degree of vacuum inside the vacuum vessel 3, resulting in vacuum opening/closing. This will reduce the breaking performance of the device.

Therefore, it has been known that applying a magnetic field perpendicular to the electrode surface (hereinafter referred to as 1ffl!1 field) is an effective means of preventing such a phenomenon. The outline will be described below. That is, it is generally said that the ratio of electrons, neutral atoms, and ionized atoms generated from the cathode spot of the arc is 100:10:1.

Therefore, when a vertical magnetic field is applied to the electrode surface, the electrons are captured by the magnetic field and move in a spiral pattern to reach the anode from the cathode.

Therefore, since the energy incident on the anode electrode is reduced, the electrode will not melt, and the vertical magnetic field against the electrode surface will capture the ion raw metal ra<plasma) that escapes to the outside of the electrode, and prevent it from escaping to the outside of the electrode. This will prevent this and stabilize the arc.

FIG. 6 is a longitudinal sectional view of this type of vertical magnetic field application type vacuum switch, in which the same parts as in FIG. 5 are denoted by the same reference numerals. In other words, as shown in FIG. 6, the coil conductor 4
3.53, and main electrodes 42.52. which sandwich the coil conductors 43.53, respectively. A pair of electrodes 41.51 consisting of an i5i and an auxiliary electrode 44.54 are provided facing each other in the vacuum container 3, and the electrodes 41.51 are fixed to the ends of a pair of conductive rods 6.7. are doing. FIG. 7 is an exploded perspective view showing the detailed configuration of one electrode 51 in FIG. 6. In FIG. 7, the coil conductor 53 is the coil conductor main electrode connection portion 31a.

32a to the main electrode 52, and the coil conductor sub-electrode connection parts 31b and 32b to the sub-type I! J54
electrically connected to. Therefore, the electrode 5 with such a configuration
1, the current flowing through the coil conductor 53 generates a longitudinal magnetic field on the electrode surface.

Note that the same applies to the other electrode 41.

However, with the vacuum switch having the configuration shown in Figures 6 and 7, although it is possible to generate a vertical magnetic field that is effective for interrupting fault current when it is energized, even when the normal rated current is energized, all the current is Since the current passes through the coil conductor 53, the rated current is limited by the heat loss of the coil conductor 53 itself.

(Problems to be Solved by the Invention) As described above, in conventional vacuum switches, when a short circuit is interrupted, it is possible to effectively generate a longitudinal magnetic field and improve the interrupting performance, but when the current is normally energized, heat loss due to the coil conductor There was a problem in that the rated current was limited.

The present invention has been made to solve the above-mentioned problems, and its purpose is to suppress heat loss to a small level and increase the rated current when normally energized, and to effectively generate a vertical magnetic field when breaking a short circuit. An object of the present invention is to provide a highly reliable vacuum valve that can significantly improve short-circuit breaking performance.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the present invention includes a vacuum container,
A vacuum constituted by a pair of conductive rods led out from the inside of the vacuum container, and a pair of electrodes that are fixedly attached to the tips of the pair of conductive rods and can be freely connected and separated within the vacuum container. In the switch, at least one of the pair of electrodes includes a first conductor joined to a conductive rod, a second conductor provided at a contact/separation part that contacts and separates from the other electrode of the electrodes, A ring-shaped conductor is arranged between the first conductor and the second conductor and is divided into a plurality of parts in the circumferential direction to electrically connect these conductors; It is characterized by comprising a non-linear resistor disposed in a non-contact state with the body and electrically connecting the first conductor and the second conductor.

(Function) In the vacuum switch described above, the first... Second
Because the nonlinear resistor that electrically connects the conductor is placed in a non-contact state with the annular conductor, when the normal rated current is applied.

