JPH11126527A - Insulating spacer and method and apparatus for manufacturing thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulating spacer with high reliability and a method and an apparatus for manufacturing the insulating spacer by optimizing the dielectric strength margin of a material for the insulating spacer corresponding to the practical electric field intensity and reducing the extent of variations of the dielectric strength margin and making the dispersion width even. SOLUTION: Three components, which are a thermosetting resin, an inorganic filler, and a low dielectric inorganic filler having a lower dielectric constant than that of the inorganic filler, are dispersed, kneaded, degassed, and extruded into a string-like extruded product which is not yet curved and kept in molten state in order to control the dielectric constant of this material to be high in the high voltage side, which is the metal tool 8 side for connecting a conductor, to be low in the metal flange 9 side, which is the earth side, and to be approximately linearly changed between both sides. After that, the extruded product is spirally coiled in the lower die of spacer dies as to fill the lower die and then the resultant lower die and an upper die of the spacer dies are fastened to cure and mold the coiled product and the obtained product is finally parted from the dies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating spacer used for supporting a conductor in a metal container of a gas insulating device of a power device, a method of manufacturing the same, and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art In an existing gas insulating apparatus, as shown in FIG. 13, an insulating spacer 1 is provided with a high voltage in a sealed metal container 3 in which a sulfur hexafluoride gas 2 is sealed at a predetermined pressure as an insulating gas. The applied conductor 4 is connected to a metal container wall 5 at the ground potential.
It is used as a pressure wall for securing and supporting and fixing the electrical insulation between the sealing chambers and as a pressure wall for the compartments of the sealed chambers 6 and 7. Therefore, electrical insulation performance, mechanical structural strength performance, etc. are required. . As a single product, it has the appearance as shown in FIG. 14, in which a metal part 9 for connecting a conductor is provided at the center, a metal flange 9 for connection with the above-mentioned closed metal container is provided at the outer part, and a thermosetting resin such as epoxy resin. This is a molded product integrally embedded in the resin 10.

Conventionally, as shown in FIG. 15, this insulating spacer is, for example, 200 to 300 parts per 100 parts of epoxy resin.
Parts of an alumina inorganic filler and an additive such as a hardener are added, and under heating, the mixed, defoamed, and liquefied material 10 is passed through a valve 11 into a mold 13 placed in a vacuum chamber 12 from a gate 14. It is manufactured by casting, filling, returning to atmospheric pressure, heating and curing for a predetermined time, then opening the mold in the direction of the arrow in the drawing, and then aging. The above-described conductor connection metal fitting 8 and metal flange 9 are inserted into a metal mold 13 before material casting, and are integrally fixed together with the material 10 as a result of molding.

[0004]

As shown in FIG. 16, in the insulating spacer manufactured by the conventional method, the dielectric constant of the material at each position in the spacer is determined by the limitation of the molding method.
Of course, it has a constant value. FIG. 17 shows equipotential lines (indicated by dotted lines, and the value on the right is each potential) when an insulating spacer with a constant dielectric constant of 6.4 is attached to the equipment and an impulse voltage of 750 kV is applied to the conductor 4. The following shows an example of the analysis result of (Value). From the figure, it can be seen that the potential line 15 becomes denser near the conductor 4 side and becomes sparser toward the metal container wall 5 side. In other words, it can be said that the electric field strength is high in a dense place and low in a sparse place.

From the viewpoint of material design, since the conventional spacer material is a uniform material, electric field strength strength (dielectric strength) is required only at a portion close to the conductor side, and close to the metal container wall side. The portion has a margin of extra electric field strength proof strength compared with the conductor side, and as a result, the latter material can be said to be used sufficiently effectively in the material design for electrical insulation. Absent. Therefore, the present invention eliminates the extra tolerance of the dielectric strength of such a material, and effectively utilizes the spacer material. As a result, the same insulating performance as that of the conventional method can be satisfied, and a more compact and material-saving material can be obtained. It is an object of the present invention to provide an insulating spacer, a method for manufacturing the same, and an apparatus for manufacturing the same.

