JP2009284651A - Closed insulating device and method of operating the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a closed insulating device which controls the behavior of a foreign matter on the interior surface of a metal container to achieve the compactification and improved insulation reliability of the metal container. <P>SOLUTION: The closed insulating device includes a high-voltage conductor 1 which extends radially and can be divided radially into at least two portions, the metal container 3 which can be divided at least into two portions by an end flange 3a and covers the high-voltage conductor 1 across a gap that is formed between the metal container 3 and the high-voltage conductor 1 and that is filled with an insulating gas, and a spacer 4 having an insulating member 4a which is caught and fixed by the flange 3a at the outer peripheral side while supporting the high-voltage conductor 1 at the inner peripheral side. The interior surface of the metal container 3 is provided with a nonlinear resistance film 13 that is so formed as to show a high electric resistance when the intensity of an electric field acting on the interior surface of the metal container 3 is a given value or less and show a low electric resistance when the intensity is higher than the given value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hermetic insulation device such as a gas-filled switch and an operation method thereof.

  In a sealed insulation device such as a gas-filled switch in which a high-voltage conductor supported by an insulator is sealed inside a container filled with an insulating gas, the insulation design can be streamlined to reduce costs and environmental impact. Further reduction by three-phase integration is an issue.

  The size of the metal container of the hermetic insulation device is determined by insulation and thermal design. One of the points of insulation design is to examine the degree of influence on the insulation performance when foreign matter is present (attached) on the inner surface of the metal container.

  If foreign matter exists inside the sealed metal container that supports the high-voltage conductor with an insulator and encapsulates the insulating gas, the force generated by the interaction between the operating voltage and the charge supplied from the metal container to the foreign substance Foreign objects may move around inside the metal container.

  When the sealed insulating device is reduced in size, the electric field on the inner surface of the metal container is increased, and the movement of foreign substances existing inside the metal container tends to be active. If the foreign object moves excessively inside the metal container, it may affect the insulation performance. In addition, the longer the foreign object shape, the greater the possibility that the movement of the foreign object will increase and the influence on the insulation performance will increase.

  In order to suppress the movement of foreign matter when operating voltage is applied, foreign matter is removed in the manufacturing process, for example, in the foreign matter management process, so that no long foreign matter is mixed inside the metal container. Strengthen. Furthermore, it is necessary to design the electric field strength on the inner surface of the metal container when an operating voltage is applied so that a small foreign object that cannot be managed does not float and move above the height considered in the design. Here, the height means the distance between the inner surface of the metal container and the foreign material.

  Since the electric field strength on the inner surface of the metal container depends on the distance between the high voltage conductor and the inner surface of the metal container, it is necessary to enlarge the metal container in order to reduce the flying height of the foreign matter. This has been a limiting factor for reducing the size of the sealed insulating device.

  As a method for relieving the constraint on the design due to the foreign material, a technique for neutralizing the influence on the insulation performance by suppressing the movement of the foreign material is known. For example, as disclosed in Patent Documents 1 to 3, a technique (insulating coating technique) is known in which foreign substance behavior is inactivated by an insulating film obtained by coating an insulating material.

  Insulation coating technology works by suppressing the supply of charges from the inner surface of the metal container to the foreign material by coating the inner surface of the metal container of the hermetic insulation device with a highly insulating epoxy resin or the like. It is difficult. When the foreign substance is difficult to move, the electric field on the inner surface of the metal container can be increased, and the sealed container can be made compact.

It is important to form an insulating film that is highly insulating and difficult to peel off, and a method for realizing this has been proposed.
JP 58-111203 A Japanese Patent Laid-Open No. 2-79711 Japanese Patent No. 3028975

  However, the insulating material (coating material) conventionally used for the above insulating film has the following problems.

  In the conventionally proposed coating material, electric field concentration is likely to occur at a site constituted by the foreign material, the insulating gas, and the coating material. When this electric field concentration becomes large, there is a possibility that partial discharge occurs around the foreign matter and charges are supplied to the foreign matter.

