JPH0516808Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a gas-insulated switchgear installed in electrical stations such as substations.

[Conventional technology] Gas-insulated switchgear installed in substations, etc. is constructed by housing circuit breakers, disconnectors, cable heads, lightning arresters, and other equipment in a container filled with an insulating gas such as SF ₆ gas. Configure. This gas insulated switchgear is provided with a grounding switch for grounding terminals of devices disconnected from the circuit in order to ensure work safety during inspection or repair of the device.

For example, Figures 3 and 4 show a conventionally used power receiving unit, which includes a cable head CHd, a lightning arrester LA, and a meter in a cylindrical container 1 filled with SF ₆ gas. voltage transformer PT, disconnector DS, and earthing switch ES.
It is made up of things that have been stored together. Cable head CHd, lightning arrester LA and voltage transformer PT are in container 1
These are connected to one end of the disconnector DS through main circuit conductors 2 and 3. One end of the disconnector DS is connected to another unit (for example, another power receiving unit) via the conductor 4 and an insulating spacer S1, and the other end of the disconnector DS is connected to another unit (for example, a breaker unit) via an insulating spacer S2. )It is connected to the.

The earthing switch ES consists of a fixed element 5 having a fixed contact 5a disposed inside a shield 5b, and a movable element 6 having a movable contact 6a and a shield 6b that shields a portion of the movable contact closer to the fixed contact. The contact 6a passes through the shield 6b and comes into contact with and separates from the fixed contact 5a. In this example,
A fixed element 5 was electrically and mechanically connected to the main circuit conductor 3, and a movable element 6 was bolted to insulating supports 9 and 10 fixed to frames 7 and 8, respectively, supported on the inner wall of the container 1. It is supported at one end of a rigid ground conductor 11 via a conductive bracket 12. FIG. 4 shows a support structure for the ground conductor 11 with respect to the frame 8. The three-phase ground conductor 11 is arranged on a plate-shaped insulating support fixed to the frame 8 with a predetermined inter-phase insulation distance. It is fixed to object 9 using bolts 20. The other end of the ground conductor 11 is connected to the container 1
The external terminal 14 is connected by a bolt to an external terminal 14 which is attached through an insulating bushing 13 through the bottom wall of the external terminal, and the external terminal 14 is connected to a ground potential section (earth) via an external grounding wire 15.

Also inside the container 1 is the operating shaft 16 of the earthing switch ES.
is rotatably supported by appropriate means, and one end of a drive lever 17 is fixed to this operating shaft 16. The other end of the drive lever 17 is connected to the movable contact 6
A movable shaft 1 connected to a via an insulated operating rod 18
It is pivoted to 9. The operating shaft 16 is connected to a grounding device operating device, and by rotating the drive lever 17 by rotation of the operating shaft 16, the movable contact 6a is linearly displaced and brought into contact with and away from the fixed contact 5a. ing.

In this gas insulated switchgear, the earthing switch ES
is normally closed after the disconnector DS is opened.
As a result, the terminal of the cable head CHd is grounded via the ground conductor 11, external terminal 13, and external ground wire 15. At this time, a large discharge current of the cable flows through the earthing switch ES, so the earthing switch ES is required to have short-time current carrying performance. Furthermore, the ground conductor 11 needs to withstand electromagnetic force due to large current. Furthermore, when performing insulation resistance tests, main circuit resistance measurements, current transformation ratio tests of current transformers (not shown), etc., the external grounding wire 15 is removed and power is applied from the external terminal 14, so the earthing switch ES The ground conductor 11 must be installed in an insulated state with respect to the container 1 as described above.

[Problems to be solved by the invention] In the conventional gas-insulated switchgear described above, the three-phase ground conductor 11 had to be placed at a predetermined interlayer insulation distance. The problem was that it required a considerable amount of space. In addition, electric field concentration tends to occur at the edges of the grounding conductor 11 and the edges of the heads of the bolts 20 that fix the grounding conductor 11, so if there is a live part 21 near these areas, an internal flash fault A will occur and the insulation will deteriorate. There was a risk of destruction.

Furthermore, if the earthing switch ES and the external terminal 13 are separated, the grounding conductor 11 becomes longer, so it is necessary to increase the number of support parts for the grounding conductor in order to withstand electromagnetic mechanical force. As the number of support parts for the ground conductor increases, there is a problem in that the number of assembly steps increases, and in some cases, it may become difficult to fix each support part in a narrow space inside the container 1. It was hot.

Furthermore, since the ground conductor 11 is a rigid body, there is a problem in that it takes a lot of time and effort to mold the ground conductor to match the structure of the mounting portion.

An object of the present invention is to provide a gas insulated switchgear that solves the above problems.

[Means for Solving the Problems] As shown in FIGS. 1 and 2 showing an embodiment of the present invention, a plurality of devices including a grounding switch are installed in a container 1 filled with an insulating gas. In a gas insulated switchgear that accommodates three phases, the grounding wire 25 led out from the earthing switch ES to the outside of the container 1 is made of a flexible conductor coated with insulation, and the earthing switch for three phases is installed. Connect the ground wires derived from container 1 to
It is characterized in that it is inserted into a metal pipe 29 fixed to.