[0006]

According to the insulating spacer of the present invention, an inorganic filler, a low dielectric inorganic filler having a lower dielectric constant than the inorganic filler, a main agent and a curing agent are integrally mixed. The dielectric constant of the material between the high voltage side and the ground side is changed by changing the weight ratio between the inorganic filler and the low dielectric inorganic filler formed of a granular or flake-shaped thermosetting resin. Thus, the high voltage side is configured to maintain a higher dielectric constant than the ground side. In the method of the present invention, the above-mentioned object is achieved by a molding method completely different from the conventional casting molding method.
It is composed of the following multiple steps. The case where the dielectric constant is changed linearly will be described below, but the case where the dielectric constant is changed non-linearly according to the spacer shape is also conceivable. A granulated or flake-shaped thermosetting resin in which a main agent and a curing agent are integrally mixed, an inorganic filler, and a low-dielectric inorganic filler having a lower dielectric constant than the above-mentioned inorganic filler. The total weight of the inorganic filler and the low dielectric inorganic filler and the weight ratio of the former thermosetting resin are always kept constant, and the weight ratio of the inorganic filler and the low dielectric inorganic filler is kept constant. A three-party supply step so as to linearly change within a predetermined time, and the supplied three-party material is dispersed, kneaded, deaerated and uncured, and a step of obtaining a string-like extruded product in a molten state, The string-shaped extruded product is started under the vacuum reduced pressure from the vicinity of the conductor connection fitting set at the center of the lower mold of the insulating spacer molding die, and is sequentially spirally filled and supplied. After filling up the metal flange installed in the Removing the completed lower mold from the vacuum chamber by returning the pressure to atmospheric pressure, and heating the lower mold in which a predetermined amount of the string-shaped extruded product is supplied and supplied, to which the upper mold of the spacer mold is attached. The mold is introduced into the press machine, and the mold is closed by closing the press machine. At the start of the O-ring airtight state during the mold clamping, the mold clamping is temporarily stopped, and the air in the mold is evacuated. Perform mold clamping with a press machine,
The extruded product charged for a predetermined time is cured by pressing pressure and heating, then the inside of the mold is returned to atmospheric pressure, the mold is opened, and the insulating spacer molded product in which the material dielectric constant gradually changes linearly by the process of releasing the mold. It is characterized by obtaining. And the weight ratio of the inorganic filler and the low dielectric inorganic filler of the extruded product,
It is characterized in that it changes linearly between the start of injection and the minimum, immediately before the end of injection, and to the minimum immediately before the end of injection.

Further, in the apparatus of the present invention, there are provided an apparatus for adjusting and supplying a thermosetting resin, an inorganic filler and a low dielectric inorganic filler, an extruder for obtaining a cord-like extruded product, And an XY stage for filling the string-shaped extruded product into the lower mold in a spiral under vacuum in a vacuum and an XY stage. And a heating press for causing the heating press.

According to the present invention, the dielectric constant at each material position in the spacer is high on the side of the conductor connection fitting, low on the side of the metal flange, and varies substantially linearly between them.
Is expected to be obtained. From this, because the electric field strength is proportional to the reciprocal of the dielectric constant of the material, the present invention,
In the conventional equipotential line group of FIG. 17, the dense portion near the conductor connection fitting has a sparse effect, and the sparse portion near the metal flange has a reverse effect. The former leads to a reduction in the electric field strength, and the latter leads to a reduction in the margin of the extra electric field strength of the material. In this way, the equipotential line group is made equal in pitch, and the electric field intensity becomes constant on average at each material position of the spacer. As a result, the dielectric strength margin of the material is optimized and its variation is improved. The width can be reduced and made constant. The insulation spacer manufactured according to the present invention can use a higher voltage when the spacer has the same shape as the conventional one, and can reduce the outer diameter of the spacer when the same rated voltage specification as the conventional one is used. Compactness and material saving are realized. In addition, at each material position in the spacer, in order to keep the weight ratio of the total amount of the inorganic filler and the thermosetting resin constant, two kinds of inorganic fillers having similar average particle size, particle size distribution and the like are used. It goes without saying that the spacer of the present invention has mechanical strength equal to that of the conventional product.