The non-linear resistor has a low resistance, and most of the current is shunted to the non-linear resistor. Therefore, heat loss due to the annular conductor is small, and the rated current can be increased. Furthermore, when a fault current is applied, the nonlinear resistor becomes highly resistant due to Joule heat generated inside the nonlinear resistor, and most of the current is shunted to the annular conductor side. Therefore, it is possible to effectively generate a longitudinal magnetic field and improve short circuit breaking performance. In general, since the first conductors and the second conductors are directly connected by the annular conductor, mechanical strength during opening and closing of the electrodes can be improved.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical sectional view showing an example of the structure of a vacuum valve according to the present invention, and the same parts as in FIG. 6 are designated by the same reference numerals. In FIG. 1, a pair of electrodes 41 and 51 are provided in a vacuum vessel 3 in which openings at both ends of a cylindrical body 1 made of an insulator are closed by closing plates 2a and 2b, and a pair of electrodes 41 and 51 are provided facing each other. The electrodes 41 and 51 are fixed to the ends of a pair of conductive rods 6 and 7 that are inserted into the vacuum chamber 3 by penetrating through the conductive rods 2b from the outside, and one of the conductive rods 7 is rotated by an external operation mechanism (not shown). The electrode 51 is movable in the direction so that one electrode 51 can be moved toward and away from the other electrode 41. Further, the one closure plate 2b and the conductor 7
A conductive rod 7 is provided between the
A bellows 8 is provided that can allow movement in the axial direction. Furthermore, in order to quickly condense and capture metal vapor generated between the pair of electrodes 41 and 51, the electrodes 41 and 51 are
A shield 9 is fixedly provided inside the cylindrical body 1 so as to surround the conductive rods 6 and 7.

Here, the pair of electrodes 41.51 includes a disk-shaped sub-electrode 44.54 which is a first conductor joined to the conductive rod 6.5, and the other electrode 51.54 of the electrodes 41.51. A disk-shaped main electrode 42.52, which is a second conductor provided at a contact/separation part that contacts and separates from 41, a sub-electrode 44.54, and a main electrode 42.5.
a coil conductor 43 which is an annular conductor divided into two in the circumferential direction and is disposed between the electrodes 2 and 2 and electrically connects each of these electrodes;
53, and a cylindrical shape that is disposed at a substantially central position inside the coil conductor 43.53 in a non-contact state with the coil conductor and directly connects the sub-electrode 44.54 and the main electrode 42.52. 45° and 55° nonlinear resistors, respectively. In this case, the nonlinear resistor 45.55 has iron (Fe) as its main component, cobalt (Co),
It is made of a material to which nickel (Ni) or the like is added and has a high temperature coefficient of resistance.

FIG. 2 shows an example of a detailed configuration of one electrode 51 in an exploded perspective view, and the same parts as in FIG. 1 are denoted by the same reference numerals. Note that since the detailed configuration of the other electrode 41 is exactly the same, corresponding parts will be given the same subscripts and illustrations and explanations thereof will be omitted here.

In the vacuum switch described above, the sub-electrode 54 and the main electrode 52 constituting one electrode 51 are electrically connected separately by the coil conductor 53 and the non-linear resistor 55, so the main electrode The current flowing from the electrode 52 to the sub-electrode 54 is
The current is divided into a current flowing through the coil conductor 53 and a current flowing through the nonlinear resistor 55. In this case, the fraction of current flow is inversely proportional to each resistance value.

Therefore, in the normal rated current conduction state, the resistance value of the nonlinear resistor 55 is low, and most of the current is transferred to the main electrode 52.
The current is efficiently shunted from the source to the sub-electrode 54 through the non-linear resistor 55. Therefore, the resistance value of the electrode 51 as a whole is suppressed, heat loss is reduced, and the rated current can be increased. In addition, if a fault current occurs due to a short circuit accident, etc., and a large current passes through that causes a disconnection,
Since the nonlinear resistor 55 has a higher temperature coefficient of resistance than the coil conductor 53, the resistance value increases rapidly due to Joule heat generated inside the nonlinear resistor 55 (the nonlinear resistor 55 (Depending on the size and fault current value, the resistance value when fault current is applied reaches about 7 to 8 times the initial value). Therefore, since the current value to be shunted is determined by the ratio of each resistance value (the resistance value of the coil conductor 53 also increases at a constant rate, it is about 2 to 3 times the initial value, and the nonlinear resistor 5
5), most of the fault current is shunted from the main electrode 52 through the coil conductor 53 to the sub-electrode 54. Thereby, it is possible to improve the short-circuit breaking performance by generating an effective longitudinal magnetic field.Furthermore, the main electrode 52 and the sub-electrode 54 can be
5, the mechanical strength when opening and closing the electrodes can be improved.

FIGS. 3(a) and 3(b) show the above contents in circuit diagram form. That is, in the normal rated current conduction state, as shown in FIG. 3(a), the current is divided into the coil conductor resistance 53a and the nonlinear resistance 55a, and the heat loss is small. On the other hand, in a state where a fault current passes, as shown in FIG. 3(b), the nonlinear resistance 55b increases significantly due to internal Joule heat, but the coil conductor resistance 53b does not increase so much.

