JPH0785611B2 - Ground switch for gas insulated switchgear - Google Patents

Description

The present invention relates to a ground switch for a gas insulated switchgear.

Gas insulated switchgear (hereinafter referred to as GIS) Consists of the circuit breaker body, disconnector body, bus conductor, etc., housed in a metal container at ground potential filled with insulating gas such as SF ₆ gas. In order to ground the safety of the main circuit, that is, the main body of the circuit breaker, the main body of the disconnector, and the energized main circuit formed by connecting and disconnecting the bus conductors, a grounding switch is provided at a required place.

By the way, the main circuit of the GIS has a sealed structure as described above, so the main circuit resistance to check whether or not it maintains the specified performance is measured by the terminals of each device such as the circuit breaker body and disconnector body. Can not be done directly from outside the container. For this reason, two ground switches are used and the voltage drop method is used.

However, when using a normal grounding switch, there is a problem that a value including the resistance of the grounding switch is derived.

On the other hand, if the main circuit grounding circuit (current injection circuit) and the main circuit voltage measuring circuit are separated, the resistance of the grounding switch is not included.

In order to satisfy this, it is conceivable that the movable part and the voltage measuring terminal of the voltage measuring circuit are connected by a flexible electric wire. However, according to this configuration,
When the number of times of opening and closing is increased, there is a problem that the connecting portion of the electric wire may be fatigue-ruptured, or the flexible portion may be entangled with other parts to hinder or cut the operation. Further, it is conceivable that the flexible electric wire is replaced by a sliding contact for the entire stroke of the opening / closing operation to constitute the voltage measuring circuit, but this has a drawback of accelerating the wear of the contact.

The present invention has been proposed in view of these points, and it is an object of the present invention to provide a grounding switch for GIS having a simple structure and a highly reliable structure that accurately measures the resistance of the main circuit and can ground the main circuit. To do.

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which GIS is a main body container in which an insulating gas 2 such as SF ₆ gas is filled at a predetermined pressure. Three
Is an end container that closes the open end of the container 1 and also serves as an operation mechanism container for the grounding switch 4 and the disconnector 5. Reference numerals 6, 7 and 8 are fixed contacts, sliding contacts and movable contacts of the earthing switch. The contactor 6 is supported by the container 3 through the main conductor 9 of the main circuit, the insulating spacers 10, and the three-phase collective mount 11 arranged in the direction orthogonal to the plane of the drawing. The sliding contactor 7 is supported by the container 3 via a contactor stand 12 and an attachment plate 13 made of an insulating material and having three phases.

The movable contactor 8 is operated by an operating unit (not shown) connected to an operating shaft 17 via a connecting rod 14 made of an insulating material, a three-phase mounting metal fitting 15, and an operating lever 16. Reference numeral 18 is a guide for guiding the mounting hardware 15 to move linearly and is arranged between the phases. 19 is a stopper.

In this embodiment, the movable contactor 8 has a cylindrical shape, and the voltage detection movable conductor 21 is housed inside the insulating cylinder 20. A tip 21a of the conductor 21 is slightly projected from the tip of the movable contact 8 so that the conductor 21 comes into contact with the fixed-side voltage detection contact 22. Reference numeral 23 is a pressure contact spring. An auxiliary movable contact 24 is attached to the other end of the conductor 21 and protrudes from the side surface of the movable contact 8 at a right angle. An auxiliary fixed contact 25 for receiving the contact 24 is attached to the mounting plate 13.

Reference numeral 26 is a grounding lead conductor, and 27 is a voltage detecting conductor, which are integrally embedded in an insulating spacer 28 made of an insulating material such as epoxy resin. Reference numeral 29 is a connection conductor for connecting the conductor 26 and the contact base 12, and 30 is a connection conductor for connecting the conductor 27 and the contact 25 for voltage detection.

The ground terminal 26a of the lead conductor 26 is connected to the mounting ground bar 32 of the three-phase package via the ground conductor 31. This bar 32 is a stand
A predetermined height is secured at 33.

34 is a shield, 35 is a main circuit lead-in conductor, and 36 is a main circuit lead-out conductor.

Further, although each component has three phases arranged in a direction perpendicular to the plane of the drawing, the description thereof is omitted.

The disconnector 5 has a fixed contactor, a sliding contactor, a movable contactor that slides into and out of contact with these, and is operated from the outside of the container 3, but the description thereof is omitted.

The grounding switch 4 opens when the disconnector 5 is closed and the main circuit conductors 35, 9, 36 are connected. In this state, the main circuit is energized.

