JPH06197427A - Gas-insulated switchgear - Google Patents

Abstract

PURPOSE:To provide a gas-insulated switchgear capable of increasing safety attended with inspection work, and capable of shortening circuit stop time required for the inspection sharply. CONSTITUTION:One electrode side of a gas circuit-breaker GCB is connected to a bushing Bg through a line-side disconnector DS1. A line-side grounding switch ES1 is connected between the bushing Bg and the line-side disconnector DS1. A grounding switch iES1 capable of causing an induction current to flow is connected between the line-side disconnector DS1 and the gas circuit-breaker GCB. The other electrode side of the gas circuit-breaker GCB is connected to a bus-bar-linking circuit connecting a first main bus-bar linking BUS1 and a second bus-bar BUS 2. A working grounding switch ES3 is connected between the gas circuit-breaker GCB and the bus-bar linking circuit. And a disconnector DS2 for a bus-bar is provided between the gas circuit-breaker GCB and the first main bus-bar BUS1, and a disconnector DS 3 for a bus-bar is provided between the gas circuit-breaker GCB and the second main bus-bar BUS1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas-insulated switchgear, and in particular, it can easily and safely carry out the work of inspecting the earthing switch on the line side and greatly reduce the downtime of substations required for the inspection. The present invention relates to a gas-insulated switchgear that is shortened and has improved checkability.

[0002]

2. Description of the Related Art In a substation or the like, an overhead line drawn from an overhead power transmission line from an adjacent power station or the like is connected to a bushing, and the overhead line from the bushing is connected to a transformer via a switchgear. . The switchgear is a device that is interposed between the bushing and the transformer in this way to open and close the electric circuit when an abnormal voltage occurs or during inspection work. There are various types of switchgear, and among them, the gas-insulated switchgear is an S switch that has an insulation capacity several times that of air.
Since F ₆ gas is used, it has an advantage that it is superior in insulation performance and arc extinction performance compared to other switchgear. Also,
The gas-insulated switchgear is completely housed in a metal container, so it is not easily affected by the external environment.
It also has the advantage that it can be miniaturized. Therefore,
Gas insulated switchgear is mostly used in recent substations and the like.

Such a gas-insulated switchgear comprises a line side circuit, a circuit breaker, a transformer side line and a main bus bar, and each line is grounded in consideration of safety. It is provided. Since this gas-insulated switchgear is an extremely important device and equipment for constructing an electric power system, it is necessary to regularly inspect it approximately every three years. During this inspection, it is not desirable to stop the entire substation for a long time, as it will have a large effect on the power supply area. Therefore, in order to minimize the downtime when conducting inspections, we are systematically implementing line-by-line and transformer-side lines. For example, when inspecting the line side line, open the circuit breaker and stop the line side line,
It is confirmed that the switching operation characteristics of circuit breakers, earthing switches, etc. are normal, and other prescribed inspections are performed.

It is desirable that the gas-insulated switchgear which needs to be inspected regularly as described above has a structure convenient for inspection. Therefore, as a gas-insulated switchgear that is convenient for equipment inspection and system operation, a double busbar type has been widely used. Here, an example of a gas insulated switchgear of a three-phase batch type and a double bus system will be described below with reference to a single wire connection diagram. That is, as shown in FIG. 5, the gas circuit breaker G
One pole side of the CB is connected to the bushing Bg via the line side disconnector DS1. And bushing Bg
Between the line side disconnecting switch DS1 and the line side grounding switch ES
1 is connected. A work ground switch ES2 is connected between the line-side disconnector DS1 and the gas circuit breaker CGB.

On the other hand, the other side of the gas circuit breaker GCB is connected to a bus connecting line connecting the first main bus BUS1 and the second main bus BUS2. A work earthing switch ES3 is connected between the gas circuit breaker GCB and the bus connecting line. Furthermore, the gas circuit breaker GCB and the first main bus B
A busbar disconnecting switch DS2 is provided between the gas circuit breaker GCB and the second main busbar BUS1, and a busbar disconnecting switch DS3 is provided between the gas circuit breaker GCB and the second main busbar BUS1.

