JP5127607B2 - Gas insulation equipment - Google Patents

Description

  The present invention relates to a gas insulating device provided with an insulating spacer, and more particularly to a gas insulating device having improved DC withstand voltage characteristics.

  Generally, a high-voltage device is configured such that a metal current-carrying conductor to which a high voltage is applied is insulated from a ground metal container by being supported by an insulating spacer. In order to ensure the insulation reliability in this high voltage device, it is necessary to suppress the electric field applied to the insulating spacer to be equal to or lower than the electric field at which the insulating spacer causes dielectric breakdown. The electric field applied to the insulating spacer is determined from a plurality of factors such as the shape and material of the insulating spacer and the electrode arrangement around the insulating spacer, in addition to the magnitude of the applied voltage.

  In recent years, gas insulation equipment is frequently used as high voltage equipment. Insulating gas is enclosed in a sealed grounded metal container and is applied to both AC voltage transmission system and DC voltage transmission system. Therefore, when used in a DC system, as well as in an AC system, a residual DC voltage after opening / closing operation of the switchgear may be applied.

  Here, the gas insulation apparatus to which the residual DC voltage is applied will be specifically described with reference to FIGS. 9 and 10. FIG. 9 shows a state in which the disconnector 14 is adjacent to the breaker 13 in the open state, and the circuit 15 is disposed between the disconnector 14 and the breaker 13.

  Here, when the disconnector 14 is opened, a residual DC voltage 16 as shown in FIG. In the gas insulation device, the insulation gas sealed in the metal container has excellent insulation performance, so that the attenuation of the residual DC voltage 16 is small. Therefore, in the voltage insulation device, the direct current withstand voltage characteristic is important in the voltage device used in the alternating current system.

  Usually, the resistance of an object having a uniform volume resistivity is reduced by increasing the cross-sectional area. Therefore, in order to improve the withstand voltage characteristics with respect to the direct current voltage, a measure to increase the cross-sectional area of the insulating spacer is often taken. That is, by increasing the cross-sectional area of the insulating spacer, the DC withstand voltage characteristic is improved, and thereby, the DC electric field at the connecting portion between the conducting conductor and the insulating spacer is controlled.

  However, when the cross-sectional area of the insulating spacer is increased with the aim of lowering the volume resistivity, the shape of the insulating spacer naturally becomes larger, resulting in an increase in size of the gas insulating device. The demand for gas-insulated equipment is expanding due to its application to underground substations, etc., and the demand for downsizing of equipment is increasing. Therefore, the insulating spacer of the gas insulating device is required not only to improve the DC withstand voltage characteristic but also to improve the compactness.

  For example, as a technique for achieving both DC withstand voltage characteristics and downsizing, it has been studied to change the volume resistivity distribution in the insulating spacer instead of increasing the cross-sectional area of the insulating spacer. However, at present, a technique for stably adjusting the volume resistivity distribution of the insulating spacer has not been established. For this reason, it is difficult to realize an insulating spacer that achieves both compactness of the device and high performance of the DC withstand voltage characteristics by using the above technique.

Therefore, as a highly realistic technique, a technique for adjusting the potential distribution of the entire insulating spacer by applying a low-resistance agent having a low volume resistivity on the surface of the insulating spacer and changing the thickness of the low-resistance agent has been proposed. (For example, Patent Document 1). In this prior art, the resistivity distribution of the insulating spacer is changed by applying a low resistance agent.
JP 2003-23725 A (page 3 (paragraph 0017), FIG. 3)

  However, as in Patent Document 1, the following problems have been pointed out in gas-insulated equipment in which a low-resistance agent is applied to an insulating spacer. That is, the low resistance agent is generally applied to the surface of the insulating spacer by brush or spray. However, with such a coating method, uneven coating tends to occur, and it has been difficult to keep the film thickness of the low resistance agent constant.

