JP3437317B2 - Conductive insulator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive insulator used for supporting electric wires, disconnecting switches and the like. More specifically, the present invention relates to a conductive insulator having a conduction function between an insulator main body and a metal fitting, which are joined via a Portland cement material as a cement material having high electric resistance.

[0002]

2. Description of the Related Art When corona discharge occurs due to stains on the surface of an insulator, noise interference occurs in the surrounding radio and television. In order to prevent this, a so-called conductive insulator is known. In this conductive porcelain, a glaze having conductivity (hereinafter referred to as a conductive glaze) is applied to the surface of the porcelain porcelain body, and a means for ensuring conduction is provided between the metal fitting and the conductive glaze layer. Then, a certain amount of current can be passed between the metal fitting and the conductive glaze layer. Various configurations have been proposed so far in order to secure the continuity. less than,
What was carried out at the base of the station post insulator which is one of the rod-shaped insulators will be described.

For example, as shown in FIG. 11, it is known that the insulator body and the metal fitting are electrically connected to each other by a metal spraying method. Specifically, the conductive glaze layer 31 is formed on the outer peripheral surface of the porcelain body 30, and the metal fitting 33 is fixed to the end of the conductive glaze layer 31 via the cement material 32. The conductive metal 34 is sprayed onto the end face and each surface of the metal fitting 33 so that the conductive glaze layer 3
The electrical connection between 1 and the metal fitting 33 is achieved. In the figure, 35 and 36 respectively indicate an insulating sand and an insulating coating.

Further, as shown in FIG. 12, a method using a metal connection method is known. Specifically, conductive paint 38 is applied to the end face of the porcelain body 30 and the conductive glaze layer 31 provided in the sand portion, and the conductive paint 38 and the metal fitting 33 are connected by a conductive metal 39 to achieve conduction. There is. In this case, a coil spring is used as the conductive metal 39.

Further, although not shown, as a conductive cement method, carbon is mixed into the cement material between the porcelain body and the metal fitting as a conductive material, for example, carbon, to achieve conduction between the porcelain body and the metal fitting. Things are known.

[0006]

However, in the metal spraying method shown in FIG. 11, a metallikon using lead as the conductive metal 34 is generally adopted. Therefore, due to the handling of the metallikon during the manufacturing of the insulator,
There was a risk that the worker would be affected by lead-related diseases.
Further, in order to prevent the surface of the metal 34 from being exposed to the air and rusting, after the metal is sprayed, the rust preventive coating 4 is further added.
0 was applied. As described above, the number of steps of spraying the conductive metal 34 and the step of coating the anticorrosion coating 40 is increased in the manufacturing process, and the manufacturing cost is increased in combination with the material cost of the conductive metal material such as metallikon and the anticorrosion coating material.

In the metal connection method shown in FIG. 12, the water contained in the cement material 32 easily corrodes the metal 39. Due to this rust, there was a possibility that conduction failure would occur. In addition, as shown in FIG. 12, a sponge 41 is arranged to block moisture from the cement material 32, and a conductive paint 38 is applied to the porcelain 30 and the conductive paint 38 for conduction between the metal 39 and the conductive glaze layer 31. It was applied to the surface of the conductive glaze layer 31 and a part of the metal surface was exposed to measure conductivity. For this reason, the structure is complicated and it is difficult to assemble at the time of manufacturing.

Further, in the conductive cement method, since the cement material contains carbon, the overall strength of the cement material is lowered and the mechanical strength of the insulator is lowered.
Further, when carbon is mixed in the cement material, it is necessary to set a large water ratio with respect to the cement material, so that the above-mentioned decrease in cement strength is further increased. Moreover, since the cement material contains a large amount of water, the drying shrinkage rate becomes large, and the mounting strength of the metal fitting is unavoidably reduced. In addition, carbon mixed in the cement material,
A battery action is generated between the metal and the zinc plating layer on the surface of the metal fitting buried in the cement material. Therefore, rust occurs on the metal fittings,
The stress due to the increase in volume caused porcelain cracks.

