JP6081065B2 - Gas insulation equipment - Google Patents

Description

  The present invention relates to a gas insulating device using an insulating material whose dielectric constant changes nonlinearly with electric field strength.

  At present, gas insulation equipment in which an insulating gas is sealed in a metal container is widely used in power systems. Here, the structural example of a general gas insulation apparatus is concretely demonstrated using FIG. As shown in FIG. 10, the insulating gas 4 is sealed in the metal container 2, and the energizing high voltage conductor 1 insulated and supported by the support insulating portion 3 is inserted.

As the insulating gas 4 sealed in the metal container 2, SF ₆ gas excellent in insulating performance and cooling performance is used. Such gas insulation equipment has gained high demand and is now the mainstream of gas insulation equipment in substations and power plants. Furthermore, in recent years, application to a 1100 kV class system is also planned, and higher voltage and higher capacity tend to be further promoted.

  By the way, when the voltage of the gas insulated device is increased, the electric field strength of the high voltage conductor 1 is increased. Therefore, in order to obtain excellent insulation performance, the device is enlarged and the insulation distance between the high voltage conductor 1 and the metal container 2 is increased. Or the pressure of the insulating gas 4 to be sealed needs to be increased. When the pressure of the insulating gas 4 is increased, the metal container 2 must be a pressure container that can withstand the pressure. However, it is very difficult to manufacture such a metal container 2 in the current manufacturing process. Therefore, in order to ensure excellent insulation performance when the voltage of the gas insulation device is increased, it is necessary to increase the size of the device.

  Substations using such large-sized gas insulation equipment form the basis of power supply, but recently there has been a strong demand for application to urban substations and improvement in economic efficiency, so the size of the equipment can be reduced. There is an urgent need to plan.

Furthermore, SF ₆ gas, which is widely used as the main insulating gas 4, has a dielectric strength approximately three times that of air and is an indispensable substance for contributing to power supply. Insulators that contain greenhouse gases with a high global warming potential and are not regulated in Japan and overseas, or alternative gases that do not use greenhouse gases or mixed gases that reduce the use of greenhouse gases. Is considered to be applied. At present, harmless and environmentally friendly gas has lower insulation performance than SF ₆ gas, and it is difficult to increase the voltage.

  Here, the electric field distribution in the metal container of the gas insulating device will be described. Gas insulation equipment that encloses high-pressure gas typified by a gas-insulated bus has a coaxial cylindrical shape in which a high-voltage conductor is placed on the central axis of a cylindrical metal container. The closer the distance, the higher the electric field strength.

  For example, FIG. 5B shows the electric field distribution between the high voltage conductor and the metal container when the outer diameter of the high voltage conductor is 100 mm (diameter) and the inner diameter of the metal container is 400 mm (diameter). It is a graph represented by the axial direction distance from an axis | shaft. The vertical axis is normalized assuming that the average electric field (the value obtained by dividing the voltage between the high-voltage conductor and the metal container by the distance) is 1. In the case of a simple gas gap between the high voltage conductor and the metal container, the distribution is indicated by the solid line of the triangular plot, but the electric field strength increases as the voltage approaches the high voltage conductor, and doubles the average electric field on the surface of the high voltage conductor. Is over.

  In the normal insulation design, the equipment size is determined so that the insulation field can be ensured with the maximum electric field strength on the surface of the high-voltage conductor, even if an assumed overvoltage enters the high-voltage conductor, and the electric field is below the allowable electric field. . Therefore, if the maximum electric field strength on the surface of the high-voltage conductor can be reduced, the device can be made compact while ensuring the insulation performance.

As a device corresponding to the needs for the gas insulation equipment described above, a composite insulation type gas insulation equipment has been proposed. Specifically, each of the outer surface of the high voltage conductor and the inner surface of the metal container is provided with a coating of fluororesin such as PFA, FEP, PTFE, etc., and the coating thickness of the high voltage conductor fluororesin coating is 10 to 20 mm, The coating thickness of the metal container fluororesin coating is 1 to 5 mm. And there exists what provided the support insulator between these high voltage conductor fluororesin coating | covers and metal container fluororesin coating | covers (for example, refer patent document 1). In such an insulation system using a gas and an insulation coating, even when nitrogen having a low insulation power is used as the insulation gas, an insulation configuration with a size equivalent to that of a device using the current SF ₆ gas becomes possible. (For example, refer nonpatent literature 1).

Japanese Patent No. 3028975

1999 IEEJ National Convention No. 1542

  However, the gas insulation device of the composite insulation system as in Patent Document 1 has a complicated configuration in order to improve the insulation performance, and thus a simpler configuration of a high voltage conductor is required.