  Therefore, a singular point of the electric field distribution is easily formed, and it was actually difficult to control the resistivity distribution as designed. Therefore, it has been a problem in providing an insulating spacer having excellent DC withstand voltage characteristics. In addition, as technical requirements for the insulating spacer, there are problems such as enhancing the corrosion resistance against the insulating gas generated by the arc and preventing the adhesion of conductive metallic foreign matter.

  By forming a film capable of discharging a residual DC voltage on the surface of the insulating spacer, the present invention makes it possible to easily and reliably control the resistivity distribution of the insulating spacer, and is excellent in DC withstand voltage characteristics and compactness, and is also insulated. An object of the present invention is to provide a highly reliable gas insulating device that has good resistance to cracked gas and hardly adheres to foreign metal particles.

In order to achieve the above object, the present invention provides a gas in which an energizing conductor to which a high voltage is applied is inserted into a grounded metal container filled with an insulating gas, and an insulating spacer for insulatingly supporting the energizing conductor is disposed. In the insulating device, a diamond-like carbon film having a conductivity characteristic in the range of resistivity 1E9 to 1E12 Ω · cm is formed on the surface of the insulating spacer.

  The diamond-like carbon film is a carbon thin film having an amorphous structure and having a diamond bond or a graphite bond. In the present invention, the diamond-like carbon film formed on the insulating spacer acts as an insulator in an energized state, but when a residual DC voltage is applied, before the insulating spacer generates local charging. Thus, a discharge body capable of discharging the residual DC voltage is obtained.

  In addition, since the diamond-like carbon film is formed by a plasma CVD method, a PVD method, or the like, it is possible to form a uniform film thickness firmly and stably as compared with application by brush or spray. Therefore, it is difficult to create a singular point of the electric field distribution, and the resistivity distribution of the insulating spacer can be easily and reliably controlled.

  In addition, since the diamond-like carbon film is excellent in corrosion resistance and plasma resistance, it becomes an excellent protective film, and the surface of the insulating spacer on which the diamond-like carbon film is formed is not eroded by the insulating decomposition gas. Furthermore, the diamond-like carbon film is not easily charged with static electricity and has a small coefficient of friction. Therefore, there is an advantage that the conductive metal foreign matter is difficult to adhere to the surface of the insulating spacer.

  According to the gas insulating apparatus of the present invention, by forming a diamond-like carbon film on the surface of the insulating spacer, when the residual DC voltage is applied, the residual DC voltage is discharged, and a partial high electric field portion is generated by local charging. The formation can be avoided, the DC withstand voltage characteristics can be enhanced while maintaining compactness, and the resistance to dielectric decomposition gas is good, and metal foreign objects are difficult to adhere, improving reliability. Can contribute.

Hereinafter, a plurality of embodiments of a gas insulation device according to the present invention will be specifically described with reference to FIGS.
(1) Representative embodiment [configuration]
As shown in FIG. 1, in this embodiment, an insulating gas 2 such as SF ₆ gas is enclosed in a ground metal container 1. An energizing conductor 3 to which a high voltage is applied is inserted in the ground metal container 1, and the energizing conductor 3 is insulated and supported by a conical insulating spacer 4 and a disc-shaped insulating spacer 6. . A structural feature of this embodiment is that a diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm is coated on both surfaces of the insulating spacers 4 and 6 in a thickness range of 10 to 100 μm. There is in point.

[Function and effect]
The operational effects of the present embodiment having the above-described configuration are as follows. That is, the diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm acts as an insulator in a normal energization state, but acts as a discharge body when a DC voltage remains in the energization conductor 3. .

  Therefore, the residual DC voltage can be discharged before the insulating spacer 4 is locally charged in the gas-insulated device to which the residual DC voltage is applied. As a result, a partial high electric field portion due to local charging is not formed, and excellent direct current withstand voltage characteristics can be obtained.

  As a method for forming such a diamond-like carbon film 5, a plasma CVD method, a PVD method, or the like is known. For example, when the diamond-like carbon film 5 is formed using a plasma assist film forming apparatus, the film quality can be precisely adjusted and the film can be formed at a low temperature.

