EP3370243A1

EP3370243A1 - Vacuum circuit breaker

Info

Publication number: EP3370243A1
Application number: EP18156010.3A
Authority: EP
Inventors: Kazuhiro Satou; Takashi Sato; Masato Yabu; Kozo Tamura; Yuuki Tai
Original assignee: Hitachi Industrial Equipment Systems Co Ltd
Current assignee: Hitachi Industrial Equipment Systems Co Ltd
Priority date: 2017-03-03
Filing date: 2018-02-09
Publication date: 2018-09-05
Anticipated expiration: 2038-02-09
Also published as: CN108538680A; JP6776156B2; CN108538680B; JP2018147643A; EP3370243B1

Abstract

It is possible to reduce a stress due to an impact and a vibration caused by an operation of opening or closing the vacuum circuit breaker without increasing a weight and a size of a vacuum circuit breaker, to thereby reduce a bend of a case of an operating mechanism part and to thereby improve a reliability to the operation of opening or closing the vacuum circuit breaker. A vacuum circuit breaker of the present invention is a vacuum circuit breaker that includes a vacuum valve, in which at least a fixed side electrode and a movable side electrode are stored and whose periphery is covered with a mold part, and an operating mechanism part which drives the movable side electrode, and is characterized in that the vacuum valve and the operating mechanism part are arranged on a straight line and characterized by including a fixing member which extends over and fixes the mold part of the vacuum valve and the operating mechanism part.

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to a vacuum circuit breaker and, in particular, to a vacuum circuit breaker suitably applied to a mold vacuum valve in which a vacuum valve is molded with a solid insulating material.

BACKGROUND ART

One of a conventional technique related to a vacuum circuit breaker is a technique described in Japanese Patent Laid-Open No. 2003-333715 (Patent Document 1). In this Patent Document 1, a switch gear which is provided with a plurality of components including a switch gear component, an insulating part to insulate the switch gear component, and a bonding part to bond the switch gear component in a vertical direction and which bonds the plurality of components in a vertical direction is described as a switch gear of an encapsulated type which stores an opening/ closing part including a valve of a vacuum circuit breaker or a vacuum disconnector in a switch gear and which constructs a power supply system.
The switch gear described in the Patent Document 1 is mounted with a vacuum circuit breaker to which a mold vacuum valve having a vacuum valve covered with an insulating material is applied, and the mold vacuum valve is constructed in such a way as to be in contact with only a ceiling plate of an operating chamber. Namely, the mold vacuum valve is fixed at a portion in contact with the ceiling plate of an operating mechanism part. Specifically, a fixing part such as a nut or a bolt is embedded in a mold part in contact with the ceiling plate of the operating mechanism part, and the vacuum circuit breaker is fixed_to the ceiling plate of the operating mechanism part by the fixing part.
However, according to a construction described in the Patent Document 1, it is concerned that the bolt or the nut is loosened by a driving of the operating mechanism part, in other words, by an impact and a vibration caused by an operation of opening or closing the vacuum circuit breaker, whereby the operation of opening or closing the vacuum circuit breaker is made unstable. Further, it is also concerned that a case of the operating mechanism part is bent by the impact and the vibration caused by the operation of opening or closing the vacuum circuit breaker, whereby a speed of opening or closing the vacuum circuit breaker is reduced.
As a countermeasure against this, it is thought that a size of the fixing part such as the bolt or the nut is increased to thereby increase a fastening force of the fixing part or that a plate thickness of the case of the operating mechanism part is increased to thereby inhibit the case of the operating mechanism from being bent. However, this countermeasure inevitably presents a problem such that the vacuum circuit breaker is increased in weight and size.
The present invention has been made in view of the above-mentioned problem, and an object of the present invention is to provide a vacuum circuit breaker that can reduce a stress due to an impact and a vibration caused by an operation of opening or closing the vacuum circuit breaker without increasing a weight and a size of the vacuum circuit breaker to thereby reduce a bend of a case of the operating mechanism part and to thereby improve a reliability to the operation of the opening or closing the vacuum circuit breaker.