  When a partial discharge occurs, this foreign substance suddenly moves over a wide area and affects the insulation performance. If an overvoltage such as a lightning surge penetrates and the electric field on the inner surface of the metal container increases, the possibility of further increasing the electric field at the electric field concentration part cannot be denied, and although the probability is very low, there is a possibility that a foreign object suddenly moves around greatly. . In order to suppress this sudden movement in a wide range, it is necessary to alleviate the electric field concentration between the coating material and the foreign material to suppress the occurrence of partial discharge and electric field radiation.

  Further, the coating materials that have been put to practical use have the following problems in relation to the above problems. In conventional coating materials, since the insulation of the coating material is always high, in addition to suppressing the movement of foreign materials shorter than the length managed in manufacturing at normal operating voltage, the foreign material longer than the length to be controlled in manufacturing In contrast, the movement due to the electric field is suppressed.

  In general, in a sealed insulation apparatus, a test for applying a voltage higher than an operation voltage after assembly, that is, a soundness confirmation test is performed. For that purpose, if a foreign object longer than the length that should be managed in production is missed in the foreign object management process and remains inside the metal container, the foreign object can be detected and removed by an electric field higher than the operating voltage. I have to. The soundness confirmation test ensures thorough foreign matter management.

  As described above, a long foreign object, particularly a foreign object having a length exceeding the management length, has a characteristic that it is easily moved by the action of an electric field. Applying a voltage higher than the operating voltage during the soundness confirmation test has an effect of promptly moving and finding a long foreign object that may move around at the operating voltage. Foreign substances that move around in the container give impact vibration to the inside of the metal container or generate a partial discharge, and can be detected and removed by detecting them.

  However, in the case of an insulating film formed by coating with an insulating material, foreign substances are less likely to move, and the above-described shock vibration and partial discharge are less likely to occur. Therefore, even if a foreign object is present inside the metal container, it may be difficult to find the foreign object.

  On the other hand, even if it is a foreign object that is hard to be supplied with electric charges and does not move at the operating voltage on the surface layer of the insulating film, the possibility that the foreign object will start to move due to mechanical shock vibration associated with the operation of the switching device cannot be denied. In addition, there is no denying the possibility of starting partial discharges due to higher voltages such as lightning impulses.

  If a long foreign object that exceeds the control length starts to move, partial discharge or electric field radiation may occur around the foreign object, and charge may be supplied to the foreign object to further increase the movement of the foreign object. . Therefore, in the soundness confirmation test, if there is a foreign matter larger than the length that should be managed in production, it is desirable to move the foreign matter with certainty.

  However, insulating films that have been put into practical use are often made of an insulating material that has a stable and high insulation property, and the foreign matter is kept in a state of being difficult to move. Making it difficult to find. For this reason, in order to reliably find foreign objects that are longer than the length that should be managed in manufacturing during the soundness confirmation test, additional work such as applying vibration to the metal container is required, and cost reduction is achieved by making the sealed insulation device compact. It is a restriction condition for proceeding.

  In order to alleviate this restriction, it is necessary to easily detect and remove foreign matters that are larger than the existing management length for a high electric field during a soundness confirmation test. On the other hand, with respect to the operating voltage, it is difficult for foreign substances to move, and the development of a technique for improving the insulation performance of the switching device has been an issue.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to control the behavior of foreign matter in a metal container of a hermetic type insulating device, to make the hermetic type insulating device more compact and to provide insulation reliability. It is to improve the performance.

  In order to achieve the above object, a hermetic insulation device according to the present invention can be divided into at least two parts by a high-voltage conductor that extends in the axial direction and can be divided into at least two in the axial direction, and an end flange. Covering the high-voltage conductor while maintaining a gap between the high-voltage conductor and a metal container filled with an insulating gas in the gap, and fixed to be sandwiched between the end flanges on the outer peripheral side A spacer having an insulating member that supports the high-voltage conductor on the side, and an electric field that is formed on the inner surface of the metal container and that acts on the inner surface of the metal container is less than or equal to a predetermined value; And a non-linear resistance film formed so that the electric resistance is low when the electric resistance is higher than a predetermined value.