The main circuit conductors 35 and 9 may be grounded by closing a circuit breaker (not shown), opening the disconnector 5, and then closing the grounding switch 4. As a result, the fixed contact 6, the movable contact 8, the sliding contact 7, the contact base 12, the connection conductor 29, the lead conductor 26, and the ground conductor.
After the three-phase short circuit via the main circuit grounding circuit by 31 and the grounding bar 32, grounding is performed via the container 3.

The auxiliary contacts 24 and 25 come into contact with each other when the earthing switch 4 comes close to the closed position, that is, when the movable contact 8 and the fixed contact 6 come in contact with each other, and the conductor 21 and the contact 22 come into contact with each other. Therefore, in addition to the grounding circuit, a main circuit voltage measuring circuit including the spring 23, the contact 22, the conductor 21, the contacts 24 and 25, the connecting conductor 30, and the conductor 27 is formed.

The main circuit resistance can be measured by, for example, a circuit breaker CB as shown in FIG.
, The grounding switches 4 and 4'that sandwich the measured sections a and b are closed, and the grounding conductors 33 and 33 'are removed from the grounding terminals 26a and 26a' of the lead conductors 26 and 26 ', respectively. Then, the measuring power source D is connected to pass a current, and the voltage between the voltage detecting conductors 27 and 27 'is measured by the voltmeter V.
Measure with to obtain resistance. In this way, the conductors 27,2
Since the voltage between 7'is the same as the voltage between the measured sections a and b, the resistance of the main circuit can be directly measured, so that the check with extremely high accuracy becomes possible. That is, it is possible to measure only the main circuit resistance without including the contact portions of the grounding devices 4 and 4'and the resistance of the lead conductor.

In this embodiment, since the flexible electric wire is not used, fatigue cutting due to the opening / closing operation and the trouble that the flexible electric wire is entangled with other parts do not occur. Also, the sliding portion is minimized, so that the wear is small. It also requires less operating force.

In the embodiment shown in FIG. 1, the open-circuit voltage detection conductor 21 and the contact
24 will be electrically insulated, and it is not unthinkable that voltage will be induced due to the induction from the main circuit voltage, but in reality, it is more grounded than the electrostatic capacitance to the main circuit. Against it is much less of a problem.

However, if this voltage is a concern, as shown in FIG. 3, a contact 37 for connecting the conductor 21 at the time of open circuit to the lead-out conductor 26 is provided, or a high resistance that does not interfere with the voltage measurement is always movable. It suffices to take measures such as connecting it to the contactor 8.

As described above, according to the present invention, the main circuit voltage measuring circuit is independently provided from the main circuit grounding circuit, and the latter is configured to be closed only near the former closed position. Not only can it be grounded, but only the main circuit resistance can be measured accurately, and flexible wires etc. are not required, and the structure can be simplified and a highly reliable GIS grounding switch can be obtained.

[Brief description of drawings]

1 is a side sectional view showing an embodiment of the present invention, FIG. 2 is an electric circuit diagram for explaining a main circuit resistance measuring method according to FIG. 1, and FIG. 3 is another embodiment of the present invention. It is a side section principal part figure shown. 6: Fixed contact, 7: Sliding contact 8: Movable contact, 20: Insulating cylinder 21: Movable conductor for voltage detection 22: Contact for voltage detection on fixed side 24: Auxiliary movable contact 25: Auxiliary fixed contact 26 : Lead-out conductor, 27: Voltage detection conductor 29, 30: Connection conductor

Claims (1)

[Claims] 1. A gas-insulated container in which a closed container is filled with an insulating gas and a main circuit conductor for energization connected in series through a circuit breaker is housed therein, and which is connected before and after the circuit breaker. In the grounding switch for switchgear, this grounding is performed by a fixed contact provided on the main circuit conductor, a movable contact that makes contact with and separates from the fixed contact, and a sliding contact between the movable contact and an insulator. A sliding contact attached to the mounting plate; a grounding lead conductor connected to the sliding contact and led out to the outside of the container in an insulated manner; A voltage detection movable conductor having a projecting tip, a voltage detection contact provided on the main circuit conductor with which the tip of the voltage detection movable conductor contacts, and a voltage detection movable conductor attached to the insulating mounting plate. Auxiliary provided at the rear end of the voltage detection movable conductor An auxiliary fixed contact with which the contact comes into contact, and a voltage detection conductor which is provided independently from the main circuit grounding circuit via the grounding lead conductor and is insulated from the outside of the container to lead out. And a main circuit voltage measuring circuit formed through the voltage detecting movable conductor is configured to be closed near a closed position of a main circuit grounding circuit formed through the movable contactor. Ground switch for switchgear.