SUMMARY OF THE INVENTION

In order to achieve the object described above, a vacuum circuit breaker of the present invention is a vacuum circuit breaker that includes a vacuum valve, in which at least a fixed side electrode and a movable side electrode are stored and whose periphery is covered with a mold part, and an operating mechanism part which drives the movable side electrode, and is characterized in that the vacuum valve and the operating mechanism part are arranged on a straight line and characterized by including a fixing member which extends over and fixes the mold part of the vacuum valve and the operating mechanism part.
According to the present invention, without increasing a weight and a size of the vacuum circuit breaker, it is possible to reduce a stress due to an impact and a vibration caused by an operation of opening or closing the vacuum circuit breaker and to reduce a bend of a case of the operating mechanism part and to improve a reliability to the operation of the opening/ closing the vacuum circuit breaker.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial cross-sectional view of a vacuum circuit breaker of a first embodiment according to one embodiment of the present invention.
FIG. 2 is a partial cross-sectional view of a vacuum circuit breaker of a second embodiment according to another embodiment of the present invention.
FIG. 3 is a partial cross-sectional view of a vacuum circuit breaker of a third embodiment according to still another embodiment of the present invention.
FIG. 4 is a partial cross-sectional view of a vacuum circuit breaker of a fourth embodiment according to still another embodiment of the present invention.
FIG. 5 is a graph to show a Paschen's curve to illustrate a relationship between a pressure in a vacuum vessel and a discharge start voltage in the vacuum circuit breaker shown in FIG. 4.
FIG. 6 shows a vacuum circuit breaker of a fifth embodiment according to still another embodiment of the present invention and is a view corresponding to a cross section along a line A - A' of FIG. 2.
FIG. 7 is a partial cross-sectional view of a vacuum circuit breaker of a sixth embodiment according to still another embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a vacuum circuit breaker of the present invention will be described on the basis of illustrated embodiments. Same reference signs will be used for same constituent parts in the respective embodiments.

[First Embodiment]