  Also, the operating method of the hermetic insulation device according to the present invention includes a high voltage conductor that extends in the axial direction and can be divided into at least two in the axial direction, and the high voltage conductor that can be divided into at least two by an end flange. A metal container that covers the high-voltage conductor while maintaining a gap between the gap and an insulating gas filled in the gap, and is fixed so as to be sandwiched between the end flanges on the outer peripheral side and the high voltage on the inner peripheral side. A spacer that supports a conductor and includes an insulating member; and an electric field that is formed on the inner surface of the metal container and acts on the inner surface of the metal container is high when the electric field is below a predetermined value, and is higher than the predetermined value. In a method of operating a hermetic insulation device having a non-linear resistance film formed so that the electrical resistance is sometimes reduced, a voltage is applied to the high-voltage conductor so that the electric field is higher than the predetermined value. And integrity confirmation step of the electric field is characterized by having a a normal operation step of applying a voltage to the high voltage conductor to be equal to or less than the predetermined value.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to control the behavior of the foreign material in the metal container of a sealed insulation apparatus, to make a sealed insulation apparatus more compact, and to improve the insulation reliability.

  Hereinafter, embodiments of a hermetic insulation device according to the present invention will be described with reference to the drawings.

[First Embodiment]
A first embodiment of the hermetic insulation device of the present invention will be described with reference to FIGS. First, the configuration of the hermetic insulation device of this embodiment will be described. FIG. 1 is a partially cutaway schematic longitudinal sectional view showing a part of the hermetic insulation device of the present embodiment.

  The hermetic insulation device of this embodiment includes a metal container 3, a high-voltage conductor 1, and a spacer 4 that can be divided into a plurality of parts in the axial direction.

  The metal container 3 has a substantially cylindrical shape, and is formed so as to be divided and connected into a plurality of sections with a cross section perpendicular to the central axis of the cylinder. The metal container 3 shown in FIG. 1 is an example of a state in which a second metal container 32 and a third metal container 33 are connected in series to both ends of the first metal container 31, respectively. The containers 31, 32 and 33 can be divided.

  An end flange 3 a is formed on the outer periphery of each connecting portion of the metal container 3 that can be divided into a plurality of parts, that is, the first metal container 31, the second metal container 32, and the third metal container 33. When connecting the first to third metal containers 31, 32, 33, these end flanges 3a are fastened by fastening means such as fastening bolts.

The high voltage conductor 1 is inserted in the substantially central part of the metal container 3 along the central axis direction of the cylindrical part. Further, an insulating gas 2 such as SF ₆ gas is sealed outside the high voltage conductor 1 and inside the metal container 3.

  The spacer 4 has an insulating member 4a and is arranged so as to divide the inside of the metal container 3 in a direction perpendicular to the central axis of the cylinder.

  The spacer 4 is fixed so as to be sandwiched by the end flange 3a from both sides. At this time, the metal container 3 is fastened so as to maintain airtightness. The center side of the spacer 4 is formed so as to support the high voltage conductor 1 inserted into the metal container 3.

  A non-linear resistance film 13 having non-linear electrical resistance characteristics is formed on the inner surface of the metal container 3.

  FIG. 2 is an enlarged cross-sectional model view of the II part of FIG. The nonlinear resistance film 13 is formed by applying a resin 18 filled with powder 14 having nonlinear electrical resistance characteristics such as ZnO to the inner surface of the metal container 3 in a film shape.

