JPH02101908A - Compressed gas insulation switchgear - Google Patents

Abstract

PURPOSE:To improve insulating reliability of a magnetic ring and to absorb surge voltage effectively by blunting the wave front of surge voltage which breaks into a magnetic ring material in taking advantage of branch sections and curved contact sections. CONSTITUTION:A high voltage conductor 11 is kept insulated in an earth metal container 1 filled with compressed insulating gas, at two branch sections 14a and 14b of which the conductor 11 is connected to the 2nd and 3rd high voltage conductors 21a and 21b orthogonally arranged to the conductor 11. Between branch sections 14a and 14b a magnetic ring 13 is provided so as to surround the high voltage conductor 11. When the high frequency surge generated between the poles of a breaker and a disconnector gate to the brunch section 14a or 14b, the propagation mode is changed and the wave front becomes low. As a result, the high frequency surge getting to the magnetic ring 13 is so small in crest value that the design of the magnetic ring 13 will be easy and its reliability improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to gas insulated equipment, and in particular to a device that can effectively suppress high frequency surges that occur when operating a switchgear. The present invention relates to a gas insulated switchgear.

(Prior Art) Gas-insulated switchgear has been widely used in recent years as a switchgear for high-voltage circuits used in substations, switchyards, and the like.

This gas-insulated switchgear houses busbars, circuit breakers, disconnectors, and other R equipment in a grounded metal container. , an insulating gas such as SF6 gas, which is odorless, harmless, and has a dielectric strength 2 to 3 times that of air, is sealed to insulate equipment and used as a switchgear for high voltage circuits.

It is a well-known fact that in such gas-insulated switchgear, high-frequency surges are generated within the device when a disconnector or circuit breaker is operated. Especially when operating a disconnect switch, the rising part of the wave crest is 3 to 5 ns, and the maximum peak value of the following high frequency vibration of several MH2 is 2 ns of the constant operating voltage.
A surge voltage that is more than twice as high (2° Opu or more) can occur. In this case, the equipment in the gas-insulated switchgear generally has a coaxial structure, and the surge generated inside propagates with almost no attenuation, so there is a high risk of insulation breakdown or ground fault caused by this high-frequency surge. . Specifically, we have seen cases where dielectric breakdown occurred in oil bushings due to the steep wave crest of surges, and cases where arcs between the poles of disconnectors caused by the surge peaks caused grounding to a grounded metal container. There have been reports of accidents involving cars. Furthermore, these surges are induced into the grounding system of the gas-insulated switchgear, causing various propagation problems and destruction of the low-voltage control circuit. Therefore, it is necessary to suppress the high frequency surge generated within the gas insulated switchgear by some means.

Here, as a method for suppressing high frequency surges generated when operating a disconnector, there is a method disclosed in, for example, Japanese Patent Laid-Open No. 61-227325. This is shown in FIG.

That is, FIG. 9 is a sectional view of the disconnector 7 of the gas insulated switchgear. In the figure, 1 is a grounded metal container, and 2 is this grounded metal container 1.
In the grounded metal container 1, first and second fixed electrodes 4a and 4b are disposed close to each other with their axes aligned and are supported by the insulating spacer 2. has been done. First and second fixed electrodes 4a.

4b is hollow, and contacts 5a and 5b are provided on the inner peripheral surface. A movable electrode 6 is provided inside the second fixed electrode 4b, the outer peripheral surface of which is in contact with the contactor 5b, and which is slidable in the axial direction of the fixed electrode 4b. A contact 8 is provided. Further, an operating mechanism 10 is provided outside the grounded metal container 1, and the operating force of this operating mechanism 10 is transmitted to the movable electrode 6 via the operating rod 9, moving the movable electrode 6 in the direction of the first fixed electrode 4a. The movable electrode 6 can be moved forward and backward.
and the first fixed electrode 4a can be brought into contact with and separated from each other. Roughly speaking, the first and second fixed electrodes 4a and 4b are connected to a high voltage conductor 11 housed in an adjacent grounded metal container 1 via a connection electrode 12 fixed at the center of the insulating spacer 2. There is. And, on the left and right between the disconnector poles, there are first,
so as to surround the second fixed electrodes 4a and 4b, respectively.
A cylindrical structure made of a magnetic material (hereinafter referred to as a magnetic material ring) is installed, and the large inductance component of the magnetic material absorbs the surge generated in the disconnector, and the surge propagates to the outside of the disconnector. This can be prevented.