  For this reason, the diamond-like carbon film 5 can stably form a much more uniform and homogeneous film than a coating film formed by brush or spray. Therefore, it is possible to control the resistivity distribution of the insulating spacers 4 and 6 as designed, and it is possible to prevent the insulating spacer 4 from becoming large and contribute to downsizing.

  The diamond-like carbon film 5 is excellent in corrosion resistance and plasma resistance. Therefore, it becomes a protective film for the insulating spacers 4 and 6, and the insulating spacers 4 and 6 are not eroded by the insulating decomposition gas caused by the arc generated during the operation of the switch. Therefore, it is possible to apply to the insulating spacer 4 an insulating material that is weakly eroded by the insulating decomposition gas 2 but has strong withstand voltage characteristics.

  Furthermore, the diamond-like carbon film 5 has a function of removing the charge of the insulating spacers 4 and 6, and has a very small friction coefficient of 0.05 or less. For this reason, harmful conductive metal foreign matter or the like hardly adheres to the surface of the insulating spacer 4. These points greatly improve the reliability of the insulating spacer 4 and consequently increase the reliability of the gas insulating device.

(2) Other Embodiments The present invention is not limited to the above-described embodiments, and the shape of the insulating spacer, the formation location of the diamond-like carbon film, the shape, the resistivity, the film thickness, the manufacturing method thereof, etc. It can be changed as appropriate, and specifically includes other embodiments as described below. In the other embodiments described below, the same reference numerals are given to the same components as those of the representative embodiment, and duplicate descriptions are omitted.

(2-1) Embodiment relating to formation place of diamond-like carbon film [configuration]
As shown in FIG. 2, the diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm may be formed on the entire outer surfaces of the insulating spacers 4 and 6 in a thickness range of 20 to 200 μm.

(2-2) Embodiment relating to the shape of the diamond-like carbon film [configuration]
Further, in the embodiment shown in FIG. 3, the resistivity is 1E9 to 1E12Ω as a part of the surface of the insulating spacer 4 or 6 in a fan shape from the center of the insulating spacer 4 or 6 toward the upper inner peripheral surface of the ground metal container 1. A diamond-like carbon film 5 in the cm range is formed by coating in a thickness range of 50 to 200 μm.

[Function and effect]
In the embodiment shown in FIGS. 2 and 3, the resistivity is adjusted by increasing the thickness of the diamond-like carbon film 5 without forming the diamond-like carbon film 5 on both surfaces of the insulating spacer 4 or 6. It is possible.

  Therefore, as in the above representative embodiment, it acts as an insulator in a normal energized state, and can act as a discharge body that discharges a residual DC voltage when a DC voltage remains. In these embodiments, the diamond-like carbon film 5 can be formed with a small area, and the manufacturing cost can be reduced.

(2-3) Embodiment [Configuration] Regarding Shape of Insulating Spacer
The shape of the insulating spacer can also be selected as appropriate. For example, not only a cylindrical shape or a conical shape but also a cylindrical shape, a prismatic shape, or a plate shape may be used. In the embodiment shown in FIG. 4, the current-carrying conductor 3 is suspended and supported from the upper part of the ground metal container 1 by a cylindrical insulating spacer 8 which is a so-called post type. A diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm is formed in a thickness range of 10 to 100 μm on the surface of the insulating spacer 8.

[Constitution]
In the embodiment shown in FIG. 5, the diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm is formed on the surface of only one upper leg of the tripod type insulating spacer 9 that insulates and supports the conducting conductor 3. The coating is made in the range of 100 μm.

[Function and effect]
Also in the embodiment having the insulating spacers 8 and 9 shown in FIGS. 4 and 5, the diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm acts as an insulator in a normal energized state, When the direct current voltage remains, the insulator in the gas insulation device to which the residual direct current voltage is applied acts as a discharge body that discharges the residual direct current voltage before causing local charging. Thereby, the same operation effect as the above-mentioned typical embodiment can be obtained.

