JP2004071605A - Arrester and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the apprehension of a polymer arrester that the airtightness of the joint between the internal element and insulating container made of a polymer resin of the arrester drops and moisture infiltrates through the joint and lowers the insulation performance of the arrester. <P>SOLUTION: The internal element of the arrester is coated by molding by injecting a silicone resin into a mold after the element is put in the mold and pressurizing the interior of the mold when the silicone resin is heated to the curing temperature of the resin. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lightning arrester using a non-linear resistor mainly composed of zinc oxide and a method for manufacturing the same, and more particularly to a lightning arrester using a resin material (polymer resin) as an insulating container and a method for manufacturing the same.
[0002]
[Prior art]
Generally, when a lightning strike or the like occurs in a power system such as a transmission line or a transmission / substation device, an abnormal voltage (lightning surge) is generated in the system, and there is a possibility that the power device or equipment is damaged and destroyed. In order to protect a power system from such an abnormal voltage, a lightning arrester has been conventionally used. This lightning arrester uses a non-linear resistor that exhibits insulation performance under a normal voltage and exhibits low resistance characteristics when an abnormal voltage is applied, and is connected between the power system and the ground. When an abnormal voltage is generated in the power system, a discharge current flows to the ground through an arrester to limit the abnormal voltage. Then, immediately after the voltage returns to the normal state, the discharge stops, and the lightning arrester returns to the original insulating state.
[0003]
Conventionally, as a structure of such a lightning arrester, one or a plurality of disk-shaped non-linear resistance elements mainly composed of zinc oxide are laminated, and electrodes are arranged at upper and lower ends thereof to form a non-linear resistance laminated body. A plurality of insulating rods are evenly arranged around the non-linear resistance laminated body, and upper and lower portions thereof are fixed to electrodes by insulating nuts to prevent radial displacement thereof, thereby constituting an internal element of the lightning arrester. Further, the internal element is housed in an insulating container, and the upper end of the internal element is covered with a spring via a spring to apply an axial force to the non-linear resistance laminated body including the electrode and fix it.
[0004]
As the insulating container of the lightning arrestor, there are those made of ceramic and those using a polymer resin, and those using a polymer resin are particularly called polymer arresters. In a polymer lightning arrester, as a fixing method of a non-linear resistance laminated body, in addition to a method of holding with an insulating rod, for example, a method of fixing with an insulating tape as in JP-A-1-255437 or a method as in JP-A-10-55904 A method of fixing with an insulating net has been proposed.
[0005]
[Problems to be solved by the invention]
Conventional polymer lightning arresters are constructed by stacking non-linear resistors and fixing them with insulating rods, and house the internal elements of the lightning arrester in an insulating container formed by molding and coating with a polymer resin such as silicone resin. .
[0006]
In such conventional polymer lightning arresters, if the airtightness of the joint surface between the internal element and the polymer resin that is the insulating container deteriorates over a long period of time, moisture will enter from this part, and if there is space inside the lightning arrester There was a concern that moisture would accumulate, weakening the insulation strength and lowering the insulation performance of the lightning arrester. In particular, when the non-linear resistor is fixed with an insulating tape or a mesh, a bubble is easily formed in the overlapping portion of the tape and the mesh, which is a problem in insulation.
[0007]
Also, when the lightning arrester becomes large, the amount of silicone resin increases, and it takes time to cure,
There was also a problem that productivity decreased.
An object of the present invention is to solve the above problems and to obtain a lightning arrester having improved insulation performance without reducing airtightness even after long-term use, and a method for manufacturing the same.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a lightning arrester according to claim 1 is characterized in that one or more non-linear resistors mainly composed of zinc oxide are laminated, and electrode terminals are arranged at both ends thereof, and an insulating support is provided. An internal element is formed by fixing the non-linear resistor and the electrode terminal with the above, and the internal element is placed in a mold, and in a lightning arrester coated with silicone resin, the silicone resin is compression-molded at a curing temperature of the silicone resin. Wherein the inner element is mold-coated.