(Problem to be Solved by the Invention) By the way, in the conventional example shown in FIG. 9, the step-shaped traveling wave generated at the disconnector contact propagates in both directions of the contact and first enters the magnetic rings 13a and 13b. do. Therefore, the magnetic material ring 13a.

The surge that enters 13b maintains its initial waveform and contains extremely high frequency components.

Due to the large inductance component caused by the magnetic material, this part becomes an open end for high frequency components, and a voltage twice as high as that of the traveling wave is generated. Further, correspondingly, a large one-turn voltage is generated also in the circumferential direction of the cross section of the magnetic material rings 13a, 13b. This one-turn voltage becomes larger as the frequency becomes higher. In particular, the step-like traveling wave generated between the poles of the disconnector enters the magnetic rings 13a and 13b while maintaining its steepness.
A large one-turn voltage is applied to a and 13b, and furthermore,
The higher the frequency, the more magnetic material ring 13a.

Since the voltage range applied to 13b is localized and a large voltage is applied to a small area, insulation design becomes difficult and reliability decreases.

Furthermore, because the axial length of the disconnector cannot be made that long due to the arrangement, the magnetic rings 13a, 1
Since the length of the magnetic material rings 3b cannot be very long, the magnetic material rings 13a and 13b must be made thicker in the radial direction in order to obtain a sufficient surge suppressing effect. In this case, a large voltage will be generated in the radial direction, and the direction of this electric field will be the same as the direction of the electric field that the high voltage electrodes 4a and 4b form with respect to the grounded metal container 1, further reducing reliability. It ends up.

In addition to disconnectors, in general various switching devices such as circuit breakers, suppression of high-frequency surges that occur during switching operations is an issue.

The present invention was proposed in order to solve the problems of the prior art as described above, and its purpose is to effectively suppress high frequency surges that occur when operating a switchgear, etc.
Moreover, it is an object of the present invention to provide a highly reliable gas insulated switchgear.

[Structure of the Invention] (Means for Solving the Problems) First, the invention as set forth in claim 1 provides a high voltage conductor with:
It is characterized in that two or more branch portions are provided and a magnetic ring is placed so as to surround the high voltage conductor between the branch portions.

In addition, the invention according to claim 2 connects the high voltage conductor to the contact point of the disconnector, and between the high voltage conductor and the contact point of the disconnector,
It is characterized in that it is installed so as to have at least one bent part of approximately 90'', and a magnetic material ring is installed so as to surround this high voltage conductor.

(Function) First, in the gas-insulated switchgear described in item 1, a surge that enters the magnetic ring will always be branched out, no matter what circuit configuration or what kind of switchgear is operated. pass through the section. It is easy to understand that the surge is dispersed and the peak value becomes lower when passing through the branch, but in addition to this, it was confirmed that the steepness of the surge was reduced.

Therefore, in the present invention, the magnetic material ring can be easily insulated and reliability can be improved.

In addition, in the gas-insulated switchgear described in item 2, the surge that enters the magnetic ring cannot propagate to the magnetic ring without changing the direction in a straight line from the contact point of the disconnector, and the propagation direction is approximately After undergoing at least one direction change of 90', the magnetic material enters the ring. It was confirmed that when this propagation direction is changed, the propagation mode changes, which blunts the surge wavefront and attenuates high-frequency components. For this reason, the surge waveform that enters the magnetic material ring has a blunt wavefront that does not include high frequency components. Therefore, according to the present invention, it is possible to easily insulate the magnetic material and provide a highly reliable gas insulated switchgear.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings. Note that the same parts as those in the prior art shown in FIG. 9 are denoted by the same reference numerals, and explanations thereof will be omitted.