  The present invention has been proposed in order to solve the above-described problems, and has a simple configuration in which an insulating material is simply disposed between a metal container and a high-voltage conductor. It aims at providing the gas insulation apparatus which can implement | achieve size reduction by reducing an electric field.

The gas insulation apparatus of this embodiment has the following configuration. That is, in a gas insulating apparatus in which a high voltage conductor is inserted into a metal container in which an insulating gas is sealed and a support insulating portion for insulatingly supporting the high voltage conductor is disposed, an electric field is interposed between the metal container and the high voltage conductor. dielectric constant is arranged an insulating material varies nonlinearly with the intensity, dielectric constant of the insulating material, is greater when the normal abnormal voltage in the high voltage conductor than during operation of the gas insulated apparatus has entered.

It is an axial direction sectional view showing the composition of the gas insulation equipment concerning a 1st embodiment. It is an axial direction sectional view showing equipotential distribution (5%) when a high voltage conductor is not covered. It is an axial direction sectional view showing equipotential distribution (5%) when the high voltage conductor has an insulating coating (relative permittivity ε = 2). It is an axial direction sectional view showing equipotential distribution (5%) when the high voltage conductor has an insulating coating (relative permittivity ε = 4). (A) is sectional drawing of the radial direction of a gas insulation apparatus, (b) is a figure which shows electric field distribution. It is an axial direction sectional view showing equipotential distribution (5%) when the relative dielectric constant of the supporting insulator is uniform at ε = 6. It is an axial direction sectional view showing equipotential distribution (5%) when the relative dielectric constant of a part of the support insulator rises to ε = 30. It is an axial direction sectional view showing the composition of the gas insulation equipment concerning a 3rd embodiment. It is an axial direction sectional view showing the composition of the gas insulation equipment concerning a 4th embodiment. It is an axial sectional view showing the configuration of a conventional gas insulation device.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[First Embodiment]
(Constitution)
FIG. 1 is a configuration diagram of a gas insulating device according to the first embodiment. As shown in FIG. 1, the first embodiment is characterized in that the high-voltage conductor 1 is covered with an insulating coating portion 5. The insulating coating 5 is made of an insulating material whose dielectric constant changes nonlinearly depending on the electric field strength in the insulating coating 5. The dielectric constant of the insulating coating 5 changes when the electric field strength in the insulating coating 5 reaches a predetermined level, that is, when the threshold value is exceeded.

Further, as the insulating gas 4, SF ₆ gas having excellent dielectric strength or gas other than SF ₆ gas, that is, a single gas of nitrogen gas, dry air or carbon dioxide gas or a mixed gas containing these single gases is used. It is also possible. About another structure, it is the same as that of the structure of the general gas insulation apparatus described previously.

(Function and effect)
FIG. 2 shows the potential distribution of the gas gap between the high voltage conductor 1 and the metal container 2 when the high voltage conductor 1 is not covered with the insulating coating 5. L in the figure indicates a central axis common to the high voltage conductor 1 and the metal container 2. From FIG. 2, it can be seen that the potential distribution interval becomes narrower and the electric field strength increases as the metal container 2 approaches the high voltage conductor 1 arranged at the center.

  FIG. 3 shows a potential distribution when the high voltage conductor 1 is coated with the insulating coating 5 and shows a case where the dielectric constant of the insulating coating 5 is ε = 2. In this case, the potential sharing of the gas gap between the insulating coating 5 having a low relative dielectric constant and the metal container 2 is increased, and the electric field strength on the surface of the high voltage conductor 1 is reduced.

  Further, FIG. 4 shows a potential distribution when the dielectric constant of the insulating coating 5 is ε = 4. Compared with the case where the dielectric constant of the insulating coating 5 shown in FIG. 3 is ε = 2, the electric field strength on the surface of the high voltage conductor 1 is further reduced. Thus, as the relative dielectric constant of the insulating coating portion 5 increases, the potential burden of the gas gap between the insulating coating portion 5 and the metal container 2 increases, and the electric field strength on the surface of the high voltage conductor 1 is reduced.

  The dielectric constant and electric field distribution characteristics of the insulating coating 5 will be described in detail with reference to FIG. Fig.5 (a) is sectional drawing of the radial direction of a gas insulation apparatus. Z in the figure indicates the position of the axial center of the high-voltage conductor 1. A indicates the surface of the high-voltage conductor 1, B indicates the surface of the insulating coating 5, and C indicates the inner surface of the metal container 2. FIG.5 (b) is a graph which shows the electrolysis distribution in a gas insulation apparatus. In FIG. 5B, the outer diameter of the high voltage conductor portion 1 is 100 mm (diameter), the outer diameter of the insulating material coating portion 5 is 200 mm (diameter), and the inner diameter of the metal container 2 is 400 mm (diameter). 4 is a graph showing the electric field distribution in the metal container 2 with the horizontal axis representing the distance from the central axis Z in the radial direction. The vertical axis is normalized assuming that the average electric field (the value obtained by dividing the voltage between the high-voltage conductor and the metal container by the distance) is 1.