  The powder 14 of one or more types of nonlinear resistance material filled in the resin 18 is electrically connected in series or in parallel with each other within the resin 18. That is, the powders 14 are connected to each other, and a main path 15 of leakage current is formed inside the resin 18 to form series and parallel electric circuits having non-linear electric resistance characteristics. By forming these electric circuits, a resin 18 having desired nonlinear electric resistance characteristics can be obtained. By adjusting the production conditions such as the filling amount of the powder 14, the resin 18 can obtain desired electrical resistance characteristics.

  By applying the resin 18 adjusted as described above to the inner surface of the metal container 3 in a film shape, the nonlinear resistance film 13 is formed.

  FIG. 3A is a diagram showing the stray capacitance Cg in the cross-sectional view taken along the line III-III in FIG. FIG. 3B is an equivalent circuit diagram showing a current component of a current flowing through the nonlinear resistance film 13 of FIG.

  For example, when an AC voltage is applied to, for example, a high voltage circuit (not shown) of the hermetic insulation device, the nonlinear resistance film 13 is substantially determined by the stray capacitance Cg between the nonlinear resistance film 13 and the high voltage conductor 1. AC voltage acts. As a result, the current flowing into the nonlinear resistance film 13, that is, the current J flowing through the stray capacitance, is divided into the capacitance component Cz and the nonlinear resistance component Rz of the nonlinear resistance film 13. At this time, the voltage acting on the gap of the insulating gas 2 is Vg, and the voltage acting on the nonlinear resistance film 13 is Vz.

  In advance, the electrical resistance characteristics of the nonlinear resistance film 13 may be adjusted by the adjustment method or the like in accordance with the current density flowing into the nonlinear resistance component Rz.

  FIG. 4 is a model diagram showing the electric field concentration portion 10 generated around the foreign matter 5 on the surface layer of the conventional insulating film 13a. FIG. 5 is a model diagram showing an electric field around the foreign material 5 on the surface layer of the nonlinear resistance film 13.

  As shown in FIG. 4, generally, when a foreign substance 5 is present on a film formed on the inner surface of a sealed metal container 3, for example, a surface layer of a conventional insulating film 13 a, an electric field concentrates around the foreign substance 5. The electric field concentration part 10 in which the intervals, that is, the equipotential lines 16 are closely spaced, appears. When the electric field of the electric field concentration portion 10 exceeds the ionization electric field of the insulating gas 2, for example, partial discharge occurs. When a partial discharge occurs in the periphery of the foreign material 5, electric charges are supplied to the foreign material 5, and the foreign material 5 easily moves in the metal container 3. Note that the electric resistance of the insulating film 13a is regarded as infinite.

  The situation in which the foreign material 5 is easy to move may reduce the insulation performance. Furthermore, depending on the material of the foreign matter 5, the magnitude of the electric field of the electric field concentration part 10 may exceed the magnitude of the electron emission electric field of the material of the foreign matter 5, and the foreign matter 5 may be charged and become easier to move.

  Between the film on the inner surface of the metal container 3, for example, between the insulating film 13a and the foreign material 5, the potential difference between the foreign material 5 and the insulating film 13a, the dielectric constant of the insulating gas 2, and an applied voltage having, for example, a commercial frequency ( A current with a density determined by the AC voltage) flows. The current flowing into the insulating film 13a is divided into a capacitance component and a resistance component of the nonlinear resistance film 13 and flows in the film.

  At this time, for example, as shown in FIG. 5, the nonlinear resistance film 13 is formed on the inner surface of the metal container 3. By adjusting the nonlinear resistance film 13 as described above, the electrical resistance value is made lower than the electrical resistance component of the current density determined by the critical electric field or electron emission electric field of the insulating gas 2 and the dielectric constant. Is formed. That is, the electric resistance when the operating voltage is applied to the nonlinear resistance film 13 is adjusted to be lower than the electric resistance of the insulating film 13a.