The outline of the above gas insulated switchgear will be described below with reference to the drawings. That is, as shown in FIGS. 6 and 7, the upper outlet terminal of the container of the gas circuit breaker GCB in which the insulating gas is filled is connected via the work grounding switch ES2, the line side disconnecting switch DS1 and the line side grounding switch ES1. Connected to the bushing Bg. On the other hand, the lower outlet terminal of the container of the gas circuit breaker GCB is branched, one end is connected to the first main bus BUS1 through the busbar disconnector DS2, and the other end is connected through the busbar disconnector DS3 to the second main busbar. It is connected to the.

Further, the construction of the working earthing switches ES2 and ES3 applied to the above gas insulated switchgear will be described below. That is, as shown in FIG. 8, the rod-shaped conductor 4 is fixed in the horizontally long tank 1 in which SF ₆ gas is sealed by having both ends thereof supported by the insulating spacers 3. Further, a fixed-side contact portion 5 is provided on the upper side surface of the conductor 4. Further, a part of the upper side surface of the tank 1 is open, and one end of the tubular body 1a is connected to it. A movable side contact portion 6 is provided at a connecting portion between the tubular body 1a and the tank 1, and a lower end of a rod-shaped movable contactor 7 is inserted into the movable side contact portion 6. The upper end of the movable contact 7 is
It is rotatably connected to one end of a lever 9 via a link 8. The opposite end of the lever 9 is rotatably attached to an operating device 11 provided outside the tubular body 1a.
Then, the lever 9 is driven by the operating device 11, and the movable contact 7 is vertically moved via the lever 6 and the link 8. Therefore, when the lower end of the movable contact 7 is separated from the fixed-side contact part 6 by operating the operating device 11, the switch is open, and when the lower end of the movable contact is connected to the fixed-side contact part 6, the open / close operation is performed. The vessel is closed.

The above work earthing switches ES2, E
S3 normally has a rated short-time energization performance,
In addition to the rated short-time current-carrying performance, the line-side grounding switch ES1 is required to have induction current-carrying performance and induction current-cutting performance. That is, when an abnormal voltage is generated or a line circuit is inspected,
The gas circuit breaker GCB is opened to cut off the load current to stop the line circuit. At this time, the line side grounding switch ES1 is closed and grounded in order to perform a predetermined inspection. After the inspection, when making use of the stopped line again in the system,
Open the trackside earthing switch ES1. However, when the line-side grounding switch ES1 is closed, an electromagnetic induction current flows in the line circuit due to the load current flowing in another overhead power transmission line, so an arc is generated when the line-side grounding switch ES1 is opened. It becomes difficult to cut off. Therefore, this arc must be extinguished to interrupt the electromagnetically induced current. The degree of the induced current interruption performance is determined by the current value that must be interrupted and the recovery voltage generated between the electrodes after interruption. The electromagnetic induction current generated in this case is about 10 to 1 of the load current.
At 2%, the value is usually several 100 A to 1000 A, and the recovery voltage is several KV to several 10 KV and sometimes even 70 KV, so that the breaking performance required for the line side grounding switch ES1 is extremely high. Therefore, the contact part in the line side grounding switch ES1 has a structure in which a puffer method or a suction method in consideration of the current extinguishing performance is applied, and at the same time, the movable contact has a compression spring, compressed air, etc. The use of the structure improves the breaking performance of the line side grounding switch ES1.

FIG. 9 shows an example of a line grounding switch ES1 having a high interruption performance, which adopts the Puffer arc extinguishing system. That is, the basic structure thereof is the same as that of the work grounding switch ES2, and the lower part of the movable contact 7 is the cylindrical body 1a.
It is inserted into a cylinder 12 supported inside in a yagura shape. The inside of the cylinder 12 has a structure capable of compression filling with gas. With such a configuration, even if an arc is generated between the contact portions when the contact is opened, the gas in the cylinder 12 is compressed and the gas is blown to the contact portion, whereby the arc can be surely extinguished.

[0010]

However, the conventional example of the above gas insulated switchgear has the following drawbacks. That is, the line grounding switch ES3 for inspection
Each time the switch is opened and closed, the arc extinguishing work as described above must be performed to interrupt the induced current, so contact wear becomes faster and the life of the device cannot be extended too much.