■Embodiment to which the invention described in item 1 is applied FIG. 1 is a front cross-sectional view of a part of the bus bar of a gas-insulated switchgear showing an embodiment of the present invention, and FIG. 2 shows a magnetic material according to the present invention. It is a single line diagram of a general substation showing the installation location of the ring.

In FIG. 1, a grounded metal container 1 filled with an insulating gas 3
A high-voltage conductor 11 is installed in an insulated manner, and 2
The branch portions 14a and 14b are connected to second and third high voltage conductors 21a and 21b arranged in orthogonal directions. No separable contacts are installed between the two branch portions 14a and 14b, and a magnetic ring 13 is installed in this portion so as to surround the high voltage conductor 11. Here, the magnetic material ring 13 has, for example, a structure in which an amorphous alloy film is wound together with an insulating film many times, or a structure in which amorphous alloy powder is hardened with an insulating resin such as an epoxy resin. Note that the second and third high voltage conductors 21a and 21b are connected to openable/closeable contacts such as a disconnector or a circuit breaker, which are not shown in FIG.

Moreover, the magnetic material ring 13 shown in FIG. 1 corresponds to the first magnetic material ring 13 in FIG.
In the figure, 16 represents a circuit breaker, and 17 represents a first disconnector. In FIG. 2, a second magnetic material ring 13a is also provided to surround the high voltage conductor of the bus connecting the bushing or cable head 18 and the second disconnector 17a. In addition, 15 in Figure 2
indicates a transformer.

The operation of this embodiment having the above configuration is as follows.

That is, the high frequency surge generated between the poles of the circuit breaker 16 or the first disconnector 17 in FIG. 2 is transmitted to the second high voltage conductor 21a or the third high voltage conductor 31 in FIG.
b, and reaches the branch portion 14a or 14b.

Here, the high frequency surge is dispersed and propagated in both directions of the high voltage conductor 11, and at the same time
, the propagation mode changes and its steepness decreases.

As a result, the high frequency surge that reaches the first magnetic material ring 13 becomes a surge with a blunt wave crest and a small wave height value. Therefore, the insulation design of the magnetic material ring 13, which has been difficult in the past, becomes easy and reliability is improved.

In addition, in FIG. 2, when all the circuit breakers 16 and the first circuit breaker 17 except the second circuit breaker 17a are operated, the high frequency surge is always directed to the installation part of the first magnetic material ring 13. and is absorbed by this magnetic material ring 13. Moreover, the high frequency surge generated when the second disconnector 17a is operated does not enter the first magnetic material ring 13, but is absorbed by the second magnetic material ring 13a.

By the way, in order to maintain the clearance between the busbars having the high voltage conductors 21a and 21b, the distance between the branch parts 14a and 14b is set long, so the first magnetic material ring 13 in this embodiment extends over a long distance. Therefore, the thickness of the magnetic material ring 13 in the radial direction can be reduced accordingly. Therefore, 1 of the first magnetic material ring 13
The radial component of the turn voltage becomes smaller and the high voltage conductor 1
The insulation reliability for the grounded metal container of No. 1 is also improved.

Moreover, if the thickness of the first magnetic material ring 13 can be reduced, the change in characteristic impedance at the installation location of the magnetic material ring 13 can be reduced, so that high frequency surges can be reduced in the first magnetic material ring 13. It becomes easier to pass through the installation part, and steep wave surges can be effectively absorbed by the eddy current loss of the first magnetic material ring 13.

Furthermore, since the surge generated when all the circuit breakers 16 and the second disconnector 17 except the second disconnector 17a are operated always enters the first magnetic material ring 13, a small amount of magnetic material is effective. Surges can be effectively suppressed.

On the other hand, the busbar connecting the bushing or cable head 18 and the disconnector 17a is elongated within the membrane and has a simple structure. From this, the thickness of the second magnetic ring 13a installed in this area can be made as small as the first magnetic ring 13, so even if the steepness of the surge wavefront does not decrease, the insulation design can be improved. This is easy, and it is easy to further strengthen the insulation compared to the first magnetic material ring 13. Therefore, with this magnetic material ring 13a,
The steep wave surge associated with the operation of the second disconnector 17a can be effectively reduced without reducing reliability.