According to the present invention, the silicone resin is filled up to the gap between the internal elements while maintaining the fluidity of the silicone resin, thereby preventing the formation of gaps and bubbles.
[0009]
The method of manufacturing a lightning arrester according to claim 2 is characterized in that one or more non-linear resistors mainly composed of zinc oxide are laminated, electrode terminals are arranged at both ends thereof, and the non-linear resistance is supported by an insulating support. In a method for manufacturing an arrester in which an internal element is formed by fixing a body and an electrode terminal, and the internal element is placed in a mold and molded with a silicone resin, the silicone resin is compression-molded at a curing temperature of the silicone resin. Characterized by being coated with a mold.
According to the method of the present invention, the silicone resin is filled up to the gap between the internal elements while maintaining the fluidity of the silicone resin, thereby preventing the formation of gaps and bubbles.
[0010]
According to a third aspect of the invention, there is provided a lightning arrester manufacturing method according to the second aspect, wherein the internal element is put into a mold, and a liquid silicone resin is injected into the mold. After sealing the mold, the inside of the mold is pressurized to a high temperature and covered with a mold.
According to the present invention, while maintaining the fluidity of the silicone resin, the silicone resin is filled up to the gap between the internal elements in the sealed mold to prevent the generation of gaps and bubbles.
[0011]
According to a fourth aspect of the present invention, there is provided a method for manufacturing a lightning arrester according to the second or third aspect, wherein the mold is preheated when the silicone resin is injected.
According to this invention, since the mold is preheated in advance, the silicone resin is cured in a short time.
[0012]
According to a fifth aspect of the present invention, there is provided a method for manufacturing a lightning arrester according to the second or third aspect, wherein the internal element is preheated when the silicone resin is injected.
According to this invention, since the mold is preheated in advance, the silicone resin is cured in a short time.
[0013]
The invention of the method for manufacturing an arrester according to claim 6 is characterized in that, in the invention of the method for manufacturing an arrester according to claim 4 or 5, the preheating temperature is lower than the curing temperature of the silicone resin.
According to the present invention, the silicone resin is cured in a short time because the mold or the internal element is preheated in advance.
[0014]
According to a seventh aspect of the present invention, there is provided a method for manufacturing an arrester according to any one of the second to sixth aspects, wherein the silicone resin is gelled, removed from the mold, and cured at a curing temperature of the silicone resin. It is characterized by heat treatment at a higher temperature.
According to the present invention, the curing treatment is performed separately for the reaction for developing the rubber properties of the silicone resin and the reaction for improving the adhesiveness.
[0015]
According to an eighth aspect of the present invention, in the method for manufacturing an arrester according to the fourth or fifth aspect, the preheating temperature is in a range of 70C to 130C.
According to the present invention, the silicone resin is cured in a short time because the mold or the internal element is preheated in the range of 70C to 130C.
[0016]
According to a ninth aspect of the present invention, in the method for manufacturing a lightning arrester according to the seventh aspect, the temperature at which the silicone resin is gelled is set in the range of 80 ° C to 150 ° C, and the heat treatment temperature thereafter. Is in the range of 130 ° C to 180 ° C.
According to the present invention, the curing treatment is performed separately for the reaction for developing the rubber properties of the silicone resin and the reaction for improving the adhesiveness.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a disc-shaped non-linear resistor made of a material containing zinc oxide as a main component, and one or more non-linear resistors 1 are laminated, and two end plates 2a and 2b are provided at both ends thereof. The electrodes 3a and 3b are arranged via the. The electrodes 3a and 3b are connected by bolts 5 with four FRP (glass fiber reinforced plastic) plate-like insulating supports 4 arranged around the non-linear resistor 1 in the laminating direction thereof. I do. Then, as shown in FIG. 1, at least one electrode 3 b is provided with a screw hole 6, a screw 7 is screwed into the screw hole 6, and the pressing plate 2 b is pressed with the screw 7, thereby tightening the laminate of the non-linear resistor 1. It is fixed and constitutes the internal element 8 of the arrester.