FIG. 1 is a partial cross-sectional view of a vacuum circuit breaker of a first embodiment according to an embodiment of the present invention.
As shown in FIG. 1, a vacuum circuit breaker 30A of the present embodiment is roughly constructed of: a vacuum valve 1 which is integrally molded with a solid insulating material such as an epoxy resin (whose periphery is covered with a mold part 1A); a fixed side cable bushing 2 in which a periphery of a fixed side cable bushing conductor 15 is molded; a movable side cable bushing 3 in which a periphery of an outside portion of a movable side cable bushing conductor 16 is molded; and an operating mechanism part 4 which operates a movable side electrode 13 which will be described later. Usually, the vacuum valve 1 molded with the solid insulating material such as the epoxy resin is referred to as a mold vacuum valve. Although not especially shown, a mold part is usually grounded.
The vacuum valve 1 described above is constructed of: a fixed side end plate 6 bonded to one end of a cylindrical insulating member 5; a fixed side conductor 7 which airtightly passes through the fixed side end plate 6; a movable side end plate 8 which is bonded to the other end of the cylindrical insulating member 5; a bellows 9 which is shaped like a serpentine belly and whose one end is bonded to the movable side end plate 8 and which allows a movable part to move; and a movable side conductor 10 which airtightly passes through the bellows 9 and which moves in an axial direction while keeping a vacuum. An internal pressure in the vacuum valve 1 is held in a vacuum equal to or less than approximately 10^-2 Pa.
In the vacuum valve 1, a floating potential metal 11 supported by the cylindrical insulating material 5, a fixed side electrode 12 connected to an end portion of the fixed side conductor 7, and the movable side electrode 13 connected to an end portion of the movable side conductor 10 are arranged.
The movable side conductor 10 is connected to an operating insulating rod 14, and the operating insulating rod 14 is connected to an operating part which is stored in the operating mechanism part 4 and which is coupled to a wipe mechanism to apply a contact load to a pair of electrodes. A space surrounding the operating insulating rod 14 is filled with an insulating gas 18 such as air and sulfur hexafluoride.
Further, when the movable side electrode 13 moves via the operating insulating rod 14 in conjunction with a movement of the operating part (not shown), the fixed side electrode 12 and the movable side electrode 13 can be brought into contact with or separated from each other, that is, an opened state and a closed state of the vacuum valve 1 can be switched. The vacuum valve 1 shown in FIG. 1 shows the opened state.
The fixed side cable bushing 2 electrically connects the fixed side cable bushing conductor 15 to the fixed side conductor 7 of the vacuum valve 1, and the movable side cable bushing 3 has the movable side cable bushing conductor 16 arranged on a movable side of the vacuum valve 1 and is integrally molded with the solid insulating material such as the epoxy resin, and the movable side conductor 10 and the movable side cable bushing conductor 16 of the vacuum valve 1 are electrically connected to each other via a contactor 17 capable of sliding and passing electricity, and the fixed side cable bushing 2 and the movable side cable bushing 3 have a power supply side cable and a load side cable, both of which are not shown, connected thereto respectively. In this way, the vacuum valve 1 is constructed in such a way as to be operated.
Then, the vacuum circuit breaker 30A of the present embodiment is constructed as follows: the vacuum valve 1 and the operating mechanism part 4 are arranged nearly on a straight line; and a fixing member 19 is provided which extends over and integrally fixes the mold part 1A on a periphery of the vacuum valve 1 and the operating mechanism part 4.
Specifically, a portion on a vacuum valve 1 side of the fixing member 19 is fixed to a plurality of mold protruding portions (integrally molded with the mold part 1A) 20a, 20b, each of which is formed on an outside portion of a side surface of the mold part 1A of the vacuum valve 1 in such a way as to protrude and has an insert nut embedded therein, with bolts 21a, 21b of fixing means, whereas a portion on an operating mechanism part 4 side of the fixing member 19 is directly fixed to a case of the operating mechanism part 4 with bolts 21c, 21d, of fixing means (the operating mechanism part 4 does not have but may have a protruding part).
The vacuum circuit breaker 30A of the present embodiment constructed in this way can receive a driving force of the operating mechanism part 4, that is, a stress due to an impact and a vibration caused by an operation of opening or closing the vacuum circuit breaker 30A also by the fixing member 19 and hence the stress can be dispersed. Namely, the mold part 1A of the vacuum valve 1 and the case of the operating mechanism part 4 are fixed at a plurality of portions with the bolts 21a, 21b, 21c, 21d via the fixing member 19, so the stress due to the impact and the vibration caused by the operation of opening or closing the vacuum circuit breaker 30A can be dispersed at respective fixed portions.
As a result, a trouble such that the bolts 21a, 21b, 21c, 21d and nuts to fix the molded vacuum valve 1 and the operating mechanism part 4 are loosened can be reduced, and the operating mechanism part 4 can be inhibited from being bent, whereby the molded vacuum valve 1 or the vacuum circuit breaker 30A mounted with the molded vacuum valve 1 can be reduced in size, and a reliability to the operation of opening or closing the vacuum circuit breaker 30A can be further improved.

[Second Embodiment]

FIG. 2 is a partial cross-sectional view of a vacuum circuit breaker of a second embodiment according to another embodiment of the present invention. Descriptions of the same parts as the first embodiment will be omitted.
A vacuum circuit breaker 30B of the present embodiment shown in FIG. 2 is constructed in such a way that the fixing member 19 extends over the mold part 1A on a periphery of the vacuum valve 1 and the operating mechanism part 4 at a plurality of positions.
Namely, the fixing member 19 is plurally arranged and the respective fixing members 19a, 19b extend over the mold part 1A of the vacuum valve 1 and the operating mechanism part 4 and are fixed to a plurality of mold protruding portions 20a, 20b, each of which is formed on a side surface of the mold part 1A of the vacuum valve 1 in such a way as to protrude, and to the case of the operating mechanism part 4 with bolts 21a, 21b, 21c, 21d of fixing means. The other construction is the same as the first embodiment.
The vacuum circuit breaker 30B of the present embodiment constructed in this manner receives the driving force of the operating mechanism part 4, that is, a stress due to an impact and a vibration caused by an operation of opening or closing the vacuum circuit breaker 30B by two fixing members 19a, 19b, so the stress received by one fixing member 19 can be reduced more than the first embodiment. Hence, a trouble such that the bolts 21a, 21b, 21c, 21d and the nuts to fix the molded vacuum valve 1 and the case of the operating mechanism part 4 are loosened or a trouble such that the operating mechanism part 4 is bent can be inhibited more than the first embodiment. Therefore, a reliability to the operation of opening or closing the molded vacuum valve 1 or the vacuum circuit breaker 30B mounted with the molded vacuum valve 1 can be further improved.