  In FIG. 5B, the square plot shows the case where the relative dielectric constant of the insulating coating 5 is ε = 2, and the round plot shows the case where the relative dielectric constant of the insulating coating 5 is ε = 4. On the surface A of the high voltage conductor 1, the larger the relative dielectric constant of the insulating coating 5, the greater the potential burden on the gas gap between the insulating coating 5 and the metal container 2, and the lower the electric field on the surface of the high voltage conductor 1. ing. On the other hand, on the inner surface C of the metal container 2, since the potential burden of the gas gap increases, the electric field strength increases as the relative dielectric constant of the insulating coating 5 increases.

  Here, the gas insulating device needs to suppress the electric field on the surface of the metal container 2 in order to suppress the behavior of the metal foreign matter retained on the surface of the metal container 2 at a normal operation voltage (AC voltage). On the other hand, when an overvoltage such as an impulse voltage caused by lightning enters the high-voltage conductor 1, it is a phenomenon with a very short duration. Therefore, it is better to suppress the electric field on the surface of the high-voltage conductor 1 that tends to be a discharge start than a metal foreign object. desirable.

  For this reason, the operating voltage by the normal AC voltage suppresses the relative dielectric constant of the insulating coating part 5, and the electric field strength in the insulating coating part 5 changes the dielectric constant of the insulating coating part 5 when an abnormal voltage enters due to lightning or the like. The relative dielectric constant of the insulating coating 5 is increased beyond a threshold value that is a boundary. For example, with respect to the electric field in the insulating coating portion 5, the relative dielectric constant is suppressed to ε = 2 by the electric field strength during normal operation, and the relative dielectric constant is increased to ε = 4 at the time of abnormal voltage intrusion. As shown in FIG. 5 (b), the electric field strength on the inner surface of the metal container 2 is lowered during normal operation (ε = 2), and the electric field strength on the surface of the high-voltage conductor 1 even during abnormal voltage entry (ε = 4). Can be less than or equal to the average electric field.

The first embodiment having the above-described configuration can reduce the maximum electric field strength on the surface of the high-voltage conductor 1 while having a simple configuration in which the surface of the high-voltage conductor 1 is covered with the insulating coating portion 5. . Therefore, the insulation distance between the high voltage conductor 1 and the metal container 2 can be shortened, that is, the equipment size can be reduced. Further, since the maximum electric field strength on the surface of the high-voltage conductor 1 is reduced, a gas having a lower insulation performance than SF ₆ can be used without changing the size of the device, which can contribute to a reduction in environmental load. .

[Second Embodiment]
(Constitution)
FIG. 7 shows an equipotential distribution (5%) of the gas insulating apparatus according to the second embodiment. This embodiment is characterized in that the support insulator 3 is made of an insulating material whose dielectric constant changes nonlinearly depending on the electric field strength. About another structure, it is the same as that of 1st Embodiment. The dielectric constant of the support insulator 3 changes when the electric field strength in the support insulator 3 reaches a predetermined level, that is, when the threshold value is exceeded.

(Function and effect)
FIG. 6 shows a case where the relative dielectric constant of the support insulator 3 is constant at ε = 6 and does not change. As shown in FIG. 6, the electric field strength on the surface of the high voltage conductor 1 is the highest. On the other hand, FIG. 7 shows a case where an insulating material that changes nonlinearly with the electric field strength is used for the supporting insulator 3. Specifically, the relative dielectric constant ε = 6 when the electric field strength in the support insulator 3 is smaller than a threshold value that is a boundary where the dielectric constant changes, and when the electric field strength exceeds the threshold value, the relative dielectric constant is ε = 30. Insulating material was used.

  With such a configuration, as shown in FIG. 7, the dielectric constant changes between the high voltage conductor 1 side of the support insulator 3 and the metal container 2 side at the D line as shown in FIG. 7, and the high voltage conductor 1 side of the support insulator 3. Has a relative dielectric constant ε = 30, and the dielectric constant ε = 6 on the metal container 2 side. As a result, the potential burden on the metal container 2 side of the support insulator 3 is increased, so that the electric field strength in the connection portion between the support insulator 3 and the high voltage conductor 1 and in the vicinity thereof is reduced.

