JPH0251816A - Gas-blast disconnector - Google Patents

Abstract

PURPOSE:To shorten the distance between a fixed electrode and a shield and make the whole small-sized by feeding the inter-electrode discharge arc current via the fixed electrode side shield in the opening process in the fixed electrode side shield buried with a resistor in an insulator or stuck with a film resistor on the insulator. CONSTITUTION:A fixed side shield is buried with a resistor 28 in an insulator 27, a metal electrode 29 is connected at the tip section of this fixed side shield. When the charging current is cut off, the current at the time of reignition flows through a conductor 4, a fixed electrode 6, the resistor 28, the metal electrode 29, a reignition arc 25, a movable electrode side arc-resistant electrode 12, a movable electrode 9, an excitation contact piece 13 and a conductor. The overvoltage can be suppressed low due to the circuit loss by the resistor 28. The axial direction length can be made about a half as compared with an independent resistor and a shield connected electrically, thus the whole can be made small-sized.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a gas disconnection in which a sealed container is filled with an arc-extinguishing insulating medium, and a movable and fixed contact can be connected to and separated from the inside. Concerning vessels.

(Prior art) Conventionally, as an example of this type of gas disconnector, the
What is shown in Publication No. 8031 and Japanese Patent Publication No. 80-42570 is publicly known, and FIGS. 7 and 11 are diagrams for explaining this.

In Fig. 7 and Fig. 11, 1 is a metal tank;
is SF6 gas sealed in a metal tank 1, 3 is a spacer, 4 is a conductor that leads to the fixed side terminal of the disconnector, 5 is a conductor that leads to the movable side terminal of the disconnector, 6 is a fixed electrode, and 7 is the metal on the fixed electrode side. 8 is a resistor inserted between the fixed electrode 6 and the shield 7, 9 is a movable electrode, 10 is an arc-resistant electrode on the fixed electrode side, 11 is a current-carrying contact on the fixed electrode side, and 12 is an arc-resistant electrode on the movable electrode side. 13 is a current-carrying contact on the movable electrode side; 14 is a metal shield on the movable electrode side; and 15 is an insulator for driving the movable electrode 9.

In the disconnector shown in FIG. 7, the insulator 15 is connected to an operating mechanism (not shown), and the operating mechanism performs opening and closing operations.

Generally, a disconnector is required to interrupt charging current on a short power transmission line. If the distributed capacitance and distributed inductance of power transmission lines, transformers, etc. are approximately represented by lumped capacitance or lumped inductance, and the charging current cutoff circuit of the power transmission line is represented by an equivalent circuit, the result will be as shown in FIG. 8, for example.

16 is the power supply voltage, 17 is the short circuit impedance, 18 is the capacitance of the transformer, power supply side power transmission line, etc., 1 is the inductance of the power supply side power transmission line, 20 is the capacitance of the load side power transmission line, and 21 is the inductance of the load side power transmission line. , 22 is a disconnector.

The insulation recovery characteristics between the arc-resistant electrode 12 on the movable electrode side and the metal shield 7 in FIG. 7 are as shown in FIG. 9. When opening a circuit as shown in FIG. 8 with a new circuit device having such characteristics, a voltage waveform as shown in FIG. 10 is obtained. In Fig. 10, 23 is the voltage waveform at point a'' in Fig. 8, and 24 is the voltage waveform of the power supply voltage.The difference between the curves 23 and 24 is the voltage between the poles of the disconnector.Explain this relationship. Then, for example, at point A, the arc-resistant electrode 12 on the movable electrode side and the arc-resistant electrode 10 on the fixed electrode side open, and then when the tip of the movable arc-resistant electrode 12 comes out from inside the shield 7, the current becomes small 1.
Therefore, the current is interrupted at point B and the capacitance 2 on the load side is
The power supply voltage at this time remains at 0, and the voltage between electrodes increases as the power supply voltage changes. When the interelectrode voltage exceeds the insulation recovery voltage, it will be re-ignited at the 0 point.

However, since the current is small, it is immediately cut off and the source voltage remains in the load capacitance 20. In this way, restriking is repeated, and as the insulation recovery voltage rises, the inter-electrode voltage at the time of restriking also increases, but if the insulation recovery voltage exceeds the inter-electrode voltage, the repeated restriking stops and the interruption is completed. . No.
Re-ignition points C, D, E, F, G, and H in Fig. 10 are C, D shown in Fig. 9.

This corresponds to the distance between poles of E, F, G, and H. 11f above
Ignition occurs between the tip of the shield 7 and the arc-resistant electrode 12 on the movable electrode side.
Therefore, a restriking arc 25 is formed as shown in FIG. 11.

