JP2638163B2 - Vacuum interrupter vacuum drop detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a degree of vacuum reduction using a fluorescent interrupt collector of a vacuum interrupter.

B. Summary of the Invention This invention is a vacuum interrupter using a fluorescent interrupter of a vacuum interrupter, in which a linear fluorescent resin member is wound around the outer periphery of a vacuum vessel,
By guiding the light beam detected by the fluorescent resin member to the detector via an optical fiber cable, the area to be focused can be enlarged, and the light beam from any direction can be collected. A fluorescent light beam that is hardly attenuated in the fiber is used to reliably detect a decrease in vacuum degree.

C. Prior Art Originally, vacuum interrupters have a longer life, both electrically and mechanically, than other switchgear, and require little maintenance. However, in addition to a decrease in the degree of vacuum accompanying an increase in the number of cuts, the degree of vacuum may decrease, though very rarely, due to a vacuum leak from a bellows or an airtight joint. The vacuum interrupter (current interrupting section) has a reduced degree of vacuum, so that the interrupting performance as a vacuum interrupter is reduced, and as a result, interrupting is impossible. Therefore, it is required to check the degree of vacuum regularly or constantly. Moreover, the vacuum interrupter is desired to be able to accurately and simply inspect the degree of vacuum in an energized state after the vacuum interrupter is assembled with the operation mechanism to constitute a vacuum circuit breaker.

In order to satisfy the above demand, there is a vacuum interrupter vacuum drop detecting device described in JP-A-62-43530. The invention described in the above publication is provided with a metal intermediate shield insulated from the electrode, when the degree of vacuum is reduced between the intermediate shield and either the fixed side or the movable side system potential member, Forming a first vacuum gap for discharging in a vacuum region capable of being cut off, detecting a discharge light when the discharge is performed in the first vacuum gap with a light receiving portion provided on the outer periphery of the glass insulating cylinder, and detecting the light with an optical fiber; And when the detector detects the discharge light in the first vacuum gap, a cutoff command is transmitted. Then, when the degree of vacuum of the vacuum interrupter decreases during energization, discharge starts in the first vacuum gap (long gap) provided on either the fixed side or the movable side before reaching the non-shutoff area. . At this time, no discharge occurs in the second vacuum gap (short gap), and the second gap is not triggered by the discharge in the first vacuum gap and does not discharge. By discharging in the first vacuum gap, the fluorescent light or direct light of the cylindrical body due to the discharge is detected by the light receiving unit and guided to the detector by an optical fiber. As a result, a decrease in the degree of vacuum is immediately detected by the detector. Since the detection is performed at the stage where only the first vacuum gap is discharging, the current can be cut off by opening the electrode immediately after the detection.

D. Problems to be Solved by the Invention Since the discharge light generated in the vacuum vessel is locally generated, when the light is detected by the light receiving unit and guided to the optical fiber, the discharge light may not be incident on the light receiving unit. . In addition, a lens is usually attached to the light receiving unit, and a means for collecting the discharge light with the lens and introducing it to the optical fiber is adopted.However, if discharge does not occur within a range where the lens can receive light, There is a problem that a large amount of discharge light cannot be introduced into the optical fiber. Further, there is a problem that the discharge light is relatively easily attenuated in the optical fiber.
For these reasons, there is a disadvantage that it is not possible to reliably detect a decrease in the degree of vacuum of the vacuum interrupter.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus for detecting a decrease in the degree of vacuum of a vacuum interrupter, in which a large light-collecting area is ensured to obtain a large amount of discharge light and convert it to a fluorescent light.

E. Means for Solving the Problems According to the present invention, a vacuum vessel is formed by closing both ends of a glass insulating cylinder with an end plate, and a fixed electrode rod is introduced into this vacuum vessel from one end plate in an airtight manner, and A movable electrode rod that can freely move toward and away from the fixed electrode rod from the end plate is air-tightly introduced through a bellows, and a pair of inner and lower ends of the two electrode rods is provided with a fixed and movable electrode that can freely contact and separate from each other. An apparatus for detecting a decrease in the degree of vacuum of a vacuum interrupter capable of opening and closing a system electric circuit, wherein a metal intermediate shield surrounding at least an outer periphery of the electrode is provided in a vacuum vessel insulated from the electrode. A linear fluorescent resin member is coaxially wound around the outer periphery of the tube in a coaxial direction and wound a plurality of times, and the outer periphery of the vacuum container is molded, and one end of the fluorescent resin member is discharged by the vacuum container. Focus the light Process so that light does not leak and optically couple one end of the optical fiber cable to the other end, guide the other end of the optical fiber cable to the detector, and cut off when the detector detects a discharge light beam in the vacuum vessel Is transmitted.