[0018]
The insulation container 9 is formed by coating the periphery of the inner element 8 of the lightning arrester configured as described above in a shaded shape with a silicone resin having excellent fluidity. 9a is a cap of the insulating container 9.
[0019]
Next, a description will be given of a manufacturing method for performing mold coating on the silicone resin of the lightning arrester configured as described above. As shown in FIG. 2, the internal element 8 is set in a mold 10 having a hatched shape, a liquid silicone resin 11 is injected into the mold 10, and the temperature in the mold 10 is increased by a heating and pressing device (not shown). Is raised to the curing temperature of the silicone resin, and the silicone resin 11 is cured by applying pressure at the curing temperature of the silicone resin to form a shade shape.
[0020]
For the lightning arrester manufactured by the above method, a salt water boiling test was performed as a long-term reliability verification test. In the test, the lightning arrester body was immersed in 0.1% boiling salt water for 42 hours or more, and the change in electrical characteristics before and after the test was determined by the operation start voltage (voltage generated when a current of 1 mA DC was passed), the limit voltage (10 kA Evaluation was made by measuring the voltage generated when a lightning current was applied. As a result, the decrease in electrical characteristics before and after the test was 1% or less, respectively, and good results were obtained.
[0021]
In the present embodiment, the reason why the boiling resistance is good is considered as follows. In the lightning arrester manufactured in the present embodiment, pressure is applied at a high temperature when the silicone resin 11 is cured. As a result, the silicone resin 11 is compression-molded while maintaining the fluidity before vulcanization, and the gap between the internal elements 8 can be filled with the silicone resin 11. Therefore, there is no place in the polymer material where moisture that has entered such as gaps and air bubbles stays. Further, it is considered that the adhesiveness between the FRP forming the insulating support 4 and the silicone resin 11 was improved, and therefore, the electrical characteristics did not decrease even when immersed in boiling water.
[0022]
Next, a second embodiment of the present invention will be described. As shown in FIG. 2, an internal element 8 is prepared in the same manner as in the first embodiment, placed in a mold 10, and then a liquid silicone resin 11 is injected. The mold 10 has an inlet 12 for injecting the silicone resin 11 and an outlet 13 for removing air from the mold 10. After the injection of the silicone resin 11 is completed, the discharge port 13 is closed, and the injection port 12 is also closed slightly later to seal the inside of the mold 10. By doing so, the internal pressure of the mold 10 can be increased. Thereafter, the temperature in the mold 10 is raised to the curing temperature of the silicone resin, and the silicone resin 11 is cured and coated with a mold, thereby manufacturing an arrester.
[0023]
With respect to the lightning arrester manufactured by the above method, the same salt water boiling test as in the first embodiment was performed. As a result, the decrease in electrical characteristics before and after the test was 1% or less, respectively, and good results were obtained.
[0024]
The reason why the boiling resistance is good in the present embodiment is considered as follows. In the lightning arrester manufactured in the present embodiment, the structure is simple, and the silicone resin 11 is sealed in a mold at high pressure and is heat-molded. Disappears. Further, it is considered that the adhesiveness between the FRP and the silicone resin was improved, and therefore, even when immersed in boiling water, the electrical characteristics did not decrease.
[0025]
Next, a third embodiment of the present invention will be described. As shown in FIG. 2, the internal element 8 manufactured in the same manner as in the first embodiment is placed in a mold 10 preheated to the same temperature as the curing temperature of the silicone resin. Thereafter, as in the second embodiment, the liquid silicone resin 11 is injected, and is press-molded under the curing temperature of the silicone resin to mold-cover, thereby manufacturing a lightning arrester.
[0026]
With respect to the lightning arrester manufactured by the above method, the same salt water boiling test as in the first embodiment was performed. As a result, the decrease in electrical characteristics before and after the test was 1% or less, respectively, and good results were obtained.
