JP2008141809A - Resin mold insulated conductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a cast article for electric insulation, used in a high pressure gas insulated device and having its metal bare conductor mold insulated, stores the heat generated by conduction-heating in the conductor, to promote a temperature rise in the device, influencing the heat resistance strength of other insulation materials or the like and shortening the insulation distance between the tank inner wall and the mold part surface of the cast article for electric insulation to cause the mold part surface to be a high electric field, with an increased possibility of causing insulation breakage. <P>SOLUTION: The resin mold insulated conductor is configured to have a metal conductor 11, and an insulation layer 12, which is arranged so as to surround the periphery of the metal conductor and has uneven parts 12a for heat dissipation on the surface cast by a mold material prepared by blending an epoxy resin, an acid anhydride hardening agent and an alumina. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a resin-molded insulated conductor that can be preferably used for high voltage equipment such as SF ₆ gas insulation equipment.

In order to protect the environment and save space, high-voltage gas insulation equipment is indispensable. As conventional technologies for downsizing equipment and improving reliability, epoxy compounds, curing agents for epoxy resins that cure the epoxy compounds, silica fillers that retain the insulation of the resins, and rubber particles that increase the strength of the resin SF ₆ gas insulation which is molded by curing under a curing condition in which the resin shrinkage due to the curing reaction is offset by the volume expansion of the matrix resin and the rubber particles. There is a manufacturing method of cast products for high voltage devices (for example, see Patent Document 1). In addition, an insulating spacer that insulates and supports a conductor disposed in a container filled with an insulating gas is formed of an epoxy resin composition containing silica, and the insulating spacer includes a coating layer that covers the surface. The epoxy resin composition containing coating and the coating layer are the same multifunctional epoxy resin, the epoxy equivalent of the multifunctional epoxy resin is 150 to 250, and the coating layer contains a filler excellent in SF ₆ decomposition gas resistance There is an insulating spacer characterized in that (see, for example, Patent Document 2).

JP 2001-135144 A (first page, FIG. 2) JP-A-11-29727 (first page, FIG. 1)

In the prior art as shown in the above-mentioned Patent Document 1, since it has excellent SF ₆ decomposition gas resistance and a low dielectric constant, the insulation design of the gas insulation device becomes easy, and the device is downsized and improved in reliability. Although it can be achieved, since the generated electric field strength is increased, the insulation performance of the cast product for electrical insulation is limited, and there is a problem that downsizing is limited. Further, in the prior art as shown in Patent Document 2, the SF ₆ gas insulated switchgear and the SF ₆ gas insulated conduit air transmission line can be reduced in size, increased in capacity, and improved in reliability. For this reason, there was a problem that miniaturization had a limit. On the other hand, a hybrid insulation technique in which solid insulation and gas insulation are combined and applied to these problems has been studied. The cast product for electrical insulation used here for hybrid insulation is a product obtained by applying mold insulation to the outer periphery of a conventional high-pressure gas that uses a bare metal conductor as a conducting conductor.

  However, in a cast product for electrical insulation in which a bare metal conductor is molded and insulated, the mold insulation serves as a heat insulating material, and the heat generated by energization is stored in the conductor, which promotes the temperature rise of the equipment and other insulating members In the case of compactly designed equipment, the insulation distance between the inner wall of the tank and the mold surface of the cast product for electrical insulation is shortened, and the mold surface becomes a high electric field. There is a problem that the possibility of becoming a starting point of dielectric breakdown increases. In addition, when molded into a long conductor, there is a risk that peeling will occur at the interface between the bare metal conductor and the mold member, or cracks may occur in the mold member due to the thermal stress resulting from the difference in thermal expansion coefficient. was there.

  The present invention has been made to solve the above-described problems of the prior art, and has a high heat radiation effect of heat generated from a metal conductor, and a highly reliable resin-molded insulated conductor that can further reduce the size of the device. The purpose is to obtain.