[Third Embodiment]

FIG. 3 is a partial cross-sectional view of a vacuum circuit breaker of a third embodiment according to still another embodiment of the present invention. Descriptions of the same parts as the first embodiment will be omitted.
In a vacuum circuit breaker 30C of the present embodiment shown in FIG. 3, the fixing member 19 is arranged also on a side surface of the fixed side cable bushing 2 located on a side opposite to the operating mechanism part 4.
Namely, the fixing member 19 is extended in an axial direction and is bent inside by approximately 90 degrees at a position over the fixed side cable bushing 2, and this bent fixing member 19' is fixed to a mold protruding portion 20c, which is formed in a mold part to cover a periphery of the fixed cable bushing 2 and in which an insert nut is embedded, by a bolt 21e of a fastening means. The other construction is the same as the first embodiment.
The fixing member 19 is extended in the axial direction and intersects the fixed side cable bushing 2, which can be realized by forming a through hole through which the fixing member 19 can be passed in the fixed side cable bushing 2. Further, the fixing member 19 can also be arranged in such a way that the fixing member 19 does not intersect the fixed side cable bushing 2 and avoids the fixed side cable bushing 2.
The vacuum circuit breaker 30C of the present embodiment constructed in this manner has the bent fixing member 19' and hence can disperse the driving force of the operating mechanism part 4, that is, the stress due to an impact and a vibration caused by the operation of opening or closing the vacuum circuit breaker 30C more than the first embodiment. Hence, a trouble such that the bolts 21a, 21b, 21c, 21d and the nuts to fix the molded vacuum valve 1 and the case of the operating mechanism part 4 are loosened or a trouble such that the operating mechanism part 4 is bent can be inhibited more than the first embodiment. Therefore, a reliability to the operation of opening or closing the molded vacuum valve 1 or the vacuum circuit breaker 30C mounted with the molded vacuum valve 1 can be further improved.
Although a case where one fixing member 19 is arranged has been shown in the present embodiment, in a case where a plurality of fixing members 19 are arranged, it is clear that an effect of improving the reliability becomes more remarkable.

[Fourth Embodiment]