  At this time, the electric field concentration around the foreign material 5 is relaxed, and the electric field relaxation portion 17 is formed around the foreign material 5. The occurrence of partial discharge can be suppressed by the electric field relaxation portion 17. That is, by reducing the resistance of the non-linear resistance film 13 around the foreign material 5 where the electric field is concentrated, the potential of the peripheral film is brought close to the potential of the foreign material 5 and the interval between the equipotential lines 16 around the foreign material 5 is widened. This relaxes the electric field and suppresses the occurrence of partial discharge and electron emission.

  When the sealed insulating device is in an operating state, it is possible to suppress the movement of the foreign matter 5 existing on the surface layer of the nonlinear resistance film 13 by suppressing the occurrence of partial discharge around the foreign matter 5. For this reason, compared with the case where the conventional insulating film 13a is used, the design electric field of the metal container 3 can be increased, and the metal container 3 can be made more compact.

  FIG. 6 is a graph showing the relationship between the current density and the applied voltage, which is a characteristic of the nonlinear resistance film 13 of the present embodiment.

  In general, a resin having a non-linear resistance characteristic filled with a non-linear resistance material powder 14 has a non-linear non-linear relationship between an applied voltage and a flowing current density as shown in FIG. Yes. The characteristics of the resin filled with the powder 14 are obtained by adjusting the voltage value at the boundary between the high resistance region and the low resistance region, as in the characteristics A, B, and C in FIG. Each can be adjusted to a different value. A voltage a illustrated in FIG. 6 indicates a boundary voltage in which the electric resistance characteristic in the characteristic A changes from the high resistance region to the low resistance region. Similarly, voltage b and voltage c indicate boundary voltages in characteristics B and C, respectively.

  The non-linear resistance film 13 of this embodiment is adjusted to have non-linear resistance characteristics such that the operating voltage V1 is high resistance and the soundness test voltage V2 is low resistance as shown by characteristic B in FIG. . As described above, even if the resistance is high, it is formed lower than the electrical resistance of the conventional insulating film 13a.

  In general, the manufacturing process of the metal container 3 includes a foreign matter management step for removing the foreign matter 5 that is larger than a predetermined reference length (management length). However, in the case where the conventional insulating film 13a is formed on the inner surface of the metal container 3, the foreign matter 5 larger than the control length, that is, the size that should be found and removed in the foreign matter management process in the soundness confirmation test. In some cases, it was difficult to find the foreign matter 5.

  On the other hand, when the foreign substance 5 exists on the surface layer of the nonlinear resistive film 13 as in the characteristic B, as described above, the electric field concentration around the foreign substance 5 is relaxed and acts on the nonlinear resistive film 13. The electric field to be averaged. This averaged electric field has a value close to the electric field on the inner surface of the metal container 3 when the foreign material 5 is not present.

  Therefore, since the foreign substance 5 is kept in a state in which it hardly moves with respect to the operating voltage V1, the design electric field on the inner surface of the metal container 3 during operation can be increased.

  On the contrary, the resistance of the non-linear resistance film 13 becomes small at the voltage V2 at the soundness confirmation test, and the foreign matter 5 at this time is in almost the same state as that directly attached to the metal surface inside the metal container 3. , It becomes easier to be supplied with charge and move easily.

  That is, by setting the design electric field of the inner surface of the metal container 3 corresponding to the voltage V2 at the soundness confirmation test to an electric field in which the foreign substance 5 larger than the management length moves, it is larger than the management length at the time of the soundness confirmation test. The foreign object 5 can be easily moved. This makes it easy to find and remove the foreign material 5.

  FIG. 7 is a graph showing the characteristics of the material time constant of the nonlinear resistance film 13 when the applied voltage is an alternating voltage, and showing the relationship between the time constant of the material and the applied voltage.

