JPH05336625A - Gas-insulated switching device - Google Patents

Abstract

PURPOSE:To obtain a gas-insulated switching device in which high-frequency surge having an abrupt rise generated upon switching of a switch such as a disconnector, etc., can be effectively suppressed. CONSTITUTION:A gas-insulated switching device has a high-voltage conductor 3 arranged in a ground metal vessel 1 in which insulation gas is sealed, and a switch electrically connected to the conductor 3. A plurality of structures each formed by alternately concentrically winding many times insulation films 13 and magnetic materials 12 and a plurality of magnetic rings 10 each formed of an insulator 14 covering the outer periphery of each structure are prepared, and they are aligned coaxially on the periphery of the conductor 3.

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 used in a substation or the like and capable of suppressing a high frequency surge generated when a switch such as a disconnector is opened and closed.

[0002]

2. Description of the Related Art In recent years, a gas-insulated switchgear has been widely used as a switchgear used in a high-voltage circuit used in a substation. This gas-insulated switchgear consists of busbars, circuit breakers,
The disconnector and other accessories are housed in a grounded metal container filled with SF ₆ gas. This SF ₆ gas is highly stable, inert, nonflammable, odorless,
Since it is harmless and has a dielectric strength 2-3 times that of air, it is often used in switchgear for high voltage circuits.

Such a switchgear generally has a coaxial structure, and a surge generated inside propagates with almost no attenuation. Further, it is a well known fact that a high-frequency surge is generated in the gas-insulated switchgear by the opening / closing operation of the disconnector and the circuit breaker. Especially when operating the disconnector
When the rising time of the wave crest is 3 ns to 5 ns, a surge voltage having a maximum peak value of a high-frequency vibration of several MHz subsequent thereto that is twice the peak value of the constant operation voltage (2 pu) or more may occur. An example of a dielectric breakdown accident of the oil bushing caused by such a steep wave front portion of the surge, or a ground fault accident from the arc between the disconnector poles to the grounded metal container due to the peak value of the surge. There have been reports of cases that caused this.

Further, these surges are induced in the grounding system of the gas-insulated switchgear, which causes various radio wave disturbances and destruction accidents of the low-voltage control circuit. Therefore, it is necessary to suppress the high frequency surge generated in the gas insulated switchgear by some means.

As a method for suppressing the high frequency surge generated during the operation of such a switchgear, Japanese Patent Application Laid-Open No. 61-66510.
There is a method disclosed in the publication. Below, about this Figure 3
Will be described. In FIG. 3, an insulating spacer 2 is attached in the grounded metal container 1.
The high voltage conductor 3 is insulated and supported by. Further, the grounded metal container 1 is hermetically sealed, and an insulating gas 4 such as SF ₆ gas is sealed inside. Further, a cylindrical structure 5 made of a magnetic material is arranged around the high-voltage conductor 3, and a shield 6 is provided so as to cover the structure 5. One end of the shield 6 and the high-voltage conductor 3 are provided. And the gap g
Are formed. The large inductance component of the structure 5 absorbs the surge and reduces the high-frequency surge generated during the opening / closing operation of the switch such as the disconnector. Further, the insulating effect of the gap g formed in the radial direction of the grounded metal container 1 prevents a current of one turn from flowing around the structure 5.

[0006]

However, the conventional gas-insulated switchgear shown in FIG. 3 has the following problems to be solved. That is, the voltage of the high-voltage conductor 3 is applied to the grounded metal container 1 in the radial direction,
When two electric fields in the same direction are simultaneously generated in the gap g portion formed at one end of the shield 6 and one turn current flows, the surge suppression effect is lost. Moreover, at the same time, there is a risk that the first developed streamer will continue to develop on the side of the grounded metal container 1 and cause a ground fault. For this reason, the gap g could not be made sufficiently large. An object of the present invention is to provide a gas-insulated switchgear capable of effectively suppressing a surge that occurs with the opening / closing operation of a switch and having high reliability.

[0007]

In order to achieve the above-mentioned object, the present invention comprises a grounded metal container in which an insulating gas is enclosed, and a conductor, and the switch is electrically connected to the conductor. In gas insulated switchgear

A plurality of magnetic rings composed of a structure in which an insulating film and a magnetic material are alternately and concentrically wound many times and an insulator covering the outer peripheral surface of the structure are prepared,
These are arranged around the conductor and in the axial direction.