Further, in the case of the circuit configuration as described above, when the line side grounding switch ES1 is opened with the line side disconnecting switch DS1 working grounding switch ES2 closed, an induced current causes an induced current to work working grounding switch ES2. Will flow to. The work earthing switch ES2 has no induction current energizing performance because of the above-described simple structure, and thus such a circuit structure is not preferable. To deal with this, conventionally, in order to inspect the line circuit, first, the gas circuit breaker GCB is opened to stop the line side circuit, and then the line side grounding switch ES1.
A method has been taken in which a worker climbs up to the bushing Bg and connects a ground wire to the connection terminal of the head of the bushing Bg to perform new grounding in a state in which the is closed and grounded. According to this method, even when the line side grounding switch ES1 is opened and closed, the induced current flows toward the new grounding line, and the current flowing through the work grounding switch ES1 and the like decreases, so that the line side line switch Inspection work can be performed.

However, if this method is adopted, the worker has to climb the bushing Bg before the inspection work, which is a safety problem. Further, since the work such as climbing up to the bushing Bg requires a lot of time before the inspection, there is a possibility that the down time of the line side line may be extended.

The present invention has been proposed in order to solve the problems of the prior art as described above, and its purpose is to:
It is an object of the present invention to provide a gas-insulated switchgear capable of improving safety associated with inspection work and greatly shortening the line down time required for inspection.

[0014]

In order to solve the above problems, the present invention has a circuit breaker having at least two branch outlets, and one of the branch outlets is a line side line. Connected to a bushing or a cable head via, another one of the branch outlets connected to a busbar via a transformer side line, and a disconnector and a plurality of ground switches connected to the line side line. In gas insulated switchgear,
Of the first two ground switches viewed from the bushing side or the cable head side, at least one is a ground switch having an induced current switching performance, and the other one is an induced current conduction performance or an induction current switching performance. Characterized by being a grounding switch with performance

[0015]

The operation of the present invention having the above construction is as follows. That is, at the time of inspection work, the circuit breaker is opened and the line side circuit is stopped. At this time, an electromagnetic induction current is generated in the line circuit by the load current flowing in another overhead power transmission line. Next, a grounding switch having an inductive current switching performance is opened and closed for inspection. The other grounding switch has an inductive current carrying capability, so the generated electromagnetic induction current flows through this grounding switch.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a gas insulated switchgear according to the present invention will be described below with reference to the drawings. The same members as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

(1) First Embodiment A first embodiment of the present invention will be described. The configuration of the present embodiment is basically the same as the configuration of the conventional example, except that a ground switch capable of continuously passing an induced current is used as the work ground switch on the line side. That is, as shown in the single-line connection diagram of FIG. 1, a ground switch iES1 capable of conducting an induced current is connected between the gas circuit breaker GCB and the line-side disconnector DS1. As shown in FIG. 2, the movable contactor 7 of the earthing switch iES1 is formed with a diameter and a material capable of continuously passing an induced current of several 100 A to 1000 A. Further, the fixed-side contact portion 5 and the movable-side contact portion 6 are also several 100A to 100.
It is made of a material capable of continuously conducting an induction current of 0 A, and is configured to have an induction current continuous conduction performance as a whole.

According to this embodiment, the gas circuit breaker GCB is opened for inspection, and the line side grounding switch ES1 of the line side line is opened.
When opening and closing the switch, the line side disconnector DS1 and the ground switch iE
Even if an induced current flows in the closed state with S1, this grounding switch iES1 has the ability to continuously conduct the induced current, so that the bushing Bg can be grounded sufficiently without connecting the grounding wire, so it is safe. is there. In other words, even if an induced current is generated by the load current flowing in another overhead transmission line,
Since this induced current flows in both the line on the ground switch iES1 side and the line on the line side ground switch ES1 side, the induced current flowing in the line side ground switch ES1 becomes half or less.
Further, since the line-side disconnecting switch DS1 and the grounding switch iES1 are closed and short-circuited, the line-side grounding switch ES
The inter-electrode recovery voltage after opening 1 to interrupt the induced current is almost 0V. Therefore, the contacts can be cut off instantly after the contacts are opened, and the contacts of the movable contactor 7 and the like are hardly consumed.

According to this embodiment as described above, when inspecting the line side grounding switch ES1, the line side disconnecting switch DS1 and the grounding switch iES1 may be closed.
It is not necessary to connect the ground wire to the head of the bushing Bg. Therefore, not only the dangerous work of climbing the bushing Bg to connect the ground wire is eliminated, but also the downtime of the substation required for the inspection is extremely shortened, and the flexible operation of the system operation and the equipment maintenance plan can be performed. In this example,
The grounding switch iES1 may have a structure further having an induced current switching performance.