Now, even with the configuration shown in Figure 7, if surge suppression is not necessary,
In other words, in the case of a disconnector in which the resistor 8 inserted between the fixed electrode 6 and the shield 7 is a metal conductor, the gap between the electrodes, that is, the arc-resistant electrode 12 on the movable electrode side and the shield 7
When restriking occurs between is larger as the inter-electrode voltage when the disconnector is re-ignited is larger. This overvoltage may threaten the insulation of the circuit breaker itself or other equipment adjacent to it. Therefore, in order to reduce the overvoltage at the time of restriking, a resistor 8 is provided in FIG. The current is passed through the path of the electrode 9, current-carrying contact 13, and conductor 5, and the overvoltage is suppressed to a low level by utilizing the circuit loss caused by the resistor 8.

(Problems to be Solved by the Invention) In FIG. 7, a voltage is applied to the resistor 8 when suppressing the high frequency overvoltage at the time of restriking.

In order for the resistor 8 to withstand this voltage, the resistor 8 must be made long. Therefore, the distance ML between one end (upper end) of the fixed electrode 6 and one end (lower end) of the shield 7 shown in FIG. 7 cannot be shortened, resulting in the disadvantage that the entire disconnector becomes larger. was there.

It is an object of the present invention to provide a gas disconnector that can shorten the distance tlL between the fixed electrode and the shield, thereby making the entire device smaller.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a fixed electrode having a contact and a contact of the fixed electrode in a metal tank filled with arc-extinguishing gas. In a gas disconnector comprising a fixed electrode-side shield provided to surround the fixed electrode and a movable electrode disposed opposite to the fixed electrode and capable of freely approaching and separating, the fixed electrode-side shield includes a resistor on an insulator. It is characterized in that it has an embedded structure or a structure in which a film resistor is attached to an insulator, and that an interelectrode discharge arc current is caused to flow through the fixed electrode side shield during the electrode opening process.

(Function) According to the present invention, by configuring the fixed electrode side shield as described above, it is possible to suppress the restriking overvoltage when the charging flow is interrupted.
Compared to conventional systems in which independent resistors and shields are electrically connected, the length in the axial direction can be reduced to about half, so the overall size can be reduced.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. 1 and 2 are half-sectional views for explaining a first embodiment of the present invention, which differs from the conventional example shown in FIG. 7 in the following points. Conventionally, a fixed-side shield consisting of a resistor 8 and a shield 7 provided to surround a contact 11 of a fixed electrode 6 is configured as follows. That is, a resistor 28 is embedded inside an insulator 27 as a stationary shield, and a metal electrode 29 is connected to the tip of the stationary shield.

Insulator 27 and resistor 28 forming the fixed side shield
For example, the resistor 28 is manufactured by molding and firing carbon-containing powder, and the insulator 27 is manufactured by molding this with epoxy resin.

In the gas disconnector shown in FIG. 1, the insulator 15 is connected to an operating mechanism (not shown), and the operating mechanism performs opening and closing operations.

Next, the operation of the first embodiment of the gas disconnector of the present invention configured as described above will be described. In Figure 1,
When cutting off the charging current, first, the arc-proof electrode 12 on the movable electrode side and the arc-proof electrode 10 on the fixed electrode side are opened, and then the tip of the arc-proof electrode 12 on the movable electrode side connects with the resistor 27 and the shield 28. When it comes out from the inside of the fixed side mold, it becomes a re-striking shape Q, and as shown in FIG. A restriking arc 25 occurs.

Then, the current at the time of restriking is the following: conductor 4 - fixed electrode 6 - resistor 28 - metal electrode 29 - restriking arc 25 - movable electrode side arc-resistant electrode 12 - movable electrode 9 - energizing contact 13 - conductor 5 flows through. Therefore, the overvoltage can be suppressed to a low level due to the circuit loss caused by the low antibody 28.

Disconnectors receive mechanical shock during closing and closing operations. In particular, when the fixed electrode 6 is turned on, the tip of the movable electrode 9 and the arc-resistant electrode 12 on the movable electrode side collide with the current-carrying contact 11 on the fixed electrode side and the arc-resistant electrode 10 on the fixed electrode side, respectively, so the impact is large. .

However, since the resistor 28 is embedded in the insulator 27, it can be easily made to withstand impact. When the electrode opening is completed, the movable electrode 9 and the movable electrode side arc proof 12 are housed inside the movable electrode side shield 14, and the movable electrode side shield 14 and the fixed electrode side shield consisting of the resistor 28 and the insulator 27 It must be able to withstand the voltage between poles.

These shields on the movable electrode side and the fixed electrode side also have the function of increasing the withstand voltage between the electrodes by bringing the electric field between the electrodes closer to each other equally. The fixed electrode side shield consists of a resistor 28 and an insulator 27, but when the resistance value required to suppress the overvoltage at the time of restriking is, for example, around 1Ω, the electric field between the electrodes is The effect of approximation to equality is almost the same as in the case of shields made of metal conductors.