  The resin-molded insulated conductor according to the present invention is disposed so as to surround the metal conductor and the metal conductor, and is a surface cast by a molding material containing an epoxy resin, an acid anhydride curing agent, and alumina. And an insulating layer having irregularities that help dissipate heat.

  In this invention, the metal conductor is surrounded by an insulating layer having irregularities on the surface cast by a molding material containing an epoxy resin, an acid anhydride curing agent, and alumina. Since the heat conductivity is high and heat is easily dissipated from the surface of the insulating layer, the heat generation of the metal conductor due to energization is hardly stored, and the temperature rise of the device can be suppressed. In addition, since the thermal expansion coefficient of the insulating layer is about the same as that of aluminum, the generation of thermal stress can be reduced, so that peeling or the like can be prevented at the interface with the mold member, and reliability can be improved.

Embodiment 1 FIG.
FIG. 1 shows a gas insulated bus such as a gas switchgear (GIS, GCB, etc.), a gas insulated transformer, etc. using SF ₆ gas as an insulating medium for the resin molded insulated conductor according to the first embodiment for carrying out the present invention. It is sectional drawing which shows the used example typically. In the figure, a resin-molded insulated conductor 1 includes a metal conductor 11 and an insulating layer 12 having a bowl-shaped unevenness 12a on the surface formed by casting so as to surround the metal conductor 11. In this example, the resin-molded insulated conductor 1 is held by a cone-shaped spacer (not shown) in the center of a metal cylindrical tank 2 and hermetically accommodated together with the SF ₆ gas 3. The insulating layer 12 is formed by casting a mold material in which alumina is used as a filler on a base material made of an epoxy resin and an acid anhydride curing agent. The unevenness 12a is formed.

In FIG. 1, both ends of the metal conductor 11 are exposed, but the configuration of the end of the metal conductor 11 is not particularly limited. For example, when passing through adjacent gas compartments separated by a cone-shaped spacer, a shield (not shown) for the joint is attached. It is also possible not to provide the exposed portion. On the other hand, the type of the epoxy resin is not particularly limited, but a bisphenol type epoxy resin can be preferably used from the viewpoint of the characteristics, availability, and handleability of the obtained mold insulator. The molding material to be used is obtained by blending 400 to 500 parts by weight of alumina (Al ₂ O ₃ ) with respect to a total amount of 80 to 120 parts by weight of the bisphenol type epoxy resin and the acid anhydride curing agent.

  The mixing ratio of alumina as a filler is not necessarily limited, but it is less than about 400 parts by weight with respect to 80 to 120 parts by weight of the bisphenol-type epoxy resin and acid anhydride curing agent as the base material. Since the viscosity of the molding material is too low, the blended alumina begins to settle, the expansion coefficient and curing shrinkage of the resulting resin mold body are large, and the cracking property is also deteriorated. On the other hand, when the blending ratio of alumina exceeds about 500 parts by weight, the viscosity of the mixed molding material is too high, and voids are easily generated during operation. Therefore, it is desirable that the mixing ratio of alumina with respect to 80 to 120 parts by weight of the base material is within a range of 400 to 500 parts by weight.

  Hereinafter, production examples will be described more specifically. 66 g of bisphenol type epoxy resin (CY179, manufactured by HANTSMSN), 44 g of bisphenol type epoxy resin (CY184, manufactured by HANTSMSN), 110 g of acid anhydride curing agent (MH700, manufactured by Shin Nippon Science Co., Ltd.), and alumina (M2) as a filler A mixture of 1000 g (manufactured by Fujimi Incorporated) was used as a molding material. A metal conductor 11 is previously incorporated in a casting mold (not shown) and preheated at 130 ° C. Next, the mold material is poured into a preheated casting mold, cured under a predetermined condition (in this example, about 130 ° C., 20 to 24 hours), and then taken out from the casting mold. A resin-molded insulated conductor 1 in which a metal conductor 11 as shown in FIG.