(2-4) Embodiment in which diamond-like carbon film is multilayered [Configuration]
Further, a plurality of diamond-like carbon films may be stacked. For example, in the embodiment shown in FIG. 6, two diamond-like carbon films are formed. That is, a diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm is formed in a thickness range of 10 to 100 μm on the surface of the insulating spacer 4 that insulates and supports the current-carrying conductor 3. A diamond-like carbon film 10 having a resistivity higher than 1E12 Ω · cm is formed in a thickness range of 1 to 100 μm.

[Function and effect]
According to the embodiment of FIG. 6, since the diamond-like carbon film 10 having higher insulating characteristics is formed on the outermost layer on the surface of the insulating spacer 4 on which the diamond-like carbon film 5 is formed, the conductive foreign matter or the like can be used. Even when the surface of the insulating spacer 4 is somewhat fouled, the resistance value adjusted by the diamond-like carbon film 5 on the lower layer side can be maintained. Therefore, such an embodiment is suitable for a gas insulating device such as a disconnector or a circuit breaker having a high possibility of fouling.

  Further, a strong protective film can be secured by the amount of the two diamond-like carbon films 5 and 10 formed. Therefore, it is possible to apply an insulating material having an excellent withstand voltage characteristic to the insulating spacer 4 even though it is weak to the insulating decomposition gas, and the reliability of the gas insulating device is improved.

(2-5) Embodiment in which insulating spacer is applied to disconnector and circuit breaker [Configuration]
In the embodiment shown in FIG. 7, conical insulating spacers 4 are configured to be attached to both ends of a disconnector or a circuit breaker having an opening / closing part 12, and diamond-like is formed only on the opposing surfaces of the two insulating spacers 4. A carbon film 5 is formed.

[Function and effect]
In the embodiment of FIG. 7, the DC voltage may remain when the opening / closing part 12 is opened / closed. Therefore, by disposing the insulating spacer 4 formed with the diamond-like carbon film 5 in the vicinity of the opening / closing part 12, the circuit is disconnected when a plurality of opening / closing devices are connected to constitute a gas insulating device. Even so, the residual DC voltage can always be discharged by the diamond-like carbon film 5.

  In other words, no matter what combination of open / close devices are opened / closed, the voltage remaining in the cut-off circuit can be discharged by the diamond-like carbon film 5 to ensure local high electric field formation. It can be avoided. Therefore, it is possible to obtain excellent direct current withstand voltage characteristics.

(2-6) Embodiment in which diamond-like carbon films having different conductive properties are formed on the front and back of the insulating spacer [Configuration]
The embodiment shown in FIG. 8 relates to the improvement of the embodiment (2-5), and diamonds having different conductive properties are provided on the front surface and the back surface of the insulating spacer arranged on both sides of the opening / closing part 12. A like carbon film is formed.

  More specifically, a diamond-like carbon film having a resistivity in the range of 1E9 to 1E12 Ω · cm is formed on the side of the conical insulating spacer 4 and the disc-shaped insulating spacer 6 facing each other so as to sandwich the opening / closing portion 12. A diamond-like carbon film 10 having a higher resistivity than 5 is formed, and a diamond-like carbon film 5 is formed on the opposite surface. The maximum resistivity of the diamond-like carbon film 10 is about 1E16 Ω · cm. Here, the surfaces of the insulating spacers 4 and 6 facing each other so as to sandwich the opening / closing portion 12 are referred to as the back surface, and the opposite side is referred to as the front surface.

[Function and effect]
The embodiment shown in FIG. 8 has the following unique operational effects. That is, the surface of the insulating spacers 4 and 6 that does not face the opening / closing portion 12 is not affected by the conductive metallic foreign matter, and the diamond-like carbon film 5 having a resistivity in the range of 1E9 to 1E12 Ω · cm is formed on this surface. As a result, a more effective residual voltage discharge is realized.