Further, in FIG. 1, when the arc-resistant voltage 10 on the fixed electrode side does not exist and both energization and firing are performed in the current-carrying contact 11 on the fixed electrode side, and further when the arc-resistant electrode 12 on the movable side does not exist, The above effect can also be obtained in the same way.

In the first embodiment of the present invention described above, the fixed electrode side shield is composed of the insulator 27 and the resistor 28; therefore, the resistor 8 of the conventional example shown in FIG. 7 is unnecessary. . Therefore, the length in FIG. 1 can be made approximately half shorter than the length in FIG.
This allows the disconnector to be made smaller.

FIG. 3 is a diagram for explaining the second embodiment of the present invention, in which a fixed side shield consisting of a resistor 28 embedded in an insulator 27 has a resistor at its tip where restriking occurs. It is made of the same material as the body 28. This case can be applied when the arc current at the time of restriking is small and there is little damage to the tip of the fixed electrode side shield.

FIGS. 4 and 5 are diagrams for explaining a third embodiment of the present invention, in which the fixed electrode side shield is configured as follows. That is, a film resistor 28A is attached to the inner surface of the insulator 27A to constitute a fixed electrode side shield, and a gold G4 electrode 29 is connected to the film resistor 28A.

The operation of the third embodiment of the gas disconnector configured in this manner is the same as that of the first embodiment, so a description thereof will be omitted. In the explanation of the operation of the first embodiment (FIG. 1), the resistor 28 is simply replaced with the film resistor 28A.

In the embodiment shown in FIG. 4, the fixed electrode side shield is
Since the film resistor 28A is attached to the inner surface of the insulator 27A, the same effect as in the first embodiment can be obtained. That is, the resistor 8 in FIG. 7 showing the prior art becomes unnecessary. Therefore, the length shown in FIG. 4 can be made shorter than the length shown in FIG. 7, and the disconnector can be made smaller.

FIG. 6 is a diagram for explaining a fourth embodiment of the present invention, in which a film resistor 28A is attached to the surface of an insulator 27A on the metal tank 1 side.

[Effects of the Invention] According to the present invention described above, it is possible to provide a small gas disconnector that suppresses restriking overvoltage when charging current is interrupted.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view for explaining the first embodiment of the gas disconnector according to the present invention, FIG. 2 is a half-sectional view showing the gas disconnector shown in FIG. 1 in an open state, and FIG. FIG. 4 is a half-sectional view for explaining the second embodiment of the gas disconnector according to the present invention; FIG. 4 is a half-sectional view for explaining the third embodiment of the gas disconnector according to the present invention; The figure is a half-sectional view showing the open state of the gas disconnector shown in FIG. 4, FIG. 6 is a half-sectional view for explaining the fourth embodiment of the gas disconnector according to the present invention, and FIG. A half-sectional view for explaining an example of a gas disconnector, FIG. 8 is an approximate equivalent circuit diagram of charging current interruption in FIG. 7, and FIG. Fig. 10 is a voltage waveform diagram due to restriking at the time of charge/current break in Fig. 7, Fig. 11 is a half-sectional view showing the open state of the gas disconnector in Fig. 7, and Fig. 12 is a diagram of Fig. 7. FIG. 2 is an explanatory diagram of the restriking surge voltage of the gas disconnector. 1... Metal tank, 2... SF6 gas, 3...
Spacer, 4... Conductor, 5... Conductor, 6... Fixed electrode, 7... Fixed electrode side metal shield, 8... Resistor, 9... Movable electrode, 10... Fixed electrode side arc-resistant electrode, 11... Fixed electrode side current-carrying contact, 12... Movable electrode side arc-resistant electrode, 13... Movable electrode side current-carrying contact, 1
4... Metal roll on the movable electrode side, 15... Insulator, 25... Re-ignition arc, 26... Re-ignition surge voltage, 27... Insulator, 27A... Insulator, 28...
Resistor, 28A...Film resistor, 2...Metal electrodes.

Claims (2)

[Claims] (1) In a metal tank filled with arc-extinguishing gas, a fixed electrode having a contact, a fixed electrode-side shield provided to surround the contact of the fixed electrode, and a fixed electrode placed opposite to the fixed electrode. , and a movable electrode that can be freely connected and separated, the fixed electrode side shield has a resistor embedded in an insulator, and in the opening process, the interelectrode discharge arc current is transferred to the fixed electrode side shield. A gas disconnector that allows gas to flow through the gas. (2) In a metal tank filled with arc-extinguishing gas, a fixed electrode having a contact, a fixed electrode-side shield provided to surround the contact of the fixed electrode, and arranged opposite to the fixed electrode, and In a gas disconnector equipped with a movable electrode that can be freely connected and separated, the fixed electrode side shield has a structure in which a film resistor is attached to an insulator, and the interelectrode discharge arc current is passed through the fixed electrode side shield in the opening process. A gas disconnector that allows the flow to flow.