  The thickness of the insulating layer 12 is not particularly limited, but if the thickness is 5 mm or less, the effect is small, and if it is 10 mm or more, the surface electric field is too high and the dielectric strength decreases. It is preferable to select within a range of about 5 to 10 mm. The unevenness 12a is formed in a bowl shape in which a plurality of semicircular peaks formed in the radial direction or radial direction of the metal conductor 11 are continuous in the axial direction of the metal conductor 11, and the shape of the unevenness 12a is as follows. It is not limited to what was illustrated in FIG. For example, peaks and valleys forming irregularities may be provided in a shape extending in parallel to the axial direction of the metal conductor 11, a spiral shape drawing a spiral in the axial direction, or other shapes.

  The resin-molded insulated conductor 1 obtained as described above has a high thermal conductivity of the insulating layer 12 covering the surface of the metal conductor 11, and the surface of the insulating layer 12 is formed by bowl-shaped irregularities 12a. Since the heat from the surface is easily dissipated, the heat generation of the metal conductor 11 due to energization is difficult to store, the temperature rise of the device can be suppressed, and the provision of the insulating layer 12 reduces the size and the size of the device. Cost can be reduced. Moreover, since the thermal expansion coefficient of the insulating layer 12 is approximately the same as that of aluminum, the generation of thermal stress can be reduced, so that peeling or the like can be prevented at the interface with the mold member, and the reliability can be improved. In the case of a bare metal electrode, the minimum breakdown electric field strength tends to decrease from the theoretical breakdown electric field strength due to the area effect, and is particularly noticeable in a high gas pressure region. However, in the hybrid insulation as shown in FIG. It retained 90% or more of the theoretical breakdown electric field strength, and was confirmed to be suitable for high voltage gas insulation equipment such as GIS.

Embodiment 2. FIG.
FIG. 2 is a cross-sectional view schematically showing an example in which the resin-molded insulated conductor according to the second embodiment for carrying out the present invention is used as the same gas-insulated bus as in the first embodiment. In the figure, the first metal material is cast around the metal conductor 11 constituting the resin-molded insulated conductor 1A by a molding material containing the same epoxy resin, acid anhydride curing agent, and alumina as in the first embodiment. An insulating layer 12A and a second insulating layer 13 which is provided so as to surround the first insulating layer 12A, has a dielectric constant smaller than that of the first insulating layer 12A and has irregularities 13a on the surface thereof are cast. Is provided. The second insulating layer 13 is a mold in which forsterite (Mg ₂ SiO ₄ ) is mixed at a blending ratio of 390 to 440 parts by weight with respect to a total amount of 80 to 120 parts by weight of the bisphenol type epoxy resin and the acid anhydride curing agent. It is made of material.

  The blending ratio of the foresterite as the filler is not necessarily limited, but less than about 390 parts by weight with respect to 80 to 120 parts by weight of the bisphenol type epoxy resin and the acid anhydride curing agent as the base material, The viscosity of the mixed mold material is too low, and the blended forsterite will settle, the expansion coefficient and cure shrinkage of the resulting resin mold body will be large, and the cracking property will also deteriorate. On the other hand, when the blending ratio of foresterite exceeds about 440 parts by weight, the viscosity of the mixed molding material is too high, and voids are likely to occur during the operation. Therefore, the blending ratio of foresterite with respect to 80 to 120 parts by weight of the base material is desirably within the range of 390 to 440 parts by weight.