[0027]
The reason why the boiling resistance was good in this embodiment is considered to be the same as in the first embodiment or the second embodiment. Further, conventionally, in order to cure the silicone resin 11, it is necessary to raise the temperature of the mold 10 to a predetermined temperature. However, in this embodiment, since the mold 10 is preheated, the curing time may be reduced. Can be. The preheating temperature of the mold 10 may be the same as the curing temperature of the silicone resin 11, but may be set lower than the curing temperature. In particular, when the internal element 8 becomes large, it is desirable to set it lower than the curing temperature. In order to shorten the curing time industrially, the preheating temperature of the mold 10 is desirably 70 ° C. or higher. If the preheating temperature exceeds 130 ° C., the silicone resin 11 starts to cure from the part in contact with the mold 10, so that the preheating temperature is preferably in the range of 70 to 130 ° C.
[0028]
Next, a fourth embodiment of the present invention will be described. As shown in FIG. 2, the internal element 8 manufactured in the same manner as in the first embodiment is preheated to the same temperature as the curing temperature of the silicone resin in advance and placed in the mold 10. Thereafter, as in the second embodiment, the liquid silicone resin 11 is injected, and is press-molded under the curing temperature of the silicone resin to mold-cover, thereby manufacturing a lightning arrester.
[0029]
With respect to the lightning arrester manufactured by the above method, the same salt water boiling test as in the first embodiment was performed. As a result, the decrease in electrical characteristics before and after the test was 1% or less, respectively, and good results were obtained.
[0030]
In this embodiment, the reason why the boiling resistance was good is considered to be substantially the same as in the first embodiment or the second embodiment. If the internal element 8 is not preheated, the silicone resin itself starts to cure before the reaction on the bonding surface with FRP, but if the internal element 8 is preheated, the curing reaction also occurs on the bonding surface. To start, the adhesiveness with FRP is improved. Further, conventionally, in order to cure the silicone resin, it is necessary to raise the temperature of the mold to a predetermined temperature. However, since the internal element 8 is preheated, the curing time can be shortened. The preheating temperature of the internal element 8 may be the same as the curing temperature of the silicone resin, but may be set higher than the curing temperature. In that case, the curing time can be further reduced.
[0031]
Conversely, the preheating temperature of the internal element 8 can be set lower than the curing temperature of the silicone resin. In particular, when the internal components become large, it is desirable to set the temperature lower than the curing temperature because it is possible to prevent the preheating time from becoming unnecessarily long. In order to shorten the curing time industrially, the preheating temperature of the mold 10 is desirably 70 ° C. or higher. If the preheating temperature exceeds 130 ° C., the silicone resin 11 starts to cure from the part in contact with the internal element 8, so that the preheating temperature is preferably in the range of 70 ° C. to 130 ° C.
[0032]
Next, a fifth embodiment of the present invention will be described. As shown in FIG. 2, the internal element 8 manufactured in the same manner as in the first embodiment is placed in a mold 10. Thereafter, as in the second embodiment, the liquid silicone resin 11 is injected, the temperature in the mold 10 is heated to a temperature close to the curing temperature of the silicone resin, and the silicone resin 11 is pressurized. After the silicone resin has gelled, the temperature in the mold 10 is further raised to a temperature higher than the curing temperature, heat treatment is performed, and the mold is coated to manufacture an arrester.
[0033]
With respect to the lightning arrester manufactured by the above method, the same salt water boiling test as in the first embodiment was performed. As a result, the decrease in electrical characteristics before and after the test was 1% or less, respectively, and good results were obtained.
[0034]
The reason why the boiling resistance is good in the present embodiment is considered as follows. In order to cure the silicone resin 11, it is desirable to perform the treatment at a high temperature. However, on the other hand, the curing starts from the silicone resin 11 that has come into contact with the mold 10, and the progress of the reaction at the time of molding varies, which is not preferable. The curing reaction of the silicone resin 11 includes a reaction in which the silicone resin 11 itself gels to exhibit rubber properties and a reaction in which the adhesiveness is improved. By dividing these reactions, firstly, the temperature of the curing reaction is lowered to reduce the variation in the reaction progress during molding, and after gelation, the temperature of the curing reaction is raised to improve the adhesiveness, so that the reaction is improved. Insulating container 9 having no variation, that is, no defects such as cavities, and having good adhesiveness can be obtained.