As mentioned above, each conduction method has various serious problems. Therefore, in order to solve these problems, a conduction method using a cement material having a high electric resistance can be considered. That is, as a cement material having a high electric resistance, for example, the electrical conductivity due to the dry-wet equilibrium water content of the Portland cement material is utilized to electrically connect the conductive glaze and the metal fitting.

However, the Portland cement material shrinks when the degree of dryness increases, and as a result, a gap occurs between the Portland cement material and the conductive glaze layer on the surface of the insulator, which causes a minute void between the two. For this reason, a large potential difference is generated between the cement end portion and the conductive glaze layer facing the cement end portion, and an extremely large corona discharge is generated during this period. The occurrence of this corona discharge impairs the original function of the conductive insulator.

Therefore, in the continuity method using the Portland cement material, it has not been practically possible to replace the prior art. The present invention has been made by paying attention to such problems existing in the conventional art.
The purpose is that there is no problem of worker poisoning,
It is an object of the present invention to provide a conductive insulator which has a simple structure and is easy to manufacture and which can ensure the conductivity of a cement material having a high electric resistance at a practical use level.

Another object of the present invention is to provide a conductive insulator capable of preventing the generation of rust due to the chemical reaction between the surface of the metal fitting and the cement during cement curing. Further, another purpose is to secure the strength of the insulator even if the strength of the insulator cannot be maintained due to the difference between the coefficient of thermal expansion of the insulator body and the coefficient of thermal expansion of the conductive glaze layer formed on the peripheral surface thereof. It is possible to provide a conductive insulator capable of exhibiting electrical conductivity.

[0013]

In order to achieve the above object, in the invention according to claim 1, a second conductive layer is provided on at least a part of the surface of the insulator body buried in the cement material. only Rutotomoni, conductive sand grains on the second conductive layer
A sand part made of a child is provided, and the second conductive layer and the front part are provided.
A conductive coating that is softer than the second conductive layer that coats the sand portion is formed, and the second conductive layer is electrically connected to the first conductive layer.

[0014]

According to a second aspect of the present invention, in the first aspect of the present invention, the second conductive layer is provided at least near a surface portion of the cement material exposed to the outside. There is something.

According to a third aspect of the present invention, in the invention according to the first or second aspect, the second conductive layer is at least outside the cylindrical insulator main body buried in the cement material.
It is provided on the peripheral surface .

In the invention described in claim 4 , the inventions according to claims 1 to
In the invention according to any one of claims 3 to 3, the conductive coating has alkali resistance. According to a fifth aspect of the invention, in the invention according to any one of the first to fourth aspects, an insulating coating is formed on the surface of the metal fitting buried in the cement material.

According to the invention of claim 6, the invention of claims 1 to 5
In the invention described in any one of claims, the conductive insulator
Is a rod-shaped conductive insulator.

According to the invention of claim 7, the invention according to claim 6
Surface resistance of the first and second conductive layers
10 to 30 MΩ, and the surface resistivity of the sand part is 0.5
~ 3 MΩ, the surface resistivity of the conductive coating is 10 KΩ or less
Is set to.

[0020] In the invention described in claim 8, to claim 1
The invention according to claim 7, wherein the metal fitting
Has an end closing structure and corresponds to the closing end of the metal fitting.
An insulator layer is provided on the surface of the insulator body.

According to a ninth aspect of the invention, the insulator main body and the high electric
Attached to the insulator body via a cement material with resistance.
It is a conductive insulator having a metal fitting that is exposed to the outside.
A conductive insulator with the outer surface of the insulator body coated with a conductive glaze layer.
In the above, the conductive insulator is a suspended insulator,
The insulator body has a head and a recess inside the head.
And the metal cap is attached around the head
Pin fittings that are attached to the tool and the recess.
Insulation on at least part of the surface of the insulator
A glaze layer is provided and sand is applied on the insulating glaze layer.
Particles are provided, and the lower part of the outer peripheral surface of the insulator body and the head part
A conductive particle layer is provided below the inner peripheral surface, and the insulating glaze layer and
And softer than the insulating glaze layer coating the conductive particle layer
A kana conductive film is formed, and the conductive film is formed of the conductive particles.
It is electrically connected to the child layer and the conductive glaze layer.