(2) Second Embodiment A second embodiment of the present invention will be described below. That is, in the case of a normal gas-insulated switchgear, an interlock is provided to connect the line-side grounding switch ES1 and the line-side disconnector DS1 to each other in order to reduce the ground resistance. Therefore, when opening and closing the line-side grounding switch ES1 for inspection work, it is necessary to open the line-side disconnector DS1 or release the interlock once. In order to deal with this, the second embodiment, as shown in the single line connection diagram of FIG. 3, shows the bushing Bg in the first embodiment.
Between the line side disconnecting switch DS1 and the line side disconnecting switch ES
In addition to No. 1, another grounding switch iES2 having an induction current conducting performance is provided. Then, in the second embodiment, as shown in FIG. 4, the upper outlet terminal of the container of the gas circuit breaker GCB has a work grounding switch ES2, a line side disconnecting switch DS1, a line side grounding switch ES1 and a grounding switch. iE
The outer shape is connected to the bushing Bg through S2.

According to the second embodiment as described above, the grounding switch iES2 is closed at the time of inspection, so that even if an induced current is generated by a load current flowing through another overhead power transmission line, this induced current is generated. Since the current flows through both the line on the line side grounding switch ES1 side and the line on the grounding switch iES2 side, the induced current flowing in the line side grounding switch ES1 becomes half or less. Therefore, it is possible to open and close the line-side grounding switch ES1 without releasing the interlock while the line-side disconnector DS1 is closed. Further, the work earthing switch ES2 does not need to have the induction current energizing performance as in the first embodiment, and the conventional work earthing switch can sufficiently perform its function.

Therefore, not only the dangerous work of climbing the bushing Bg to connect the ground wire is eliminated, but also
The downtime of substations required for inspection will be extremely short, and flexible operation of grid operation and equipment maintenance plans will be possible. In addition,
In the present embodiment, the earthing switch iES2 may have a structure further having an induced current switching performance.

(3) Other Embodiments The present invention is not limited to the above-mentioned embodiments, but can be applied to a three-phase three-wire type gas insulated switchgear.
It can also be applied to both power transmission lines and power reception lines.

[0024]

As described above, according to the gas-insulated switchgear of the present invention, the simple structure of adding the grounding switch having the induction current energizing performance improves the safety and the inspection accompanying the inspection work. It is possible to provide a gas-insulated switchgear capable of significantly reducing the required line down time.

[Brief description of drawings]

FIG. 1 is a single wire connection diagram showing a first embodiment of a gas insulated switchgear according to the present invention.

FIG. 2 is a side sectional view showing a working earthing switch in the first embodiment of the gas-insulated switchgear of the present invention.

FIG. 3 is a single wire connection diagram showing a second embodiment of the gas insulated switchgear of the present invention.

FIG. 4 is a side sectional view showing a second embodiment of the gas insulated switchgear of the present invention.

FIG. 5 is a single wire connection diagram showing an example of a conventional gas-insulated switchgear.

FIG. 6 is a side view showing an example of a conventional gas-insulated switchgear.

7 is an enlarged side view showing the gas-insulated switchgear of FIG.

FIG. 8 is a side sectional view showing a work ground switch in a conventional gas-insulated switchgear.

FIG. 9 is a side sectional view showing a line side grounding switch in a conventional gas insulated switchgear.

[Explanation of symbols]

1 ... tank 1a ... cylindrical body 2 ... SF ₆ gas 3 ... insulating spacer 4 ... conductor 5 ... fixed contact part 6 ... movable contact part 7 ... movable contact 8 ... link 9 ... lever 10 ... main shaft 11 ... operating device 12 ... Cylinder

Claims (1)

[Claims] 1. A circuit breaker having at least two branch outlets, wherein one of the branch outlets is connected to a bushing or a cable head via a line side line, and another one of the branch outlets is connected. In the gas-insulated switchgear in which one is connected to the busbar via the transformer-side line, and the line-side line is connected to a disconnector and a plurality of grounding switches, the first viewed from the bushing side or the cable head side. At least one of the two ground switches is a ground switch having an induced current switching performance, and the other one is a ground switch having an induced current conduction performance or an induced current switching performance. Gas insulated switchgear.