[Operation of the invention] With the above structure, the three-phase grounding wires are all housed in the metal pipe, so the grounding wire lead-out portion can be made compact. In addition, the electromagnetic mechanical force F acting on the grounding wire can be received by the metal pipe, and almost no force is applied to the fixed part between the metal pipe and the container, so the number of fixing points for the metal pipe is small, and the grounding The work of fixing the wire lead-out portion can be simplified. Furthermore, since the metal pipe can be attached to the container without using an insulating support, the support structure for the ground wire lead-out part can be simplified. Furthermore, since the ground wire is covered with a metal pipe, the electric field around the ground wire can be relaxed, and the dielectric strength can be improved.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a power receiving unit as shown in FIG. 3, and FIG. 1 shows only the main parts related to the lead-out part of the ground wire.

The shield 6b of the 3-phase earthing switch ES is connected to the container 1.
It is supported by an insulating plate (both shown) on a metal frame fixed to the inner wall of the main body. A conductive bracket 12 is connected to the shield 6b of the earthing switch of each phase, and a connecting terminal 26 connected to one end of the core conductor of the grounding wire 25 is connected to this conductive bracket 12 with a bolt or the like. There is.

As shown in FIG. 2, the grounding wire 25 includes a flexible core conductor 27 and a flexible insulating coating 2.
The grounding wire 25 is made of a flexible conductor coated with
As shown in the figure, they are inserted all at once into a metal pipe 29.

The metal pipe 29 is formed into an L-shape as shown in FIG. 1, and mounting fittings 29a and 29b are welded to one end and the other end of the metal pipe 29, respectively. The metal pipe 29 has one end and the other end near the bracket 12 and the external terminal 1, respectively.
The mounting bracket 29a is located near the frame 30 fixed to the inner wall of the container 1.
It is fixed with bolts etc. The mounting bracket 29b is a support bracket 3 fixed to the inner surface of the container 1.
1 with bolts 32.

The other end of the ground wire 25 is led out from the other end of the metal pipe 29 to the external terminal 13 side, and a connecting terminal 33 connected to the other end of the core conductor 27 of the ground wire 25 is bolted to the external terminal 13.

In the above embodiment, the length of the metal pipe 29 is set to be long enough to cover most of the ground wire 25. The metal pipe 29 is formed to have a circular cross section, and its inner diameter is such that the three-phase ground wires 25 are arranged triangularly inside the pipe 29 as shown in FIG. The size is set so that it comes in close contact with the

As the grounding wire 25, a commercially available cable can be used as is as long as it has a predetermined current capacity. By using a commercially available cable in this way, costs can be reduced compared to the conventional case where a rigid ground conductor is used.

The configuration other than the above is similar to the example shown in FIG. 3.

When the grounding wire 25 is formed of a flexible conductor coated with insulation and inserted into the metal pipe 29 for three phases at once as described above, the bare grounding conductor is placed with an insulation distance between the phases. The grounding wire lead-out portion can be configured more compactly than in the conventional case.

Furthermore, by covering the grounding wire 25 with the metal pipe 29, the electric field around it can be alleviated, so even if there is a live part 21 such as a main circuit conductor nearby, there is no risk of internal flash shorting, and the insulation It can improve durability.

As in the above embodiment, when the three-phase grounding wire is closely inserted into the metal pipe and arranged in a triangular arrangement, the electromagnetic mechanical force F is received by the metal pipe 29, and the connection between the metal pipe 29 and the container 1 Since almost no force acts on the metal pipe 29, it is sufficient to fix the metal pipe 29 to the container 1 at two places on both ends thereof. Therefore, the work of fixing the metal pipe within the container 1 can be easily performed.

When the ground wire is made flexible as described above, there is no need for any molding process on the ground wire, and the cost of parts can be reduced and the price of the gas insulated switchgear can be lowered.

In the above embodiment, the present invention is applied to the power receiving unit, but it goes without saying that the present invention can also be applied to other units provided with a grounding switch.

[Effects of the Invention] As described above, according to the present invention, since the three-phase grounding wires are all housed in the metal pipe, the grounding wire lead-out portion can be configured compactly. In addition, the electromagnetic mechanical force acting on the ground wire can be absorbed by the metal pipe, and almost no force is applied to the part where the metal pipe and the container are fixed, so the number of places where the metal pipe is fixed can be reduced and the ground wire This has the advantage that the work of fixing the drawer part can be simplified. Furthermore, since the metal pipe can be attached to the container without using an insulating support, the support structure for the grounding wire lead-out part can be simplified, and the number of places to fix the metal pipe can be reduced. It is possible to reduce the number of steps required to assemble the gas insulated switchgear. Furthermore, since the ground wire is made flexible, it is possible to omit any molding process for the ground wire, thereby reducing the number of assembly steps and the manufacturing cost of the device. Furthermore, since the ground wire is covered with a metal pipe, the electric field around the ground wire can be relaxed, and the dielectric strength can be improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing the main parts of an embodiment of the present invention;
Figure 2 is an enlarged sectional view of the main part of the embodiment shown in Figure 1;
The figure is a configuration diagram showing a conventional example, and FIG. 4 is an enlarged sectional view of the main part of FIG. 3. 1... Container, 5... Fixed element of earthing switch, 6... Movable element of earthing switch, 25...
...Grounding wire, 29...Metal pipe, ES...Earthing switch.

Claims (1)

[Claims for Utility Model Registration] In a gas-insulated switchgear in which a plurality of devices including an earthing switch are housed for three phases in a container filled with insulating gas, the gas-insulated switchgear is led out from the earthing switch to the outside of the container. The grounding wire is composed of a flexible conductor coated with insulation, and the grounding wires led out from the grounding switches for three phases are inserted into a metal pipe fixed to the container. gas insulated switchgear.