  FIG. 8A is a model diagram of the periphery of the nonlinear resistance film 13, where the nonlinear resistance film 13 is formed on the inner surface of the metal container 3 in which the insulating gas 2 is sealed, and the foreign material 5 is formed on the surface layer of the nonlinear resistance film 13. Indicates the state where. FIG. 8B is an equivalent circuit diagram of FIG. FIG. 9 is a graph showing the applied AC voltage during the soundness confirmation test (the voltage V2 during the soundness confirmation test) as a time-series waveform. At a voltage exceeding the absolute value of the boundary voltage V3 or the boundary voltage −V3, the electrical resistance changes from the high resistance region to the low resistance region.

In general, the resin 18 having a nonlinear resistance characteristic filled with the powder 14 of the nonlinear resistance material has a characteristic that the resistance decreases with an applied voltage, for example, as shown in FIG. Therefore, the relationship between the time constant τ determined by the product of the dielectric constant and volume resistivity of the material forming the nonlinear resistance film 13 and the applied voltage is, for example, an inversely proportional relationship as shown in FIG. S in FIG. 7, i.e. the frequency of the τ is the applied AC voltage, for example, shorter than 1/2 of the period T ₂ of the commercial frequency, the higher the applied voltage is the boundary voltage V3 of the resistance characteristic area, the charge to the foreign matter 5 Is easy to be supplied.

  The electric resistance characteristics of the non-linear resistance film 13 can be adjusted as described above, and the dielectric constant of the non-linear resistance film 13 can be adjusted by filling a powdery material having a different dielectric constant such as alumina. It becomes.

When the operating voltage V1 or the voltage V2 during the soundness confirmation test is an alternating voltage, the nonlinear resistance film 13 has an overvoltage (health) that causes the time constant τ determined from its dielectric constant and volume resistivity to act in the soundness confirmation test. during application of sex confirmation test when a voltage V2), is shorter than 1/2 of the period T ₂ of the frequency of the AC voltage (commercial frequency), during operation, it is adjusted to be longer than the period T ₂ ing.

  As shown in FIG. 8, when the foreign material 5 is present on the surface layer of the nonlinear resistance film 13, the electrostatic capacity Cz between the foreign material 5 and the nonlinear resistance film 13 is used in order to supply charges to the foreign material 5. Further, a time determined by the resistance Rz of the nonlinear resistance film 13 is required. This time is the same as the time constant τ of the material forming the nonlinear resistance film 13 described above.

As shown in FIG. 9, when the applied voltage is an AC voltage, the polarity of the applied voltage changes in half the period T ₂ , so the resistance of the non-linear resistance film 13 is lowered and the time constant of the material is reduced. The time T ₁ during which the time decreases becomes shorter than ½ of the period T ₂ of the AC voltage. Charge supply to the foreign body 5 is carried out during this time T _1. That is, as shown in S of FIG. 7, in the region S in which the time constant τ is shorter than ½ of the period T ₂ of the commercial frequency and the applied voltage is higher than the boundary voltage V 3 of the resistance characteristic, the charge is applied to the foreign material 5. Easy to be supplied.

Accordingly, when allowed to act upon integrity confirmation test voltage V2, the time constant τ of the material in order to efficiently supply charge to the foreign body 5 is smaller than 1/2 of the period T ₂ of the least AC voltage must, furthermore, it is desirable that less than time T _1. On the other hand, the operating voltage V1
Since the resistance of the non-linear resistance film 13 is in the high resistance region, the time constant τ becomes long and the charge cannot be efficiently supplied to the foreign material 5.

  When the foreign substance 5 is present on the surface layer of the nonlinear resistance film 13 having the above characteristics, the foreign substance 5 is kept in a state in which it is difficult to move with respect to the electric field corresponding to the operating voltage V1. Therefore, the design electric field of the inner surface of the metal container 3 during operation can be increased.

  On the contrary, the time constant of the nonlinear resistance film 13 becomes smaller with respect to the voltage V2 at the soundness confirmation test, and the foreign matter 5 is easily supplied and charges are easily moved. Therefore, the foreign matter 5 becomes easy to move during the soundness confirmation test. Therefore, the foreign substance 5 can be easily found and removed during the soundness confirmation test.