[0009]

FIG. 1 shows an insulating spacer 9 according to the present invention.
0 and a graph showing the relationship between the dielectric constant of the material and each position of the insulating spacer 90. The insulating spacer 90 includes a conductor connecting metal fitting 8 for insulating and supporting a conductor to which a high voltage is applied, a metal flange 9 for attaching and fixing to a metal container on the ground side, and an insulating member 19. According to the present invention, the insulating member 19 is formed by granulating or flake-like thermosetting in which an inorganic filler, a low-dielectric inorganic filler having a lower dielectric constant than the inorganic filler, a main agent and a curing agent are integrally mixed. By forming a three-component mixture of the conductive resin, and by changing the weight ratio of the inorganic filler and the low dielectric inorganic filler, as a result, as shown in the graph,
The dielectric constant of the material on the high voltage side and that of the ground side are changed so that the high voltage side has a higher dielectric constant than the ground side.
Hereinafter, an example of an embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 2 shows the appearance of an apparatus for obtaining the cord-shaped extruded product 20. The apparatus is composed of three material supply devices 30,
It comprises an extruder 40 for dispersing, kneading, degassing and melting the supplied materials 31 and 32 and continuously forming the cord-like extruded product 20. FIG. 3 is a diagram illustrating the operation principle of the material supply devices 30, 31, and 32. The material 34 put into the hopper 33 is fed to the belt conveyor 3 by rotating blades 35 directly connected to the electric motor.
6 and is conveyed in the direction of arrow A by the roller 37 to which the electric motor is directly connected and the roller 38 for simple rotation transmission. The amount of material transported per unit time is determined by rotating blade 35
It goes without saying that the rotation speed is determined by the rotation speed of each of the wheels 37. FIG. 4 is a diagram illustrating the principle of operation of the extruder 40. When the material is introduced into the inlet 41, the material is dispersed, kneaded, and moved toward the left side of the drawing by the rotation of the first-stage screw 42, and is gradually melted by the heater 43. To reach. The rotation of the screw 42 is performed by rotating the electric motor 45 through a speed reducer 46 and a transmission device 47 such as a belt or a pulley. In the vacuum chamber 44, deaeration of air, decomposed gas, and the like in the material is performed, and the material is subsequently sent to a second-stage screw 48, where it is completely melted by a heater 49.
The extruded product 20 is continuously extruded from the head 50 as a string-shaped extruded product 20. Similarly, the rotation of the screw 48 is controlled by the electric motor 51,
This is performed by the speed reducer 52 and the transmission 53.

In FIG. 2, material supply devices 30, 3
A supply device for granules or flakes of a thermosetting resin material in which a main agent and a curing agent are already mixed together, an alumina powder as an inorganic filler, and a silica powder as a low dielectric inorganic filler. And the input port 41 of the three materials
As shown in FIG. 5, the relationship between the amounts of the fillers added is such that the total amount of the alumina and silica fillers is constant at 300 parts with respect to 100 parts of the resin material, and the two filler amounts are linearly adjusted as shown in the figure. The amount of material transported per unit time of the screws 42, 48 of the extruder and the material supply devices 30, 31,
32 and the belt conveyor 36
It is assumed that the rotational speed of the driving roller 37 is synchronously controlled. Also, the amount of the whole cord-like extruded product needs to be slightly larger than the lower mold cavity volume to be described later, so that it is also satisfied by the synchronous control.

As described above, the alumina powder used as the filler has a dielectric constant of 9.3 as a single product, and the silica powder has a dielectric constant of 4.
5, the permittivity of the obtained extruded string-shaped product 20 is as follows, assuming that the permittivity of the thermosetting resin material used is 2.8.
As shown in FIG. 6, it decreases linearly.

