JPS6128205B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a three-phase capacitor, and more particularly to a three-phase capacitor that prevents a major accident such as a short circuit between phases even if an accident occurs in a group of star-connected capacitor elements.

Conventionally, many three-phase capacitors have been used in high-voltage circuits. This three-phase capacitor is constructed by housing a group of star-connected capacitor elements inside one case. If an accident occurs in a part of the capacitor element group in such a case, this accident will affect other phases, leading to a major accident such as a short circuit between phases, and the energy of the excessive short circuit current will decompose the insulating oil and cause a large amount of There have been reports of gas being generated, increasing the pressure inside the case and causing the case to explode. This type of pressure detection device is described in Japanese Unexamined Patent Publication No. 49-57357 and Japanese Unexamined Patent Publication No. 51-10353, but these devices have the disadvantage that it takes time to detect pressure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a three-phase capacitor that prevents the spread of accidents by speeding up pressure detection time and is equipped with a pressure detection device that has a simple structure.

The internal pressure detection device of the present invention is arranged so that when the tank expands, the contact points approach each other and come into contact with each other, thereby shortening the pressure detection time and preventing the spread of an accident. be.

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

1 is a capacitor element arranged in three blocks for each phase, and each phase is connected in a star shape as shown in the figure. 2 is a metal plate inserted between each phase,
It is electrically connected to a tank 4 housing the capacitor element 1 and grounded. 3 is an internal pressure detection device inserted into the center of the element inside the tank. Although not shown in the drawings, it goes without saying that sufficient insulation is provided between the element 1, the metal plate 2, and the internal pressure detection device 3.

The detailed structure of the internal pressure detection device 3 will be explained with reference to FIG. A switch frame 20 is arranged inside the tank. The springs 20A and 20B are interposed between the left and right tanks 4 and the switch frame 20. A pair of movable rods 21A, 21B insert springs 20A, 20B from the inner surfaces of the left and right tanks and extend into the switch frame. First and second arms 22, 23 are attached to the ends of a pair of movable rods, which are arranged in correspondence with each other within the switch frame.

One end 22A of the first arm 22 is bent in a direction perpendicular to the axial direction of the movable rod 21A, that is, in a downward direction, and a first contact 24 is attached thereto. One end 22B of the second arm 23 is connected to one end 22B of the first arm 22.
A second contact 25 is attached which is bent in the opposite direction to A, that is, upward, and which comes into contact with and separates from the first contact 24. The first contact 24 and the second contact 25 are connected to the tank 4
When the movable rods 21A and 21B move in the directions A and B, energy is accumulated while pulling the springs 20A and 20B, and both contacts 24 and 25
contact, but when no force is applied in the directions of arrows A and B, the stored energy of the springs 20A and 20B is released and they move in the direction opposite to the directions of arrows A and B, and both contacts separate. The connection and disconnection of both contacts 24 and 25 is transmitted to the outside through a lead wire 26 connected to both arms 22 and 23, and the lead wire 26 that disconnects the three-phase capacitor circuit or issues an alarm is connected to both arms 22 and 23. It extends to the outside via a bushing 27 arranged in the tank 4.

Next, the operation of the internal pressure detection device 3 of the present invention will be explained. While the tank 4 moves from the solid line to the position indicated by the chain line due to gas pressure generated due to an internal accident within the tank, both movable rods 21A and 21B move in the direction of the arrow while pressing the springs 20A and 20B. Then, both contacts 24 and 25 move in a direction approaching each other, and finally both contacts 24 and 2
5 makes contact, and disconnects the circuit of the three-phase capacitor 1 via the lead wire 26 or generates an alarm, thereby preventing the accident from spreading. When the tank 4 expands, this internal pressure detection device 3 detects both contacts 2.
4 and 25 move toward each other, and both contacts come into contact before tank 4 reaches the chain line from the solid line.In an initial internal accident, the expansion of tank 4 can be detected while the expansion is small, so it is possible to prevent the accident from expanding. It can be prevented. Further, since both contacts 24 and 25 are in contact with each other in a direction of pressing, contact failure does not occur, and an accident can be reliably detected.

As described above, according to the internal pressure detection device of the present invention, an internal accident can be detected quickly, so that the spread of the accident can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a three-phase capacitor showing an embodiment of the present invention, and FIG. 2 is an internal pressure detection device.
FIG. 2 is a sectional view taken along the - line in FIG. 1; 1... Capacitor element, 2... Metal plate, 3...
Internal pressure detection device, 4...Tank, 21A, 21
B...Movable rod, 22, 23...Arm, 24...
1st contact, 25...2nd contact.

Claims (1)

[Claims] 1. A three-phase capacitor configured by connecting capacitor element groups for each phase in a star shape, and a metal plate between the capacitor element groups for each phase, and the internal pressure of a tank that houses the capacitor element groups for each phase. The device is equipped with an internal pressure detection device that detects when the pressure has exceeded a predetermined value. At least a pair of movable rods extending from the tank into the switch case are arranged correspondingly, and a first arm and a second arm are attached to the tips of the movable rods inside the switch case,
One end of the first arm is bent in a direction perpendicular to the axial direction of the movable rod, and a first contact is attached, and one end of the second arm is bent in a direction opposite to one end of the first arm, and the first contact is brought into contact with and separated from the first contact. A three-phase capacitor characterized in that it is configured by attaching a second contact point.