FIG. 4 is a partial cross-sectional view of a vacuum circuit breaker of a fourth embodiment according to still another embodiment of the present invention. Descriptions of the same parts as the first embodiment will be omitted.
In a vacuum circuit breaker 30D of the present embodiment shown in FIG. 4, as is the case with the first embodiment, a portion on a vacuum valve 1 side of the fixing member 19 is fixed to the mold protruding portion by a bolt and a portion on an operating mechanism part 4 side of the fixing member 19 is directly fixed to the case of the operating mechanism part 4 by bolts 21c, 21d of fastening means. However, in the present embodiment, the fixing bolt 21a to fix the fixing member 19 by the mold protruding portion located on a periphery of the floating potential metal 11 is an inspection bolt 22 to inspect a pressure (degree of vacuum) in the vacuum valve 1. This inspection bolt 22 and an inspection insert nut 23, which pairs with the inspection bolt 22, fix the fixing member 19 at a position separated from the floating potential metal 11 by a predetermined distance. The inspection bolt 22 and the inspection insert nut 23 are electrically insulated from the fixing member 19 via an insulating member 24.
Further, the inspection bolt 22 has a pressure monitoring device 25, which detects a potential increase in the floating potential metal 11 when the pressure in the vacuum valve 1 increases, connected thereto, and has a determination device 26 which determines whether or not the internal pressure in the vacuum valve 1 is abnormal from an inspection signal detected by the pressure monitoring device 25.
The pressure monitoring device 25 is constructed of: a connection line 25a which is connected to at least one of the inspection bolt 22 and the inspection insert nut 23; a plurality of insulating components (for example, capacitors) 25b1, 25b2 which are connected partially in series to at least one of the inspection bolt 22 and the inspection insert nut 23 via the connection line 25a; and a potential measuring device 25c which is connected between the plurality of insulating components 25b1, 25b2. Then, of the plurality of insulating components 25b1, 25b2 which are connected partially in series to at least one of the inspection bolt 22 and the inspection insert nut 23, the insulating component 25b2 which is different from the insulating component 25b1 located close to the inspection bolt 22 and the inspection insert nut 23 is connected to a potential fixed point (earth) 25b.
The vacuum circuit breaker 30D of the present embodiment constructed in this manner has the pressure monitoring device 25 connected to the inspection volt 22, so in a case where a pressure deterioration is caused in the vacuum valve 1 and hence a potential is generated on the inspection bolt 22, the vacuum circuit breaker 30D can monitor whether or not the internal pressure in the vacuum valve 1 is abnormal.
Here, a case where the pressure deterioration in the vacuum valve 1 is caused, that is, a case where a pressure in a vacuum vessel increases will be described.
In general, a pressure increase in a vacuum vessel is mainly caused by a gas permeation from the outside of the vacuum vessel, a gas emission from an internal member of the vacuum vessel, and a pinhole rarely caused in the bellows 9 and a bonded portion, and as shown by a Paschen' s curve which expresses a relationship between a pressure in a vacuum vessel and a discharge start voltage and is shown in FIG. 5, when the pressure in the vacuum vessel becomes 10^-1 Pa or more, an insulation performance starts to quickly decrease.
When the vacuum circuit breaker 30D mounted with the vacuum valve 1 is in a normal operating state, if a pressure increase is caused in the vacuum valve 1 and the insulation performance is decreased, a discharge occurs between a main circuit, which is composed of the fixed side conductor 7, the fixed side electrode 12, the movable side conductor 10, and the movable side electrode 13, and the floating potential metal 11 which is electrically insulated from the main circuit.
A potential of the floating potential metal 11 at the time of a normal operation when the pressure increase is not caused in the vacuum valve 1 is roughly determined by an operating voltage, a structure of the vacuum valve 1, and an arrangement of a fixed potential member on a periphery of the vacuum valve 1 (for example, a case or a floor of a vehicle), whereas a potential of the floating potential metal 11 when the pressure increase is caused and a discharge occurs between the main circuit of the vacuum valve 1 and the floating potential metal 11 becomes a potential in which a discharge pulse is superimposed on the potential at the time of the normal operation. Further, when the pressure is more increased, an increased discharge pulse is superimposed on the potential and, finally, the potential of the floating potential metal 11 is increased to a state close to the operating voltage.
A potential increase in the floating potential metal 11 when the pressure is increased in the vacuum valve 1 is detected by the pressure monitoring device 25 connected to the inspection bolt 22 and its detection signal is outputted to the external determination device 26, whereby the soundness of the internal pressure in the vacuum valve 1 (whether or not the internal pressure in the vacuum valve 1 is abnormal) can be gotten.
According to this vacuum circuit breaker 30D of the present embodiment, not only the same effect as the first embodiment can be produced but also the internal pressure in the vacuum valve 1 can be monitored. Hence, an insulation reliability of the vacuum valve 1 can be improved, in other words, the reliability of the vacuum circuit breaker 30D can be improved.

[Fifth Embodiment]