Next, as shown in FIG. 7, a lower mold 60 of a spacer mold heated to a predetermined temperature is placed on an XY stage 61, and the cord-like extruded product 20 is moved to a lower mold. 60 is started. Injection is to prevent air voids from entering the molded product.
As shown in FIG. 8, the process is performed in a vacuum chamber 62 evacuated to a predetermined vacuum pressure. FIG. 9 shows details of the introduction. FIG.
As shown in FIG.
Along the melted string-shaped extruded product 20 so as to be close to the conductor-fitting metal fitting 8 thus set. The XY stage is adjusted and operated so that the cord-shaped extruded product 20 sequentially spirals, and reaches FIG. FIG. 6C shows the lower die 60 which has been inserted into the vicinity of the metal flange 9 which has also been inserted in advance. FIG. 14C shows the end of the charging. From figure (a)
It is desired that the total amount of the cord-shaped extruded product from (b) to (c) be slightly increased so as not to be insufficient in the total volume of the cavity of the lower die 60. The amount of the cord-shaped extruded product per unit time, the method of operating the lower mold by the XY stage, the total charging amount, and the judgment at the end of the charging are calculated in advance from the total volume of the lower mold cavity, and are synchronized with each other. It shall be satisfied by control. The lower mold that has been charged is returned to the atmospheric pressure in the vacuum chamber 62 and is taken out.

Subsequently, as shown in FIG. 10, a spacer lower die into which a predetermined amount of molten string-like extruded product shown in FIG. Upper spacer 73, lower heating plate 74, lower moving plate 75 attached to plate 72
Press machine 7 including a hydraulic cylinder rod 76
0 on the lower heating plate 74. This is schematically shown in FIG. Here, the hatched portion is the string-shaped extruded product 20 that has been put in. Next, the press 70 is operated to perform mold clamping, and the process proceeds to FIG. Upper mold 73 and lower mold 6
When the airtight state is started via the O-ring 77, the air in the mold is evacuated from the through hole 78 provided in the upper mold. After a predetermined degree of vacuum is achieved, final mold clamping is performed, and the process proceeds to FIG. The material 79 charged a little more protrudes from the cavity, and after a predetermined time at a predetermined temperature, the charged material 8
0 solidifies for curing. Thereafter, air is introduced from another through hole 81 provided in the upper die, the die is opened, the molded product is released, and burrs such as material 79 are removed and finished. Obtainable.

As shown in FIG. 1, an insulating spacer 90 manufactured according to the manufacturing method of the present invention has a high dielectric constant of the material on the side of the conductor connection fitting 8 on the high voltage side, and has a high dielectric constant on the ground side. It is expected that a certain metal flange 9 side is low and changes almost linearly therebetween. FIG. 12 shows the result of a numerical analysis assuming such a case. The results show that the equipotential lines are arranged at an equal pitch, and that the electric field intensity is almost constant at each material position in the insulating spacer.
In the step of obtaining the cord-shaped extruded product 20, the step of charging and filling the same into the lower mold 60, and the step of hardening the lower mold together with the upper mold 73 with the heating press 70, vacuum degassing by vacuuming, It goes without saying that the insulating spacer 90 to be manufactured does not include any voids that cause electrical defects due to the compression process.

[00015]

According to the present invention, when a high voltage is applied to the conductor connection fitting, the equipotential lines in the insulating spacer material are arranged at an equal pitch, and the electric field intensity becomes constant. ,
As a result, the dielectric strength margin of the material can be optimized, and the variation width can be reduced and fixed, and a highly reliable insulating spacer can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of an insulating spacer according to the present invention.

FIG. 2 is a diagram illustrating an example of a supply device and an extruder according to the present invention.

FIG. 3 is a diagram showing an example of a supply device of the present invention.

FIG. 4 is a view showing one example of an extruder of the present invention.

FIG. 5 is a diagram showing an example of an addition ratio of an inorganic filler and a low dielectric inorganic filler to the thermosetting resin of the present invention.

FIG. 6 is a diagram showing an example of a change in the dielectric constant of a cord-shaped extruded product of the present invention.