F. Function When a discharge is generated in the vacuum vessel to generate a discharge light, the light is collected by the linear fluorescent resin member. At the time of this light condensing, since the peripheral light area of the fluorescent resin wound around the outer periphery of the vacuum container is large, the light condensing amount increases, and the discharge light is converted into fluorescent light and supplied to the optical fiber. As a result, a shutoff command can be reliably issued, and the current can be interrupted by opening the electrodes.

G. Embodiment The present invention will be described below based on an embodiment shown in the drawings.

FIG. 1A is a structural explanatory view showing an embodiment of the present invention, wherein 1 is a vacuum interrupter, 2 is an intermediate shield, and this intermediate shield 2 is a system potential member (system) such as a fixed electrode rod 4a or a movable electrode rod 4b. (A member having the same potential as the electric circuit). 3a and 3b are auxiliary shields, 40 is a bellows, 41a and 41b are metal end plates, and 42a and 42b are electrodes. Also 43
a and 43b are insulating cylinders, 44 is a sealing fitting, and metal end plates 41a and 41b
Together, they constitute a vacuum container. The auxiliary shield 3a has a reduced axial length, and a fixed end plate of the intermediate shield 2.
Ends of 41a side to protrude sufficiently long in the axial direction than the end of the auxiliary shield 3a, facing directly fixed electrode rod 4a through the first vacuum gap l ₁ without the protruding portions sandwich the auxiliary shield 3a It is configured to be. Gap length of said first vacuum gap l ₁ is the length of discharge cutoff possible vacuum region A when the degree of vacuum decreases, the maximum distance between the different potential member of the vacuum interrupter 1.

When electrons fly between the different potential members, they fly in a direction perpendicular to the electric potential potential line. Therefore, the distance described here strictly means the flight distance of the electrons. l ₂ is the second vacuum gap, a l _1> l ₂ relationship.

45a and 45b are linear fluorescent resin members which are wound a plurality of times in close contact with the outer surfaces of the glass insulating cylinders 43a and 43b and serve as a light collector, which will be described in detail later. One end of each of the members 45a and 45b is an optical fiber cable. Four
The other end is connected to one end of 6a, 46b, and the other end is connected to a detector 47 in which a photoelectric converter (not shown) including a phototransistor or the like is housed. The other ends (ends not connected to the optical fiber) of the fluorescent resin members 45a and 45b are formed so as to be reflected by, for example, Ag plating so that light does not leak. The detector 47 outputs a signal only when a light beam condensed by the fluorescent resin member 45a is input, that is, only when a degree of vacuum is reduced in a vacuum region that can be cut off.
Supply to 48. The shutoff command unit 48 issues an alarm when the signal is present to notify that the degree of vacuum has decreased.

In FIG. 1A, reference numeral 49 denotes a molding member. If the vacuum container is covered with the molding member 49, the fluorescent resin members 45a, 45
Unnecessary rays do not enter b. 50 is a capacitor for bypassing discharge energy, and 51 is a load.

Here, the linear fluorescent resin members 45a and 45b serving as the light collector shown in FIG. 1B will be described. FIG. 1B is a view when the vacuum vessel is omitted. These members 45a and 45b are made of acrylite (PMMA), polycarbonate (PC), polystyrene (P
S) is made of a linear material in which a fluorescent dye is mixed into a transparent plastic such as S). Optical fibers 46a and 46b are connected to one end of the members 45a and 45b, and the other end is made so that light does not leak. A silver-plated reflector is provided.

The linear fluorescent resin members 45a, 45b configured as described above are wound around the glass insulating cylinders 43a, 43b a plurality of times and arranged.
Now, when a discharge occurs in the vacuum vessel, the direct light and the diffused light at that time are incident on the members 45a and 45b as shown in FIG. The total reflection is repeated to reach the end where the optical fibers 46a and 46b are connected. Then, the fluorescent light is transmitted through the optical fibers 46a and 46b.
And reaches the detector 47. At this time, since the light is a fluorescent light, there is not much attenuation by the optical fibers 46a and 46b.

 Next, the operation of the above embodiment will be described.