FIG. 6 shows a vacuum circuit breaker of a fifth embodiment according to still another embodiment of the present invention and is a drawing corresponding to a cross section along a line A - A' in FIG. 2. Descriptions of the same parts as the fourth embodiment will be omitted.
A vacuum circuit breaker 30E of the present embodiment shown in FIG. 6 is constructed in such a way that the fixing members 19 are arranged at two portions and that these fixing members 19 extend over the mold part 1A on the periphery of the vacuum valve 1 and over the operating mechanism part 4. The fixing members 19, as is the case with the fourth embodiment, are fixed to the mold part 1A on the periphery of the vacuum valve 1 and to the case of the operating mechanism part 4, but the inspection insert nuts 23a, 23b which pair with the inspection bolts 22a, 22b, which are arranged plurally (in the present embodiment, by two) in a peripheral direction, are fixed at positions separated from the floating potential metal 11 by a predetermined distance. The inspection bolts 22a, 22b and the inspection insert nuts 23a, 23b are electrically insulated from the fixing members 19 by the insulating member 24.
Further, in the present embodiment, the inspection insert nuts 23a, 23b which are different from each other in a total length are embedded respectively in the mold protruding portion 20a.
The vacuum circuit breaker 30E of the present embodiment constructed in this manner can produce the same effect as the first embodiment, which is needless to say, and distances between the floating potential metal 11 of the vacuum valve 1 and the inspection insert nuts 23a, 23b are different from each other, in other words, distances L1 and L2 shown in FIG. 6 are different from each other, so potentials generated at the inspection bolts 22a, 22b can be made different from each other.
In FIG. 6, the vacuum circuit breaker 30E is constructed in such a way that a distance between the inspection insert nut 23a on an upper side and the floating potential metal 11 of the vacuum valve 1 is shorter than a distance between the inspection insert nut 23b on a lower side and the floating potential metal 11 of the vacuum valve 1. When the internal pressure in the vacuum valve 1 increases, first, a potential of the inspection insert nut 23a on the upper side increases. Further, when the internal pressure in the vacuum valve 1 increases, a potential of the inspection insert nut 23b on the lower side increases. If a relationship between an increase in the internal pressure in the vacuum valve 1 and an increase in the potential of the inspection insert nuts 23a, 23b is gotten in advance, the potentials of the insert nuts 23a, 23b become a simple pressure gage and hence a degree of deterioration of the internal pressure in the vacuum valve 1 can be gotten.
Two inspection bolts 22a, 22b are shown in the present embodiment, but when a plurality of inspection bolts are arranged in a peripheral direction, an accuracy of measuring the internal pressure in the vacuum valve 1 can be improved according to the number of the inspection bolts.

[Sixth Embodiment]

FIG. 7 is a partial cross-sectional view of a vacuum circuit breaker of a sixth embodiment according to still another embodiment of the present invention. Descriptions of the same parts as the first embodiment and the fourth embodiment will be omitted.
In a vacuum circuit breaker 30F of the present embodiment shown in FIG. 7, a set of one inspection bolt 22a1 (or 22a2, 22a3) and one inspection insert nut 23a1 (or 23a2, 23a3) which pairs with the one inspection bolt 22a1 (or 22a2, 22a3) are arranged plurally (in the present embodiment, by three) on the mold part 1A of the periphery of the vacuum valve 1 and in an axial direction of the floating potential metal 11, and the three inspection insert nuts 23a1, 23a2, 23a3 arranged in the axial direction of the floating potential metal 11 are arranged in such a way that distances between the three inspection insert nuts 23a1, 23a2, 23a3 and the floating potential metal 11 are different from each other.
Specifically, the fixing member 19 is constructed in a such a way as to extend over the mold part 1A on the periphery of the vacuum valve 1 and over the operating mechanism part 4 and the fixing member 19 is fixed to the mold part 1A on the periphery of the vacuum valve 1 and to the case of the operating mechanism part 4. At this time, the fixing member 19 arranged on the periphery of the floating potential metal 11 is fixed to the mold part 1A on the periphery of the vacuum valve 1 at three portions by the inspection bolts 22a1, 22a2, 22a3 and the inspection insert nuts 23a1, 23a2, 23a3, which pair with the inspection bolts 22a1, 22a2, 22a3, in such a way that the inspection insert nuts 23a1, 23a2, 23a3 are different from each other in a distance from the floating potential metal 11.
The respective inspection bolts 22a1, 22a2, 22a3 and the respective inspection insert nuts 23a1, 23a2, 23a3 are electrically insulated from the fixing member 19 by the insulating member 24.
Further, in the present embodiment, the inspection insert nuts 23a1, 23a2, 23a3, which are different from each other in a total length, are respectively embedded in protruding parts 20a1, 20a2, 20a3 of the mold part 1A on the periphery of the vacuum valve 1.
The vacuum circuit breaker 30F of the present embodiment constructed in this manner can produce the same effect as the first embodiment, which is needless to say, and since the distances between the floating potential metal 11 of the vacuum valve 1 and the respective inspection insert nuts 23a1, 23a2, 23a3 are different from each other, the potentials generated at the inspection bolts 22a1, 22a2, 22a3 can be made different from each other.
For example, in FIG. 7, a distance between the inspection insert nut 23a1 on the left side and the floating potential metal 11 of the vacuum valve 1 is the shortest, and a distance between the inspection insert nut 23a2 and the floating potential metal 11 of the vacuum valve 1 is shorter, and then a distance between the inspection insert nut 23a3 on the right side and the floating potential metal 11 of the vacuum valve 1 is long. When the internal pressure in the vacuum valve 1 increases, first, the potential of the inspection insert nut 23a1 on the left side increases, and when the internal pressure in the vacuum valve 1 increases more, the potential of the inspection insert nut 23a2 increases, and when the internal pressure in the vacuum valve 1 increases still more, the potential of the inspection insert nut 23a3 increases. If a relationship between an increase in the internal pressure in the vacuum valve 1 and an increase in the potential of the inspection insert nuts 23a1, 23a2, 23a3 is gotten in advance, the potentials of the insert nuts 23a1, 23a2, 23a3 become a simple pressure gage and hence a degree of deterioration of the internal pressure in the vacuum valve 1 can be gotten.
Three inspection bolts 22a1, 22a2, 22a3 are shown in the present embodiment, but when the inspection bolts are arranged additionally in the axial direction, an accuracy of measuring the internal pressure in the vacuum valve 1 can be improved according to the number of the inspection bolts.
The above-mentioned embodiments have been described in detail so as to explain the present invention in a way that is easy to understand, and the present invention is not necessarily limited to a vacuum circuit breaker having the whole construction described above. Further, a portion of the construction of one embodiment can be replaced by the construction of the other embodiment, and the construction of one embodiment can be added to the construction of the other embodiment. Still further, in a portion of the construction of each embodiment, the construction of one embodiment can be added to or deleted from or replaced with the construction of the other embodiment.