  Further, since the conductive metal foreign matter is likely to be generated on the surface of the insulating spacers 4 and 6 facing the opening / closing portion 12, the diamond-like carbon film 10 having a resistivity higher than 1E9 to 1E12 Ω · cm is formed on this surface. As a result, the effect of reducing the influence of the conductive foreign matter can be obtained.

  According to such an embodiment, the residual voltage can be efficiently passed through the insulating spacers 4 and 6 by forming the diamond-like carbon film 5 having different conductive characteristics in accordance with the ease of generation of conductive metallic foreign matter. Can be made to be less susceptible to the influence of metallic foreign objects. As a result, it is possible to provide a gas insulation device with higher reliability.

1 is a side sectional view showing a structure of a representative embodiment of the present invention. Side surface sectional drawing which shows the structure of other embodiment of this invention. Front sectional drawing which shows the structure of other embodiment of this invention. The front sectional view at the time of applying to a post type insulating spacer in other embodiments of the present invention. The front sectional view at the time of applying to a tripod type insulating spacer in other embodiments of the present invention. Side surface sectional drawing at the time of forming two diamond-like carbon films with different conductive characteristics in another embodiment of the present invention. Side surface sectional drawing at the time of applying the insulating spacer to the switchgear in other embodiment of this invention. Side surface sectional drawing at the time of forming the diamond-like carbon film | membrane of the electroconductive characteristic which is different in the surface and back surface of an insulating spacer in other embodiment of this invention. The figure which shows the circuit which a residual DC voltage generate | occur | produces in the conventional gas insulation apparatus. The graph which shows a residual DC voltage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ground metal container 2 ... Insulating gas 3 ... Conducting conductor 4 ... Conical insulating spacer 5, 10 ... Diamond-like carbon film 6 ... Disk-like insulating spacer 8 ... Cylindrical insulating spacer 9 ... Tripod-shaped insulating spacer 12 ... Opening and closing Part 13: Open circuit breaker
14 ... Open operation disconnector 15 ... Circuit between circuit breaker and disconnector 16 ... Residual DC voltage

Claims (9)

In a gas-insulated device in which an energizing conductor to which a high voltage is applied is inserted into a grounded metal container filled with an insulating gas, and an insulating spacer that insulates and supports the energizing conductor is disposed.
A gas-insulated device, wherein a diamond-like carbon film having a conductive property in a resistivity range of 1E9 to 1E12 Ω · cm is formed on a surface of the insulating spacer. The diamond-like carbon film, the gas-insulated apparatus according to claim 1, characterized in that by adjusting the thickness and configured to have the conductive properties. The insulating spacer is a disk-shaped or conical member,
The gas insulating apparatus according to claim 1 or 2, wherein the diamond-like carbon film is formed only on one surface of the insulating spacer. The insulating spacer is a disk-shaped or conical member,
The gas insulating apparatus according to claim 1 or 2, wherein the diamond-like carbon film having different conductive characteristics is formed on one side of the insulating spacer and the other side.   2. The diamond-like carbon film is formed only on a part of the surface of the insulating spacer located between the conducting conductor and the inner wall surface of the ground metal container. The gas insulation apparatus of any one of -4.   The gas insulating device according to any one of claims 1 to 5, wherein the insulating spacer is disposed so as to suspend and support the current-carrying conductor. The insulating spacer has a plurality of legs for insulatingly supporting the conducting conductor,
The gas insulating apparatus according to any one of claims 1 to 6, wherein the diamond-like carbon film is formed only on a portion located at an upper portion of the legs of the insulating spacer. On the surface of the insulating spacer, a plurality of the diamond-like carbon films having different conductive properties are formed to be stacked,
The gas insulating device according to any one of claims 1 to 7, wherein a resistivity of the diamond-like carbon film formed on the outer side is higher than a resistivity of the diamond carbon film formed on the inner side.   The gas insulating apparatus according to claim 1, wherein the insulating spacer is applied to a disconnector and a circuit breaker.

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