When the degree of vacuum of the vacuum interrupter 1 interposed in the system electric path is normal, no discharge occurs between the _first and second vacuum gaps l ₁ and l _2, so that no signal is sent from the detector 47. Now vacuum is lowered, it begins to discharge at a first vacuum gap l ₁ between the intermediate shield 2 and the fixed electrode rod 4a. The reason for this is that, in the region around 10 ⁻² mmHg of the Passien curve shown in FIG. 2, the discharge characteristic is such that the gap length is large, and the first vacuum gap l ₁ is formed inside the vacuum interrupter 1. since there is a maximum distance between the different potential member, initially it begin to locally discharged at the first vacuum gap 1 _1. A discharge light beam or a direct light beam of the discharge to the insulating cylinder 43a (this cylindrical body is made of glass) due to the discharge at this time is incident on the linear fluorescent resin member 45a. The light beam incident on the member 45a is converted into a fluorescent light beam by the member, is incident on the optical fiber, and is supplied to the terminal A of the detector 47 via the optical fiber 46a by repeating total reflection as described above. When the received light beam is applied to the terminal A of the detector 47, the detector 47 supplies a signal to the cutoff command unit 48. When a signal is supplied from the detector 47, the shutoff command section 48 issues an alarm to the output and is used to determine that the degree of vacuum has decreased. Note that the terminal B of the above cases the detector 47 but is input ray does not arrive, when the light beam arrives at the terminal B only when the second vacuum gap l ₂ is discharged.
The second vacuum gap l ₂ is discharged is when the degree of vacuum is lowered until the cut-off impossible, the terminal A of the detector 47, B
In both cases, when a light ray arrives, the fact is notified using, for example, an auxiliary switch.

The following table summarizes the operation states of the detector 47 described above.

In the above-described embodiment, the gap having the maximum distance is provided between the fixed electrode rod 4a and the intermediate shield 2. In the above-described embodiment, the fixed side and the movable side are prevented from flashing. Alternatively, if it is one of the movable sides, not only the electrode rod but also the intermediate potential between the system potential member such as the metal end plates 41a and 41b and the intermediate shield member 2 at the time when the degree of vacuum is low and the cutoff is possible. A configuration in which a first vacuum gap that discharges in the region may be provided. In the above embodiment, detection can be performed not only in the closed state but also in the open state. In this case, it is necessary to provide the first vacuum gap on either the fixed side or the load side of the load. There is. In the above embodiment, the case where the discharge light in the first and second vacuum gaps is detected has been described.
It is sufficient to detect the discharge light in the vacuum gap. This is because the leak is often slow at the beginning of the leak when the degree of vacuum is lowered.

H. Effect of the Invention As described above, according to the present invention, the area between the intermediate shield and either the fixed side or the movable side system potential member when the degree of vacuum is low and the cutoff is possible Since the first vacuum gap that discharges is formed at the initial stage (high vacuum) when the degree of vacuum decreases, discharge occurs on either the fixed side or the movable side. Since the light beam due to this discharge was detected by the fluorescent resin member provided on the outer periphery of the glass insulating cylinder,
The light condensing area increases as compared with the conventional case where the light is condensed using a lens. In addition, compared to using a lens, the directivity is small and any light rays in the circumferential direction of the vacuum vessel can be circulated, and the structure is simple (the structure using the lens is complicated because it is necessary to focus on an optical fiber). ). Further, since the discharge light is converted into a fluorescent light by the fluorescent resin member, the decrease in the degree of vacuum can be reliably detected without attenuation in the optical fiber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A and FIG. 1B are explanatory diagrams showing the configuration of an embodiment of the present invention and details of a main part, and FIG. 2 is a diagram showing the degree of vacuum and discharge start when the vacuum gap length is different. FIG. 4 is a curve diagram illustrating a relationship with a voltage. 1 ... Vacuum interrupter, 2 ... Intermediate shield, 3a, 3b
…… Auxiliary shield, 4a …… Fixed electrode rod, 4b …… Movable electrode rod, 43a, 43b …… Insulated cylinder, 45a, 45b …… Fluorescent resin member, 46
a, 46b …… Optical fiber cable, 47 …… Detector, 48 ……
Interruption command section.

Claims (1)

(57) [Claims] 1. A vacuum vessel is formed by closing both ends of a glass insulating cylinder with end plates, into which a fixed electrode rod is airtightly introduced from one end plate and from the other end plate to a fixed electrode rod. A movable electrode rod which can be freely approached and separated is air-tightly introduced via a bellows, and a pair of inner and lower ends of the electrode rods are provided with fixed and movable electrodes which can be freely contacted and separated from each other. An apparatus for detecting a decrease in the degree of vacuum of a vacuum interrupter capable of opening and closing a system electric circuit, which is provided by insulating a metal intermediate shield surrounding the outer periphery of the electrode with respect to the electrode, comprising: A linear fluorescent resin member is coaxially wound and wound a plurality of times in close contact, and the outer periphery of the vacuum container is molded, and one end of the fluorescent resin member is a light beam that condenses discharge light generated in the vacuum container. So as not to leak In addition, one end of the optical fiber cable is optically coupled to the other end, the other end of the optical fiber cable is guided to a detector, and a cutoff command is transmitted when the detector detects a discharge light beam in the vacuum vessel. Vacuum interrupter vacuum drop detector.