  Specifically, first, a molding material in which 390 to 440 parts by weight of foresterite is mixed with 80 to 120 parts by weight of the same bisphenol type epoxy resin and acid anhydride curing agent as in the first embodiment is not shown. A cylindrical second insulating layer 13 having a bowl-shaped unevenness 13a on the outer peripheral surface is cast by being poured into a preliminary mold and heat-cured. Next, the cylindrical second insulating layer 13 and a metal conductor 11 are incorporated in the center of the second insulating layer 13 (not shown) and preheated at 130 ° C. Next, in the space between the inner peripheral part of the second insulating layer 13 and the outer peripheral part of the metal conductor 11, the same bisphenol type epoxy resin and acid anhydride curing agent as in the first embodiment are added in an amount of 80 to 120 parts by weight. On the other hand, a hybrid in which the metal conductor 11, the first insulating layer 12A, and the second insulating layer 13 are integrally molded by pouring a molding material containing 400 to 500 parts by weight of alumina and curing it under a predetermined condition. A resin molded insulated conductor 1A schematically shown in FIG. 2 is obtained.

The resin-molded insulated conductor 1A according to the second embodiment configured as described above is similar to the first embodiment when the first insulating layer 12A of the first insulating layer 12A is used, for example, when used as a gas insulated bus of an SF ₆ gas insulated device. A mold member made of the second insulating layer 13 having a dielectric constant smaller than that of the first insulating layer 12A is arranged on the outer periphery, and the ridge-like top portion has a smooth curve on the surface of the second insulating layer 13 By forming 13a, in addition to the same effects as in the first embodiment, the concentration of electrolysis on the surface of the mold insulating portion can be further reduced, and the device can be further miniaturized.

By the way, in the description of the first and second embodiments, the case where the present invention is used as the gas insulated bus of the SF ₆ gas insulated device is exemplified. However, the present invention is limited to the gas insulated high voltage device or the gas insulated bus. Instead, it can be widely used as a hybrid insulation system for various high-voltage devices and their attached devices, such as insulated conductors and insulation support members. For example SF ₆ gas insulated apparatus cone of the insulating spacer, the components of the switchgear, can also be used for moisture measuring apparatus of SF ₆ gas-insulated equipment. Further, the casting method is not limited to the above-described examples.

An example using a resin mold insulated conductor according to the first embodiment of the present invention as a gas insulated bus of SF ₆ gas insulated apparatus is a sectional view schematically showing. An example using a resin mold insulated conductor according to the second embodiment of the present invention as a gas insulated bus of SF ₆ gas insulated apparatus is a sectional view schematically showing.

Explanation of symbols

1, 1A resin-molded insulated conductor, 11 metal conductor, 12 insulating layer, 12a unevenness, 12A first insulating layer, 13 second insulating layer, 13a unevenness, 2 tank, 3 SF ₆ gas.

Claims (6)

  A metal conductor, and an insulating layer that is arranged so as to surround the metal conductor, and has an unevenness that assists heat dissipation on a surface cast by a molding material containing an epoxy resin, an acid anhydride curing agent, and alumina. A resin-molded insulated conductor comprising: 2. The molding material according to claim 1, wherein 400 to 500 parts by weight of alumina (Al ₂ O ₃ ) is blended with 80 to 120 parts by weight of a bisphenol type epoxy resin and an acid anhydride curing agent. The resin mold insulated conductor of description.   A first insulating layer which is disposed so as to surround the metal conductor and is cast by a molding material containing an epoxy resin, an acid anhydride curing agent, and alumina; and the first conductor layer. A resin-molded insulated conductor comprising: a second insulating layer provided so as to surround the insulating layer and having irregularities on a surface having a dielectric constant smaller than that of the first insulating layer. 4. The molding material according to claim 3, wherein 400 to 500 parts by weight of alumina (Al ₂ O ₃ ) is blended with 80 to 120 parts by weight of a bisphenol type epoxy resin and an acid anhydride curing agent. The resin molded insulated conductor as described.   The second insulating layer is cast by a molding material containing 390 to 440 parts by weight of forsterite with respect to 80 to 120 parts by weight of a bisphenol type epoxy resin and an acid anhydride curing agent. The resin-molded insulated conductor according to claim 3 or 4.   6. The resin molded insulated conductor according to claim 3, wherein the unevenness is formed in a bowl shape.

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