The second embodiment having such a configuration reduces the maximum electric field strength on the surface of the high-voltage conductor 1 while being a simple method of configuring the support insulator 3 with an insulating material whose dielectric constant changes depending on the electric field strength. can do. Therefore, the support insulator 3 can be reduced in size, that is, the equipment size can be reduced. Further, since the maximum electric field strength on the surface of the high-voltage conductor 1 is reduced, a gas having a lower insulation performance than SF ₆ can be used without changing the size of the device, which can contribute to a reduction in environmental load. .
[Third Embodiment]

(Constitution)
FIG. 8 is a configuration diagram illustrating a gas insulating device according to the third embodiment. The present embodiment is characterized in that a barrier insulator 6 made of an insulating material whose dielectric constant changes depending on the electric field strength is interposed between the high voltage conductor 1 and the metal container 2. The barrier insulator 6 is a cylindrical member coaxial with the high voltage conductor 1 and the metal container 2. About another structure, it is the same as that of 1st Embodiment.

(Function and effect)
In the third embodiment having such a configuration, in addition to the effects of the first embodiment, the arrangement and shape of the barrier insulator 6 can be changed. Therefore, the arrangement, shape, and electric field are combined. The electric field distribution in the metal container 2 can be controlled by changing the dielectric constant by controlling the electric field.
[Fourth Embodiment]

(Constitution)
FIG. 9 is a configuration diagram illustrating a gas insulating device according to the fourth embodiment. In the fourth embodiment, the present invention is applied to a gas insulating device having a current interrupting capability, and a fixed contact portion 7 and a movable contact portion 8 are arranged oppositely and accommodated in the metal container 2. In this embodiment, the outer peripheral surfaces of both the contact portions 7 and 8 are covered with the insulating coating portion 5 whose dielectric constant changes depending on the electric field strength.

The fourth embodiment having such a configuration can reduce the electric field strength of the outer peripheral surfaces of both contact portions 7 and 8 during the energization and interruption of the current, and can reduce the equipment size. it can. Further, as in the first embodiment, since the maximum electric field strength on the surface of the high voltage conductor 1 is reduced, it is possible to use a gas having a lower insulation performance than SF ₆ without changing the size of the device, and to reduce the environmental load. Can contribute to the reduction of

[Other embodiments]
In the present specification, a plurality of embodiments according to the present invention have been described. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. Specifically, a combination of all or any of the first to fourth embodiments is also included. The above embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and equivalents thereof as well as included in the scope and gist of the invention.

DESCRIPTION OF SYMBOLS 1 High voltage conductor 2 Metal container 3 Support insulation part 4 Insulation gas 5 Insulation coating part 6 Barrier insulator 7 Fixed contact part 8 Movable contact part

Claims (5)

In a gas insulating apparatus in which a high voltage conductor is inserted into a metal container in which an insulating gas is sealed, and a support insulating portion that supports the high voltage conductor is disposed.
Between the metal container and the high voltage conductor, an insulating material whose dielectric constant changes nonlinearly due to the electric field strength is disposed ,
The dielectric constant of the insulating material is greater when an abnormal voltage enters the high-voltage conductor than during normal operation of the gas-insulated equipment,
Gas insulation equipment characterized by.   2. The gas insulating apparatus according to claim 1, wherein at least a part of the high voltage conductor is covered with the insulating material whose dielectric constant changes nonlinearly according to electric field strength. That at least a portion of the insulating support portion is configured by using the insulating material having a dielectric constant is changed by the electric field strength,
The gas insulation apparatus according to claim 1 or 2, characterized by the above-mentioned. The insulating material has a dielectric constant that changes depending on a relationship between an electric field strength in the insulating material and a predetermined threshold value.
During the normal operation, the electric field strength in the insulating material is smaller than the threshold, and when an abnormal voltage enters the high-voltage conductor, the electric field strength in the insulating material is larger than the threshold.
The gas insulation apparatus according to any one of claims 1 to 3, wherein In a gas insulating apparatus in which a high voltage conductor is inserted into a metal container in which an insulating gas is sealed, and a support insulating portion that supports the high voltage conductor is disposed.
Between the metal container and the high voltage conductor, an insulating material whose dielectric constant changes nonlinearly due to the electric field strength is disposed ,
The insulating material has a dielectric constant that changes depending on a relationship between an electric field strength in the insulating material and a predetermined threshold value.
During normal operation, the electric field strength in the insulating material is smaller than the threshold, and when an abnormal voltage enters the high-voltage conductor, the electric field strength in the insulating material is larger than the threshold.
Gas insulation equipment characterized by.

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