Further, the steep wave surge generated in this portion propagates to an overhead line or cable (not shown) and is diffused, so a large-scale surge absorption device is not required.

Note that the present invention is not limited to the above-mentioned embodiment, and for example, as shown in FIG.
Similar effects can be obtained when applied to a device in which the insulating spacer 2 is installed at the insulating spacer 14b.

Further, as shown in FIG. 4, a branch portion 14C including the high voltage conductor 21G at the end of the high voltage conductor 11 can also be regarded as a similar branch portion. In this case, although the wave height of the steep wave surge entering the magnetic material ring 13 does not decrease, the branching portion 14
The wave crest is blunted due to the capacitance that the high voltage conductor 21G at the end connected to c has with respect to the grounded metal container 1, and due to the combination of this blunting and the wave crest blunting due to the branch portion 14C, the wave crest of the surge becomes more prominently blunted. shows. Therefore, even in the configuration shown in FIG. 4, the absolute radius design of the magnetic material ring 13 remains easy.

By the way, in each of the above embodiments, a single-phase bus has been illustrated and explained, but the present invention is a three-phase bus in which three high voltage conductors are housed in one grounded metal container. Exactly the same effect can be obtained on the bus bar by installing the magnetic ring 13 so as to surround the high voltage conductor 11 of each phase. In addition, in the case of a three-phase bundled bus, as shown in FIG. A similar effect can be obtained even when the configuration is configured to do this. In addition, 19 in FIG. 5 is 7 lunges which connect between the grounded metal containers 1.

Roughly speaking, in FIG. 2, the magnetic material ring 13 is installed at all installation locations where the effect of the magnetic material ring 13 according to the present invention can be obtained.
3, 13a@ installed, but partially magnetic material ring 1
Just by installing 3.138, you can obtain steep wave surge reduction effect.

(2) Embodiment to which the invention described in item 2 is applied FIG. 6 is a front sectional view of a gas insulated switchgear showing an embodiment of the present invention.

In FIG. 6, the grounded metal container 1 of the disconnector 7 and the grounded metal container 1 of the bus bar are arranged in a 1-shape and connected. An axial end of the grounded metal container 1 of the disconnector 7 is covered by a cover 1a, and an operating mechanism 10 is disposed in the lid of the cover 1a. Second fixed electrode 4 of disconnector 7
b is insulated and held by the cover 1a via the insulating cylinder 22,
Fixed. On the side surface of this second fixed electrode 4b,
A connection electrode 23 is fixed, and this connection electrode 23 is connected to the container 1.
It is connected to the high voltage conductor 11 of the bus bar through a connecting electrode 12 fixed at the center of an insulating spacer 2 fixed therebetween. That is, there is no contact point of the disconnector in the axial direction of the high voltage conductor 11, and the axial direction of the contact point between the high voltage conductor 11 and the disconnector 7 forms an angle of 90'. A magnetic ring 13 is installed to surround the high voltage conductor 11.

In this embodiment having the above configuration, the disconnector 7
When the surge generated at the contact point propagates from the base end of the second fixed electrode 4b to the connection electrode 23, it travels approximately 90 degrees in the traveling direction.
0' transition, after which it penetrates the magnetic material ring 13 arranged around the high voltage conductor 11. When the surge changes its traveling direction by approximately 90' in this way, the propagation mode changes and the wave front becomes blunt. The reason for this is as follows. In other words, at an approximately 90° bend, the electromagnetic waves traveling inside the bend are 90°.
While the propagation distance required to make a 0' bend is short, electromagnetic waves traveling on the outside require a long propagation distance to make a 90' bend. Therefore, time is generated in the internal and external electromagnetic waves, which slows down the wave front of the surge. In this way, the waveform of the surge that enters the magnetic material ring 13 has a blunt wave crest.
In addition, the waveform does not contain very high frequency components, so
Insulation of the magnetic material ring 13 becomes easy. As a result, there is no risk of dielectric breakdown occurring in the magnetic material ring 13 portion. Therefore, surges can be reliably suppressed, and at the same time, local dielectric breakdown of the magnetic material ring 13 does not occur, so there is no fear of a ground fault to the grounded metal container 1. In this way, this embodiment can provide a highly reliable gas insulated switchgear.