[0035]
In the present embodiment, the heat treatment was performed while the internal element 8 was kept in the mold 10. However, when the silicone resin 11 was gelled, the silicone resin 11 was formed into a shape. Heat treatment can also be performed. Thereby, the mold 10 can be used efficiently.
[0036]
Regarding the reaction temperature at which the silicone resin 11 itself gels and exhibits rubber properties, gelling does not proceed below 80 ° C., and if the reaction temperature exceeds 150 ° C., the reaction occurs rapidly and molding becomes poor. It is desirable that the temperature be in the range of 150C to 150C. Regarding the subsequent heat treatment temperature, if the temperature is lower than 130 ° C., the reaction takes a long time, and if the heat treatment temperature exceeds 180 ° C., the mechanical strength of the FRP is reduced. .
[0037]
【The invention's effect】
As described above, according to the present invention, one or more non-linear resistors mainly composed of zinc oxide are laminated, electrode terminals are arranged at both ends thereof, and the non-linear resistors and the electrode terminals are placed on an insulating support. The lightning arrester and the method of manufacturing the lightning arrester, in which the internal element is fixed in a mold, and the internal element is placed in a mold and molded with a silicone resin, the compression molding of the silicone resin is performed at a curing temperature of the silicone resin. Since the resin is mold-coated, it is possible to obtain a lightning arrester with improved insulation performance and a method for manufacturing the lightning arrester without deterioration in airtightness even after long-term use.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing the structure of a lightning arrester manufactured according to the present invention.
FIG. 2 is a schematic cross-sectional view for explaining a method for manufacturing a lightning arrester of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Non-linear resistor, 2a, 2b ... This plate, 3a, 3b ... Electrode, 4 ... Insulating support, 5 ... Bolt, 6 ... Screw hole, 7 ... Tome bolt, 8 ... Internal element, 9 ... Insulating container, 10 ... mold, 11 ... silicone resin, 12 ... inlet, 13 ... outlet.

Claims (9)

One or a plurality of non-linear resistors mainly composed of zinc oxide are laminated, electrode terminals are arranged at both ends thereof, and the non-linear resistors and the electrode terminals are fixed by an insulating support to constitute an internal element. A lightning arrester in which the internal element is placed in a mold and molded with a silicone resin, wherein the internal element is mold-coated with a silicone resin compression-molded at a curing temperature of the silicone resin. One or a plurality of non-linear resistors mainly composed of zinc oxide are laminated, electrode terminals are arranged at both ends thereof, and the non-linear resistors and the electrode terminals are fixed by an insulating support to constitute an internal element. A method for manufacturing a lightning arrester, wherein the internal element is placed in a mold and molded with a silicone resin, wherein the silicone resin is compression-molded at a curing temperature of the silicone resin and molded. 3. The lightning arrester according to claim 2, wherein the inner element is put into a mold, a liquid silicone resin is injected into the mold, the inside of the mold is sealed, and the inside of the mold is pressurized and heated to mold. Production method. The method for manufacturing a lightning arrester according to claim 2 or 3, wherein the mold is preheated when the silicone resin is injected. 4. The method for manufacturing a lightning arrester according to claim 2, wherein the internal element is preheated when the silicone resin is injected. 6. The method for manufacturing an arrester according to claim 4, wherein the preheating temperature is lower than a curing temperature of the silicone resin. 7. The method for manufacturing a lightning arrester according to claim 2, wherein the silicone resin is gelled, removed from the mold, and heat-treated at a temperature higher than the curing temperature of the silicone resin. The method for manufacturing an arrester according to claim 4 or 5, wherein the preheating temperature is in a range of 70C to 130C. The method for manufacturing a lightning arrester according to claim 7, wherein the temperature at which the silicone resin is gelled is in the range of 80C to 150C, and the subsequent heat treatment temperature is in the range of 130C to 180C.

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