  As is clear from the above description, the hermetic insulation device of this embodiment is more compact and can improve insulation reliability.

[Second Embodiment]
A second embodiment of the hermetic insulation device according to the present invention will be described with reference to FIGS. 10 and 11.

  FIG. 10 is a graph showing the pressure characteristics of the non-linear resistance film 13 formed on the inner surface of the metal container 3 of the hermetic insulation device of the present embodiment, showing the relationship between the current density and the applied voltage. Compared with the characteristic P1 in FIG. 10, the characteristic P2 shows a state in which the pressure acting on the non-linear resistance film 13 is increased.

  FIG. 11 is an enlarged cross-sectional model diagram illustrating a state before and after pressure is applied to the nonlinear resistance film 13. In addition, illustration of the metal container 3 is abbreviate | omitted in FIG. FIG. 11A shows a state before pressure is applied, that is, before pressurization, and FIG. 11B shows a state after pressurization. The resin thickness d2 after the pressure is applied is an example in which the resin thickness d1 is less than the resin thickness d1 before the pressure action.

  In addition, the structure of the metal container 3 of this embodiment is the same as that of the metal container 3 of 1st Embodiment shown in FIG. 1, and the nonlinear resistance film 13 is formed in the inner surface.

  The non-linear resistance film 13 has an elastic characteristic that allows the amount of strain to be changed by the pressure of the insulating gas 2 sealed in the metal container 3 so that the non-linear resistance characteristic of the non-linear resistance film 13 can be changed by the pressure of the insulating gas 2. It has been adjusted. For example, a resin filled with a powder 14 of a non-linear resistance material is used that has elastic properties such as an elastomer.

  As shown in FIG. 11, by increasing the gas pressure of the insulating gas 2 in the metal container 3, for example, the gas filling pressure, the resin thickness d2 after pressurization is thinner than the resin thickness d1 before applying the gas pressure. Thus, it is possible to increase the number of electrical series connections and the number of parallel connections formed by the non-linear resistance material powder 14 and the like. As a result, the current density for the same applied voltage increases, the resistance decreases, and the time constant τ of the material forming the nonlinear resistance film 13 decreases.

  The hermetic insulation device can usually change the gas pressure of the insulating gas 2 to about 0.7 MPa at the maximum. The elastic properties of resin materials such as elastomers are adjusted by manufacturing conditions such as additives and curing conditions. With respect to the voltage V2 (AC voltage) at the soundness confirmation test, the smaller the time constant τ of the material in the low resistance region, the easier the electric charge is supplied to the foreign material 5 on the surface layer of the non-linear resistance film 13. 5 is easy to move and easy to find.

  As is clear from the above description, the foreign object 5 can be easily found and removed during the soundness confirmation test, and the foreign object 5 can be made difficult to move during operation. It is possible to increase the electric field. As a result, the hermetic insulation device can be made more compact and the insulation reliability can be improved.

[Other Embodiments]
The description of the above embodiment is an example for explaining the present invention, and does not limit the invention described in the claims. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

  For example, in the first and second embodiments, the example in which ZnO is used as the powder 14 has been described, but the present invention is not limited thereto. The present invention can be applied as long as it can obtain the characteristic that the electric resistance decreases when the applied voltage is increased.