Furthermore, the present invention is not limited to the above-mentioned embodiments. For example, as shown in FIG. In addition, if the magnetic rings 13 are placed on both sides of the branch 14 of the high voltage conductor 11, the branch 14 functions approximately the same as the 90' bent portion, and the same effect can be obtained.

Furthermore, when a second disconnector 7a is arranged via a circuit breaker 16 as shown in FIG. 8 in the axial direction of the high voltage conductor 11 opposite to the branch part 14 in FIG. Since the high voltage conductor 11 and the second disconnector 7a are separated, it can be considered that the contacts of the disconnector 7 are not connected in the axial direction of the high voltage conductor 11, and the same effect can be obtained. 8th
In the illustrated embodiment, when the second disconnector 7a is actually operated, the circuit breaker 16 is always in the open state, so the surge generated at the contact of the second disconnector 7a is transferred to the magnetic ring 13. It will not invade the installation location. In addition, wire-wound current transformers are generally installed on both sides of the circuit breaker 16, and these wire-wound current transformers also have a magnetic material. Since it is for measurement, it is not related to surge suppression of the present invention.

[Effects of the Invention] As explained above, in the present invention, the surge voltage that enters the magnetic material ring can be blunted by using the branching part or the bending part, and the peak value can be reduced. The insulation reliability of the ring can be improved, and surge voltage can be effectively absorbed by the magnetic ring. Therefore, it is possible to provide a highly reliable gas-insulated switchgear that can effectively suppress high-frequency surges that occur during operation of the switchgear.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing a part of the busbar of a gas insulated switchgear according to an embodiment of the invention described in item 1, and FIG.
FIGS. 3 to 5, which are single line diagrams of a general substation showing the installation locations of magnetic material rings according to the embodiment shown in the figure, are diagrams of a gas insulated switchgear according to an embodiment that also contributes to the invention described in item 1. It is a front sectional view showing a part of a generatrix. Figure 6 is the second
FIGS. 7 and 8 are front sectional views showing the vicinity of the disconnector of a gas insulated switchgear according to an embodiment of the invention described in Section 2, and FIGS. 9 is a front sectional view showing a disconnector of a conventional gas insulated switchgear. DESCRIPTION OF SYMBOLS 1... Grounded metal container, 1a... Cover, 2... Insulating spacer, 3... Insulating gas, 4a, 4b... Fixed electrode. 5a, 5b... Contactor, 6... Movable electrode, 7, 7a
. 17.17a... Disconnector, 8... Arc contact, 9... Operating rod, 10... Operating mechanism, 11, 11a
, 11 b, 21a, 21 b, 21G--High voltage conductor, 12.23-- Connection electrode, 13, 13a, 13b
-... Magnetic material ring, 14.14a to 14G... Branch, 15... Transformer, 16... Circuit breaker, 18...
Bushing or cable head, 19...7 langes, 22...insulation tube. 1 11m 112 Figure

Claims (2)

[Claims] (1) In a gas insulated switchgear in which a high voltage conductor is arranged in a grounded metal container filled with an insulating gas, the high voltage conductor is provided with two or more branch portions, and a branch portion between the branch portions is provided. A gas insulated switchgear characterized in that a magnetic ring is installed to surround a high voltage conductor. (2) In a gas-insulated switchgear comprising a high-voltage conductor disposed within a grounded metal container filled with insulating gas, the high-voltage conductor is connected to a contact of a disconnector, and between this contact, A gas insulated switchgear characterized in that the high voltage conductor is installed so as to have at least one bent portion of approximately 90 degrees, and a magnetic material ring is installed to surround the high voltage conductor.