REFERENCE SIGNS LIST

1---vacuum valve
1A---mold part of vacuum valve
2---fixed side cable bushing
3---movable side cable bushing
4---operating mechanism part
5---cylindrical insulating member
6---fixed side end plate
7---fixed side conductor
8---movable side end plate
9---bellows
10---movable side conductor
11---floating potential metal
12---fixed side electrode
13---movable side electrode
14---operating insulating rod
15---fixed side cable bushing conductor
16---movable side cable bushing conductor
17---contactor
18---insulating gas
19, 19a, 19b---fixing member
19'---bent fixing member
20a, 20b, 20c, 20a1, 20a2, 20a3---mold protruding portion
21a, 21b, 21c, 21d, 21e---bolt
22, 22a, 22b, 22a1, 22a2, 22a3---inspection bolt
23, 23a, 23b, 23a1, 23a2, 23a3---inspection insert nut
24---insulating member
25---pressure monitoring device
25a---connection line
25b1, 25b2---insulating component
25c---potential measuring device
25d---potential fixed point
26---determination device
30A, 30B, 30C, 30D, 30E, 30F---vacuum circuit breaker

Claims

A vacuum circuit breaker (30A) comprising a vacuum valve (1), in which at least a fixed side electrode (12) and a movable side electrode (13) are stored and whose periphery is covered with a mold part (1A), and an operating mechanism part (4) which drives the movable side electrode (13), characterized in that
the vacuum valve (1) and the operating mechanism part (4) are arranged on a straight line, and
a fixing member (19) which extends over and fixes the mold part (1A) of the vacuum valve (1) and the operating mechanism part (4) is provided.
The vacuum circuit breaker according to claim 1,
characterized in that the fixing member (19) is fixed to a plurality of mold protruding portions (20a, 20b), which are provided on a side surface of the mold part (1A) of the vacuum valve (1) in such a way as to protrude, and to the operating mechanism part (4) with fastening means (21a, 21b).
The vacuum circuit breaker according to claim 2, characterized in that the vacuum valve (1) is constructed of:
a fixed side end plate (6) which is bonded to one end of a cylindrical insulating member (5); a fixed side conductor (7) which airtightly passes through the fixed side end plate (6) ;