[0009]

According to the present invention, since a plurality of magnetic rings are arranged side by side around the conductor, it is possible to effectively suppress a high frequency surge having a steep rise that occurs when the switch is opened and closed. It is possible to obtain a gas-insulated switchgear that is easy to handle and highly reliable.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view showing a schematic structure of a gas-insulated switchgear according to the present invention. The difference from the conventional example of FIG. 3 is that a magnetic ring 10 described below is used instead of the structure 5 and the shield 6. The point is that a plurality of them are arranged at intervals. In this case, the magnetic ring 10 is spaced from the connection conductor 7 connecting the ends of the high voltage conductors 3 by a predetermined distance.
Is provided. As shown in FIG. 2, each magnetic ring 10 has a cylindrical winding core 11 on the outer peripheral surface of the high-voltage conductor 3.
And a magnetic material 12 and an insulating film 13 are alternately wound around the outer peripheral surface of the winding core 11 a number of times, and the outer peripheral surface of the structure has an insulating material such as epoxy resin. The whole is covered with 14.

With this configuration, the following effects can be obtained, and among them, the effect of suppressing the high frequency surge exhibiting a steep rise, which is a problem in the conventional device, is great. That is, according to the present embodiment, the plurality of magnetic rings 10 are arranged at intervals with respect to the central axis direction of the high voltage conductor 3, so that one turn voltage is applied to each of the magnetic rings 10. Can be shared. Therefore,
The turn voltage per magnetic ring 10 is reduced. Further, the electric field in the radial direction of the high-voltage conductor 3 in which one turn voltage is generated becomes small, and the reliability of insulation of the high-voltage conductor 3 itself is improved.

Further, since the magnetic ring 10 is composed of a structure in which the magnetic material 12 and the insulating film 13 are alternately wound around the outer peripheral surface of the winding core 11 many times, the high voltage conductor 3 is insulated in the radial direction. Is more reliable, and insulation is maintained even if the electric field formed by the high-voltage conductor 3 and the electric field generated by one turn voltage are superposed. Further, since the outer peripheral surface of the multilayer structure formed by alternately winding the magnetic material 12 and the insulating film 13 a large number of times is covered with an insulating material 14 such as an epoxy resin, a high ratio of this insulating material 14 can be obtained. Due to the dielectric constant, it serves to electrostatically shield the magnetic ring 10.
From this, it is not necessary to add the special shield 6 required in the conventional example of FIG. 3, and the limited space can be effectively used.

Generally, for commercial frequencies of 50 Hz and 60 Hz, if the outer periphery is covered with an epoxy resin used for the insulating spacer 2 etc., it can be said that there is no problem as long as it does not affect the withstand voltage. Further, the magnetic ring 10 arranged around the high-voltage conductor 3 is used for a high-frequency surge having a sharp rise such as a disconnector surge having a frequency of several hundred KHz to several MHz or several tens of MHz. Since the rising steepness of the surge waveform becomes dull, the surge waveform whose subsequent waveform is almost determined by the rising steepness can be suppressed, and the progress to dielectric breakdown can be prevented. As described above, according to the present embodiment, the magnetic ring 10 disposed on the outer peripheral surface of the high-voltage conductor has an outer periphery made of an insulating material such as epoxy resin against a commercial frequency voltage in a steady state. Since it is covered with 14, insulation is maintained. On the other hand, with respect to a high frequency surge exhibiting a steep rise, the rise steepness of the surge waveform can be blunted, so that it can be effectively suppressed. Further, since the magnetic rings 10 each have a compact structure, they are easy to handle and their characteristics do not change even with mechanical vibration.

[0015]

According to the present invention described above, it is possible to effectively suppress a high frequency surge having a steep rise that occurs with the opening / closing operation of a switch such as a disconnector, and it is easy to handle. It is possible to provide a highly reliable gas-insulated switchgear.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a gas insulated switchgear according to the present invention.

FIG. 2 is an enlarged sectional view showing a magnetic ring portion of FIG.

FIG. 3 is a sectional view showing an example of a conventional gas-insulated switchgear.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ground metal container, 2 ... Insulating spacer, 3 ... High voltage conductor, 4 ... Insulating gas, 7 ... Connection conductor, 10 ... Magnetic ring, 11 ... Core, 12 ... Magnetic material, 13 ... Insulating film,
14 ... Insulator.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hirokuni Aoyagi 2-1, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Stock company Toshiba Hamakawasaki Plant (72) Hiroshi Murase, 2nd, Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa No. 1 Stock Company Toshiba Hamakawasaki Factory

Claims (1)

[Claims] 1. A gas-insulated switchgear in which a conductor is disposed in a grounded metal container in which an insulating gas is sealed, and a switch is electrically connected to the conductor, wherein an insulating film and a magnetic material are provided. A plurality of magnetic rings composed of an alternating concentric winding structure and an insulator covering the outer peripheral surface of the structure are prepared, and these are arranged around the conductor, and A gas-insulated switchgear characterized by being arranged side by side in the axial direction.