It is a partial notch schematic longitudinal cross-sectional view which shows a part of sealed type insulation apparatus of 1st Embodiment which concerns on this invention. FIG. 2 is an enlarged cross-sectional model view of a II part in FIG. 1. (A) is the figure which showed the stray electrostatic capacitance in the III-III arrow cross-sectional view of FIG. 1, (b) is an equivalent circuit diagram which shows the electric current component of the electric current which flows through the nonlinear resistive film of FIG. It is a model figure which shows the state of electric field concentration around the foreign material of the surface layer of the conventional insulating film. It is a model figure which shows the state of the electric field around the foreign material of the surface layer of a nonlinear resistance film. It is the characteristic of the nonlinear resistive film formed in the inner surface of the metal container of the sealed insulation apparatus of 2nd Embodiment which concerns on this invention, Comprising: It is the graph which showed the relationship between an electric current density and an applied voltage. It is the characteristic of the material time constant of the nonlinear resistive film of embodiment of FIG. 1, Comprising: It is the graph which showed the relationship between the time constant of material, and an applied voltage. (A) is a model diagram around the nonlinear resistance film of the embodiment of FIG. 1, and (b) is an equivalent circuit diagram of (a). It is the graph which showed the time-sequential waveform of the applied voltage in the nonlinear resistive film of embodiment of FIG. It is a pressure characteristic of the nonlinear resistive film formed in the inner surface of the metal container of the hermetic insulation device according to the second embodiment of the present invention, and is a graph showing the relationship between the current density and the applied voltage. It is an expanded sectional model figure which showed the state before and behind a pressure acting on the nonlinear resistive film in embodiment of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... High voltage conductor, 2 ... Insulating gas, 3 ... Metal container, 3a ... End flange, 4 ... Spacer, 4a ... Insulating member, 5 ... Foreign material, 10 ... Electric field concentration part, 13 ... Nonlinear resistance film, 14 ... Powder , 15 ... main path of leakage current, 16 ... equipotential line, 17 ... electric field relaxation part, 18 ... resin, 31 ... first metal container, 32 ... second metal container, 33 ... third metal container

Claims (5)

A high voltage conductor extending in the axial direction and splittable into at least two in the axial direction;
A metal container that can be divided into at least two by an end flange, covers the high-voltage conductor while maintaining a gap between the high-voltage conductor, and the gap is filled with an insulating gas;
A spacer which is fixed so as to be sandwiched between the end flanges on the outer peripheral side and supports the high-voltage conductor on the inner peripheral side and includes an insulating member;
It is formed on the inner surface of the metal container so that the electric resistance is high when the electric field acting on the inner surface of the metal container is below a predetermined value, and the electric resistance is low when the electric field is higher than the predetermined value. A non-linear resistive film;
A hermetic insulating device characterized by comprising:   2. The hermetic seal according to claim 1, wherein the non-linear resistance film is filled with powder having a non-linear characteristic of electric resistance, and the powder is electrically connected in series and in parallel to each other. Mold insulation device.   An AC voltage is applied to the high-voltage conductor, and the nonlinear resistance film has a time constant determined by a product of its volume resistivity and dielectric constant, and the period of the AC voltage when the electric field is the predetermined value. 3. The hermetic insulation device according to claim 1, wherein when the electric field is higher than the predetermined value, it is formed to be shorter than at least half of the period. .   2. The non-linear resistance film has elasticity, and is formed such that the electric resistance decreases as the thickness of the non-linear resistance film is reduced by the action of the pressure of the insulating gas. The hermetic insulation device according to any one of claims 3 to 4. A high voltage conductor that extends in the axial direction and can be divided into at least two in the axial direction, and can be divided into at least two by an end flange and covers the high voltage conductor while maintaining a gap between the high voltage conductor and the high voltage conductor. A metal container filled with an insulating gas in the gap, a spacer fixed on the outer peripheral side so as to be sandwiched between the end flanges, supporting the high-voltage conductor on the inner peripheral side, and having an insulating member; and the metal container A non-linear resistance film formed on the inner surface of the metal container so that the electric resistance is high when the electric field acting on the inner surface of the metal container is equal to or less than a predetermined value, and the electric resistance is low when the electric field is higher than the predetermined value. In the operation method of the hermetic insulation device having
A soundness confirmation step of applying a voltage to the high-voltage conductor so that the electric field is higher than the predetermined value;
A normal operation step of applying a voltage to the high-voltage conductor so that the electric field is equal to or less than the predetermined value;
A method for operating a hermetic insulation device, comprising:

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