a movable side end plate (8) which is bonded to the other end of the cylindrical insulating member (5); a bellows (9) whose one end is bonded to the movable side end plate (8) and which allows a movable part to move; and a movable side conductor (10) which airtightly passes through the bellows (9) and moves in an axial direction while keeping a vacuum, and
wherein in the vacuum valve (1), a floating potential metal (11) supported by the cylindrical insulating member (5), the fixed side electrode (12) connected to an end portion of the fixed side conductor (7), and the movable side electrode (13) connected to an end portion of the movable side conductor (10) are arranged.
The vacuum circuit breaker according to claim 3, comprising:
a fixed side cable bushing (2) which is electrically connected to the fixed side conductor (7); and

a movable side cable bushing (3) which is electrically connected to the movable side conductor (10),

characterized in that the fixing member (19) is arranged also on a side surface of the fixed side cable bushing (2) located on a side opposite to the operating mechanism part (4).
The vacuum circuit breaker according to claim 4,
characterized in that the fixing member (19) extends in the axial direction and bends inside at a position over the fixed side cable bushing (2), and the bent fixing member (19') is fixed to the mold protruding portion (20c) provided at the mold part of the fixed side cable bushing (2) with a fastening means (21e).
The vacuum circuit breaker according to claim 3,
characterized in that the fastening means, which fixes the fixing member to the mold protruding portion (20a) located on a periphery of the floating potential metal (11), is an inspection bolt (22),
wherein the inspection bolt (22) and an inspection insert nut (23), which pairs with the inspection bolt (22), fix the fixing member (19) at a position separated from the floating potential metal (11) by a predetermined distance, and
wherein the inspection bolt (22) and the inspection insert nut (23) are electrically insulated from each other via an insulating member (24).
The vacuum circuit breaker according to claim 6, comprising:
a pressure monitoring device (25) which is connected to the inspection bolt (22) and which detects a potential increase of the floating potential metal (11) when an internal pressure in the vacuum valve (1) increases; and

a determination device (26) which determines whether or not the internal pressure in the vacuum valve (1) is abnormal from a detection signal detected by the pressure monitoring device (25).
The vacuum circuit breaker according to claim 7,
characterized in that the pressure monitoring device (25) is constructed of: a connection line (25a) which is connected to at least one of the inspection bolt (22) and the inspection insert nut (23); a plurality of insulating components (25b1, 25b2) which are connected partially in series to at least one of the inspection bolt (22) and the inspection insert nut (23) via the connection line (25a) ; and a potential measuring device (25c) which is connected between the plurality of insulating components (25b1, 25b2), and
wherein, of the plurality of insulating components (25b1, 25b2) which are connected partially in series to at least one of the inspection bolt (22) and the inspection insert nut (23), the insulating component (25b2), which is different from the insulating component (25b1) located close to the inspection bolt (22) and the inspection insert nut (23), is connected to a potential fixed point (25d).
The vacuum circuit breaker according to claim 6,
characterized in that the inspection bolt (22a, 22b, 22a1, 22a2, 22a3) and the inspection insert nut (23a, 23b, 23a1, 23a2, 23a3) are plurally arranged in a peripheral direction or in the axial direction of the floating potential metal (11).
The vacuum circuit breaker according to claim 9,
characterized in that the plurality of inspection insert nuts (23a, 23b, 23a1, 23a2, 23a3) arranged in the peripheral direction or in the axial direction of the floating potential metal (11) are arranged in such a way as to be different from each other in a distance from the floating potential metal (11) .
The vacuum circuit breaker according to claim 1,
characterized in that the fixing member (19, 19a, 19b) is plurally arranged, and
wherein the respective fixing members (19, 19a, 19b) extend over the mold part (1A) of the vacuum valve (1) and over the operating mechanism part (4) and are fixed to a plurality of mold protruding portions (20a, 20b, 20c, 20a1, 20a2, 20a3), which are provided on a side surface of the mold part (1A) of the vacuum valve (1) in such a way as to protrude, and to the operating mechanism part (4) with fastening means (21a, 21b, 21c, 21d).