According to the invention of claim 10, in claim 9,
In the invention described above, the head has a cylindrical shape,
The inner circumference of the lower end of the metal fitting extends almost parallel to the outer circumference of the insulator body.
Forming a straight portion that opposes the straight portion
A conductive particle layer is formed on the surface of an insulator body.

In the invention of claim 11, claim 9 or the contract
In the invention of claim 10, the surface of the conductive glaze layer
The surface resistivity of the conductive coating is smaller than the resistivity.
It

According to a twelfth aspect of the present invention, in the invention according to the ninth or tenth aspect, the surface resistivity of the conductive glaze layer is 15 to 50 MΩ and the surface resistivity of the conductive particle layer is 0.5 to 3 MΩ. , The surface resistivity of the conductive coating is 10K
It is set to Ω or less. In the invention according to claim 13, a second conductive layer is provided on at least a part of the surface of the insulator body buried in the cement material, and the surface of the insulating sand particles is electrically conductive on the second conductive layer. Is provided with a sand layer having a coating layer formed thereon, and a conductive coating film softer than the second conductive layer and the second conductive layer coating the sand portion is formed. It is electrically connected to the first conductive layer.

[0025]

[0026]

[Operation / Effect] By forming a conductive coating film that is softer than the second conductive layer on the second conductive layer, the cement material having high electrical resistance is subjected to contraction stress and mechanical stress. It is possible to reduce the concentration of the conductive layer and the sand portion buried in. Furthermore, it is possible to prevent minute gaps between the two due to the gap between the conductive glaze layer on the insulator surface due to the drying shrinkage of Portland cement, to secure electrical continuity between them, and to prevent the occurrence of corona discharge. it can.

In addition to the features of the present invention described above, the combination of the following features is a preferred embodiment of the conductive insulator of the present invention. Unless there is a contradiction, the following (1)
Conductive insulators obtained by arbitrarily combining the features of (15) to (15) are also mentioned as preferred embodiments of the present invention.

(1) A sand portion is provided on the second conductive layer, and the second conductive layer and the sand portion are covered with the conductive coating. By doing so, the tensile stress acting between the insulator body and the metal fitting is reliably received by the sand portion, and as a result, the mechanical strength of the conductive insulator is improved.

(2) The sand portion is composed of sand particles, and the sand particles are coated with a conductive coating. By doing so, the conductivity of the surface of the insulator main body buried in the cement material is continuously ensured, so that the conductivity of the entire conductive insulator is further improved.

(3) The second conductive layer is provided at least in the vicinity of the surface portion where the cement material is exposed to the outside. Water droplets, dirt, etc. are likely to adhere to the places where the cement material is exposed to the outside, and an electric current easily flows between the conductive layer on the insulator body and the metal fitting through the water droplets, dirt, etc. As a result, the conductive layer at this location is easily damaged, but by providing the second conductive layer at least in the vicinity of the surface portion where the cement material is exposed to the outside, the conductive layer becomes the second conductive film. The protective layer prevents the conductive layer from being damaged.

(4) The second conductive layer is provided on at least substantially the entire side surface of the insulator body buried in the cement material. By doing so, conduction between the insulator main body and the metal fitting is performed at least through substantially the entire side surface of the insulator main body buried in the cement material, so that the conductivity of the entire conductive insulator is further improved.

(5) The conductive coating has alkali resistance. Since the cement material contains alkali ions, it is possible to improve the durability of the conductive coating, by extension, the conductive layer, and the conductive insulator by imparting alkali resistance to the conductive coating.

