JP2905330B2 - Disconnector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disconnecting switch, and more particularly to a disconnecting switch installed in a power generation main circuit.

[0002]

2. Description of the Related Art FIG. 5 is a cross-sectional view of a conventional disconnector shown in, for example, the Electric Criticism May 1984 issue.
1 is a grounding tank as a container, 24 is a fixed electrode, 22 is a substantially cylindrical fixed contact attached to the fixed electrode, 29
Is an arc contact mounted on the fixed contact 22 coaxially with the fixed contact 22, 23 is a movable electrode, 26 is a movable contact having a hollow portion 40, and is mounted on the movable electrode 23 coaxially with the fixed contact 22. . 9 is an opening at the tip of the movable contact 26,
25 is a piston attached to the movable contact 26, 6 is a cylinder attached to the movable electrode 23, 7 is a negative pressure chamber composed of the cylinder 6 and the piston 25, 26a is a hollow portion 40 of the movable contact 26. A communication hole communicating with the negative pressure chamber 7;
Reference numeral 7 denotes an operation rod.

Next, the operation will be described. At the time of opening,
The operation rod 27, the piston 25,
The movable contact 26 is moved in conjunction with it to expand the volume of the negative pressure chamber 7 and reduce the pressure P ₁ of the negative pressure chamber 7 to the gas pressure P ₀ in the ground tank.
ΔP (ΔP = P ₀ −P ₁ ). Due to this gas pressure difference ΔP, a suction flow of the insulating gas is formed in the opening 9 at the tip of the movable contact 26, and this gas flow is blown to the arc 30 generated between the arc contact 29 and the movable contact 26 at the time of opening. Effectively shut off.

[0004]

Since the conventional disconnector is constructed as described above, it is inconvenient because a special insulating gas such as SF ₆ is used as the insulating medium, and the disconnection resistance due to gas leakage is low. There is a problem when reliability is particularly required in view of the concern of voltage performance degradation.

The present invention has been made to solve the above problems , and has as its object to obtain a highly convenient disconnector which does not cause a problem due to gas leakage.

[0006]

In the disconnector according to the present invention, air is introduced into the container as an insulating medium, and the air at the tip of the movable contact is opened by the negative pressure in the negative pressure chamber during the opening operation. The suction flow speed is set to 10 m / S or more.

[0007]

In the disconnecting device according to the present invention, during the opening operation, the air flowing at a high speed through the opening at the tip of the movable contact causes a gap between the tip of the arc contact and the opening at the tip of the movable contact. Extinguishes the small current arc that appears , and
A long-life disconnector capable of small current opening operation can be obtained.
In the closing operation, if the air is discharged at high speed at the opening at the tip of the movable contact , the air can be injected without much thermal damage due to the pre-arc of the inrush current by the air. A long life disconnector that can be opened and closed is obtained.

[0008]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG.
, 1 to 29 are the same as or equivalent to the conventional example. Here, air is charged into the grounding tank 1 as an insulating medium. Then, the diameter of the cylinder 6 is increased,
The flow rate of the opening 9 was increased by reducing the diameter of the zero and increasing the output of the operating device that drives the operating rod 27. The movable contact 26 and the arc contact 29 use an arc-resistant metal material such as a copper chromium alloy or a copper tungsten alloy.

Next, an operation for interrupting a small current when the disconnector is opened will be described with reference to FIG. The operation is basically the same as the conventional example, but FIG. 2 shows a state during the opening operation. An operating device (not shown) drives the operating rod 27 rightward in the figure at a higher speed than in the conventional example. When the tip of the arc contact 29 is separated from the movable contact 26, the arc 30 is released by a small current flowing between the two before the opening.
Occurs. At this time, the pressure in the negative pressure chamber 7 is reduced, so that air flows from the opening 9 at the tip of the movable contact 26 through the hollow portion 40 and the communication hole 26a as shown by the arrow in the drawing. Is sucked faster than in the conventional example. Therefore, the high-speed airflow on the surface of the opening 9 at the tip of the movable contact 26 extinguishes the arc 30. In addition, regarding the flow velocity of this air flow, the voltage of the power generation main circuit (26 kV or less, usually around 20 kV)
It has been found from the results of the interruption experiments and the like in consideration of the above that a flow velocity of 10 m / S or more is required near the surface of the opening 9 of the tip end of the movable contact 26 in order to achieve the small current interruption. In this experiment, it was found that a flow rate several times larger than the current flow rate is desirable for interrupting the current, but the flow rate is determined in terms of design due to restrictions on the cost and dimensions of the operating device. Normally, the arc is extinguished by an opening degree of about 50%. Therefore, in this embodiment, 10 m /
The arc is extinguished so that a flow rate of S or more can be output for a predetermined time or more. The operating rod 27 is driven at a predetermined speed (usually 1 to 3 meters per second) to achieve this flow rate.