FIG. 7 is a diagram showing a manufacturing process of the present invention.

FIG. 8 is a diagram showing a manufacturing process of the present invention.

FIG. 9 is a diagram showing a manufacturing process of the present invention.

FIG. 10 is a diagram showing a manufacturing process of the present invention.

FIG. 11 is a diagram showing a manufacturing process of the present invention.

FIG. 12 is a diagram showing an example of a numerical analysis of the insulating spacer of the present invention.

FIG. 13 is a diagram showing a device assembling configuration of a conventional insulating spacer.

FIG. 14 is a diagram showing an example of the appearance of a conventional insulating spacer.

FIG. 15 is a diagram showing an example of a conventional casting method.

FIG. 16 is a diagram showing an example of a material dielectric constant of an insulating spacer formed by a conventional casting method.

FIG. 17 is a diagram showing an example of numerical analysis of an insulating spacer formed by a conventional casting method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 8 Conductor connection metal fitting 9 Metal flange 19 Insulating member 20 String-shaped extruded product 30, 31, 32 Supplying device 40 Extruder 60 Lower mold for insulating spacer molding die 61 XY stage 62 Vacuum chamber Reference Signs List 70 Heating press machine 73 Upper die for insulating spacer molding 77 O-ring 90 Insulating spacer

Claims (4)

[Claims] 1. An insulating spacer, which is housed in a metal container of a gas insulating device and insulates and supports a conductor to which a high voltage is applied, comprises an inorganic filler and a low dielectric material having a lower dielectric constant than the inorganic filler. And a thermosetting resin in the form of granules or flakes in which a base material and a curing agent are integrally mixed, and the weight ratio of the inorganic filler to the low dielectric inorganic filler is changed. An insulating spacer characterized in that the dielectric constant of a material between the high voltage side and the ground side is changed so that the high voltage side has a higher dielectric constant than the ground side. 2. The insulating spacer according to claim 1, which is housed in a metal container of a gas insulating device, wherein the total amount of the inorganic filler and the low dielectric inorganic filler having a lower dielectric constant than the inorganic filler is: The weight ratio of the thermosetting resin in the form of granules or flakes in which the main agent and the curing agent are integrally mixed is kept constant, and the weight of the inorganic filler and the low dielectric inorganic filler is kept constant. A three-part supply step in which the ratio is changed linearly within a predetermined time; and a step of dispersing, kneading, and degassing the supplied three-part material to obtain an uncured, molten, string-like extruded product. And the string-shaped extruded product is started under the vacuum reduced pressure from the vicinity of the conductor connection fitting set at the center of the lower mold of the insulating spacer molding die, and is sequentially spirally filled and supplied. Fill up to the metal flange installed around the cavity The the was finished turned ends and the lower vacuum chamber by returning to the atmospheric pressure - taking out from the lower die string-like extrudate was filled with a predetermined amount supply, space -
The mold is introduced into a heating press equipped with an upper mold, and the mold is closed by closing the press.
-At the start of the ring airtight state, the mold clamping is temporarily interrupted, the air in the mold is evacuated, and then the mold is clamped by the final press machine. A method of manufacturing an insulating spacer wherein the dielectric constant of an insulating member forming a molded product is gradually changed linearly by a process of curing, then returning the inside of the mold to atmospheric pressure, opening the mold, and releasing the mold. Method. 3. The extruded product according to claim 2, wherein the weight ratio of the inorganic filler and the low-dielectric inorganic filler is maximized at the start of charging, minimized immediately before the end of charging, and minimized. A method for manufacturing an insulating spacer, characterized in that the interval is changed linearly. 4. An apparatus for adjusting and supplying a thermosetting resin, an inorganic filler and a low-dielectric inorganic filler having a lower dielectric constant than the inorganic filler, and an extruder for obtaining a cord-like extruded product. A mold for filling and molding a material, a vacuum chamber for circulating the cord-shaped extruded product into a lower mold in a spiral shape under vacuum, an XY stage, and the cord-shaped extruded product. And a heating press for heat-compressing and hardening the resin.