(6) An insulating coating is formed on the surface of the metal fitting buried in the cement material. By doing so, it is possible to prevent the generation of rust due to the chemical reaction between the surface of the metal fitting and the cement during curing of the cement, and to prevent deterioration of the metal fitting. The thickness of the insulating coating is preferably 20 μm or less, as will be described later. By doing so, conduction due to electrostatic coupling of the insulating film can be improved.

(7) Table of insulator body buried in cement material
An insulating glaze layer is provided on at least a part of the surface, and
A conductive particle layer made of sand particles is provided on the insulating glaze layer.
Coating the insulating glaze layer and the conductive particle layer
Form a conductive coating that is softer than the insulating glaze layer
Conductive film is electrically connected to the conductive particle layer and the conductive glaze layer.
ing. By doing this, the insulating glaze layer is
Since the coefficient of thermal expansion is smaller than that of the child body, the insulating glaze layer
It is possible to apply compressive stress to the insulator body surface,
It is possible to maintain a predetermined strength. It will be described later
The thermal expansion coefficient of the insulating layer is better than the thermal expansion coefficient of the insulator body.
Is preferably 0.1 to 0.15% smaller. In addition,
While maintaining the strength of the insulator by the edge glaze layer, the conductive coating
Therefore, the conductivity can be further improved. Further, the insulator main body is provided with a head and a recess, and the metal fittings are a cap metal fitting attached around the head and a pin metal fitting attached to the recess. The present invention is advantageously adapted to conductive insulators such as suspended insulators having such a structure.

[0035]

[0036]

( 8 ) The head portion has a cylindrical shape, and a strut portion extending substantially parallel to the outer circumference of the insulator body is formed on the inner circumference of the lower end portion of the cap fitting, and the insulator body faces the strut portion. A conductive particle layer is formed on the surface of the. With this configuration, the current density in the portion of the metal fitting near the cement surface where current concentration is likely to occur can be reduced, and the occurrence of corona discharge can be effectively prevented. Furthermore, since the straight portion of the cap fitting extends parallel to the cylindrical surface of the insulator body, so the load of the insulator is not applied to the conductive glaze layer, it is possible to avoid a reduction in the mechanical strength of the insulator, insulator Can maintain strength. As will be described later, it is preferable that the conductive particle layer is also formed on the boundary surface between the inner peripheral surface of the insulator body and the cement material. By doing so, the electric field in the portion where current concentration is likely to occur is relaxed, and the occurrence of corona discharge can be prevented.

( 9 ) From the surface resistivity of the conductive glaze layer ,
Set the surface resistivity of the conductive coating small. With this configuration, the current that has entered the conductive film diffuses and spreads inside the conductive film faster than it spreads in the conductive layer.
The current concentration can be further reduced and the electric field between the metal fitting and the conductive coating can be further relaxed. As a result, the electrical conductivity between the conductive glaze layer and the metal fitting on the insulator body can be further improved.

( 10 ) The surface resistivity of the first and second conductive layers is 15 to 50 MΩ, the surface resistivity of the conductive particle layer is 0.5 to 3 MΩ, and the surface resistivity of the conductive coating is Is 10 kΩ or less. With such a configuration, due to the action described in ( 8 ), current concentration and current density reduction in the vicinity of the cement surface and corona discharge prevention can be more effectively achieved.

( 11 ) The conductive insulator is a rod-shaped conductive insulator. The present invention is suitable for a conductive insulator such as a rod-shaped insulator having such a structure. Here, the rod-shaped insulator refers to a station post, a line post, a long-walled insulator or the like.

( 12 ) In the rod-shaped insulator, the surface resistivity of the first and second conductive layers is 10 to 30 MΩ, the surface resistivity of the sand part is 0.5 to 3 MΩ, and the conductive coating film has a surface resistivity of 0.5 to 3 MΩ. The surface resistivity is 10 KΩ or less. With this configuration, the action and effect described in ( 9 ) above can be effectively achieved in the rod-shaped insulator.