Therefore, since the current value to be shunted is determined by the ratio of the respective resistance values, most of the fault current passes through the coil conductor resistance 53b, resulting in the generation of a longitudinal magnetic field effective for disconnection.

To introduce a specific numerical example, in an electrode structure where the coil diameter of the coil conductor is 20 rim class, the coil conductor resistance at room temperature is 17 μΩ, the nonlinear resistance is 12 μΩ, and 41% of the passing current flows through the coil conductor. In contrast, the fault current 4
After 0KA passes for 0.06 seconds (3 cycles), the coil conductor resistance becomes 51 μΩ, the nonlinear resistance becomes 87 μΩ, and 63% of the passing current flows through the coil conductor.
This results in a longitudinal magnetic field of 1400 Gauss.

Here, the effective vertical magnetic field for cutting off is said to be about 30 gauss per KA (40KA x 30 gauss - 1200 gauss).
Gauss), it can be seen that an appropriate longitudinal magnetic field is generated.

Note that the same thing can be said about the other electrode 41 side as well.

It should be noted that the present invention is not limited to the embodiments described above, but can also be implemented in the following manner.

For example, in the above embodiment, the coil conductor is divided into two parts in the circumferential direction, but the present invention is not limited to this.
The same effect as described above can be obtained regardless of whether the coil conductor has one turn or multiple turns.

Further, in the above embodiment, the coil conductor, the III electrode, and the conductive rod are constructed separately, but the present invention is not limited to this. For example, as shown in FIG. 4, these can be integrally machined from a raw material. By doing so, it becomes possible to improve the manufacturing efficiency of the vacuum switch.

Furthermore, in the above embodiment, a case was described in which a non-linear resistor was provided on both of the pair of electrodes 41.51, but the present invention is not limited to this. A linear resistor may also be provided.

In addition, the present invention can be modified and implemented in various ways without changing the gist thereof.

〔Effect of the invention〕

As explained above, according to the present invention, at least one of the pair of electrodes is connected to the first conductor joined to the conductive rod, and the contact portion is provided at the contact portion that connects and separates from the other electrode of the electrodes. a second conductor; a ring-shaped conductor disposed between the first conductor and the second conductor and electrically connecting the conductors; Since it is composed of a non-linear resistor that is disposed inside the conductor in a non-contact state with the conductor and electrically connects the first conductor and the second conductor, heat is not generated during normal energization. In addition to minimizing loss and increasing the rated current, it is also possible to effectively generate a longitudinal magnetic field during short-circuit breaking, significantly improving short-circuit breaking performance, and improving mechanical strength when opening and closing electrodes. We can provide highly reliable vacuum pulp.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the vacuum switch according to the present invention, Fig. 2 is an exploded perspective view showing details of the electrode in the same embodiment, and Figs. 3(a) and (b) are the same embodiment. 4 is an exploded perspective view showing another embodiment of the present invention, and FIGS. 5 and 6 are longitudinal sectional views showing examples of the configuration of a conventional vacuum switch, respectively. FIG. 7 is an exploded perspective view showing details of the electrode in FIG. 6. DESCRIPTION OF SYMBOLS 1... Cylindrical body, 2a, 2b... Closure plate, 3... Vacuum container, 4, 5... Electrode, 6, 7... Conductive rod, 8...
... Bellows, 9... Shield, 41.51... Electrode, 42.52... Main electrode, 43.53... Coil conductor, 44.54... Sub-electrode, 45.55...・Nonlinear resistor. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 (a) Figure 3 (b) Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) A vacuum container, a pair of conductive rods led out from the inside of the vacuum container, and a pair of electrodes that are fixedly attached to the tips of the pair of conductive rods and can be freely connected and separated within the vacuum container. In the vacuum switch, at least one of the pair of electrodes is connected to the first conductive rod.
a second conductor provided at a contact/disconnection part that contacts and separates from the other electrode of the electrodes, and a second conductor disposed between the first conductor and the second conductor. an annular conductor divided into a plurality of parts in the circumferential direction that electrically connects each of these conductors; 1. A vacuum switch comprising: a non-linear resistor that electrically connects a second conductor. (2) The nonlinear resistor has iron as its main component, cobalt,
The vacuum switch according to claim (1), which is made of a material to which nickel or the like is added.