On the other hand, the operation of turning on the inrush current of the transformer when the disconnector is closed will be described with reference to FIG. FIG. 3 shows a state during the closing operation. When the operating rod 27 is driven at a high speed to the left in the drawing at the same speed as the opening operation, in this case, the negative pressure chamber 7 is compressed and pressurized. As a result, air is rapidly discharged from the communication hole 26a through the hollow portion 40 of the movable contact 26 to the distal end opening 9 as shown by the arrow in the drawing.
26 The air flow generated between the tip opening 9 and the tip of the arc contact 29 removes large arc heat (arc energy) due to the pre-arc 31 from the local part. There is no possibility that such an impossibility of injection such as welding or firm contact between the two contacts is caused. As described above, the movable contact 26 and the arc contact 29 whose surfaces are exposed to the arc at the time of current switching are formed of an arc-resistant metal material, and do not deteriorate over time. Because of the shut-off and closing, the wear per operation is incomparably small compared to the conventional one. According to experiments, for example, parts must be replaced electrically for small currents in the power generation main circuit. It is possible to achieve 10,000 times of opening and closing without using it.

Embodiment 2 FIG. Another embodiment is shown in FIG. This figure is an enlarged view of parts corresponding to the arc contact 29 and the movable contact 26 of the embodiment of FIG. The same reference numerals as those in FIGS. 1, 2 and 3 indicate the same or corresponding parts except 26 in the figure, and therefore the description thereof will be omitted. In FIG. 4, reference numeral 26 denotes a substantially cylindrical movable contact which is connected to the operating rod 27 via the piston 25 and is coaxially arranged inside the fixed contact 22. And a communication hole 26a similar to that shown in FIG. 1 is provided in the base. FIG.
During the opening operation in the same manner as described above, the operating rod 27 is driven at a high speed in the right direction in the drawing, so that the distal end of the arc contact 29 has the protruding opening 26b as described in FIG.
At the time of the separation, a high-speed airflow is generated in the creeping direction near the inner peripheral surface of the projecting opening 26b. FIG. 4 is a detailed view of FIG. 4. Compared to FIG. 2, in FIG. 4, the arc 33 between the arc contact 29 and the protruding portion 26b is shown because of the bell mouth shape of the protruding opening 26b. As shown by the middle arrow, the air flow is substantially at a right angle, and the arc extinguishing ability is further improved. Note that, in these embodiments, the grounding tank 1 is air-tight and air-tight, but may be ventilated with the air.

[0012]

As described above, according to the present invention, air is used as an insulating medium, and a negative pressure chamber is provided by a piston and a cylinder. the tip air above the wind speed 10 m / s at the opening near creeping of the is configured to flow into, and has a small current open pole performance of multiple, structure is simple, there is no leakage problems of the insulating gas There is an effect that a reliable and convenient disconnector can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a disconnector according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state during an opening operation by the disconnector of FIG. 1;

FIG. 3 is a sectional view showing a state during a closing operation by the disconnector of FIG. 1;

FIG. 4 is a partial sectional view of a disconnector showing another embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional disconnector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Grounding tank 6 Cylinder 7 Negative pressure chamber 9 Opening 22 Fixed contact 25 Piston 26 Movable contact 26b Projection opening

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-247928 (JP, A) JP-A-56-9636 (JP, U) JP-A-50-59564 (JP, U) JP-A 55-96 117736 (JP, U) 1994 IEEJ Power / Energy Division Conference Papers (Paper I), published July 5, 1992, pp. 401-406, hot gas flow when large currents were interrupted (58) Fields investigated (Int. Cl. ⁶ , DB name) H01H 33/91

Claims (1)

(57) [Claims] 1. A fixed contact formed substantially in a cylindrical shape in a container, a cylindrical movable contact coaxially movable with the fixed contact, and a piston and a cylinder interlocked with the movable contact. In the suction arc-extinguishing type disconnector having a rated voltage of 26 kV or less, an arc is sucked into the inside of the opening at the tip of the movable contact, and the container is filled with air or air. And a pressure of the negative pressure chamber during the opening operation so that the flow rate of air suction near the opening surface becomes 10 m / S or more.