( 13 ) The metal fitting has an end closing structure,
An insulating layer is provided on the end surface of the insulator body corresponding to the closed end of the metal fitting. When the surface of the insulator main body corresponding to the closed end of the metal fitting is coated with a conductive coating, the metal fitting and the conductive surface of the insulator main body rub against each other at the time of assembly to break the insulating coating on the surface of the metal fitting. In such a case, a battery action occurs between the conductive substance in the conductive coating and the surface of the metal fitting, which causes rusting of the metal fitting. Such a situation can be avoided by providing an insulating layer on the end surface of the insulator corresponding to the closed end of the metal fitting. Instead of the insulating layer, an insulating member may be arranged between the closed end of the metal fitting and the corresponding end surface of the insulator body.

[0043]

[Embodiment] Hereinafter, a first embodiment in which the conductive insulator of the present invention is embodied as a full-surface conductive station post insulator will be described with reference to FIGS. 1 to 6 by taking the base portion of the insulator as an example. In addition, this insulator is hereinafter referred to as a conductive insulator.

On the outer peripheral surface of the cylindrical insulator body 1 made of porcelain, a plurality of ring-shaped cap portions (not shown) are integrally formed. Metal fittings 2 are attached to both ends of the insulator body 1 to form a conductive insulator as a whole.

On the peripheral surface of the insulator body 1 excluding both end surfaces,
A conductive glaze layer 3 is applied over the entire surface. Also,
A large number of conductive glaze particles 4a are formed on the outer peripheral surface of the end portion of the insulator body 1.
The sand part 4 is formed by. This conductive glaze grain 4
The symbol a is obtained by applying a conductive glaze to the outer peripheral surface of the sand particles. In this way, surface conduction of the insulator body 1 covered with the sand portion 4 and the conductive glaze layer 3 is secured.
The surface resistivity of this insulator body 1 is 30 MΩ or less, sand
The surface resistivity of the parts is set to 3 milliohms.

On the surface of the end portion of the insulator body 1 and the end surface of the insulator body 1 which are covered with the sand portion 4 and the conductive glaze layer 3, a conductive film made of soft conductive bituminous paint as a conductive film is formed. 5 is formed by coating. The conductive bituminous paint is a paint that uses a bitumen such as pitch or asphalt as a vehicle, and contains carbon in order to have conductivity.

The application of such a soft conductive coating has the purpose of alleviating the concentration of stress and mechanical stress due to the contraction of Portland cement 7 as a cement material having a high electric resistance, which will be described later, to the sand portion. Smooth the flow of current from the conductive glaze layer 3 to prevent electric field concentration,
It is applied for the purpose of preventing the deterioration of the conductive glaze layer 3. In this embodiment, the surface resistivity of the conductive coating 5 is 4 KΩ or less, and the film thickness is 25 μm or less.

The conductive glaze layer 3 is provided on at least a part of the surface of the insulator body 1 buried in the cement material 7 and the first conductive layer that covers the outer surface of the insulator body 1 exposed to the outside. It is divided into two conductive layers.

An insulating paint layer 6 made of insulating bituminous paint as an insulating coating is formed on the inside of the metal fitting 2 by spray coating. This metal fitting 2
The inner layer 6 physically shields the zinc between the surface of the metal fitting 2 and the cement 7 during curing of the cement, and prevents a chemical reaction with the cement 7. As such a bituminous paint, those known in the art can be used.

The insulating paint layer 6 needs to have a certain degree of conductivity. When the layer 6 has no pinhole in its coating, a small amount of current flows due to electrostatic coupling conduction, but a large amount of current cannot flow. It is also considered that when the film thickness is 50 μm or more, electrostatic coupling conduction is blocked and conduction cannot be established. Therefore, in order to improve the conduction performance, it is desirable that the layer 6 is less than 50 μm, as thin as possible, and has pinholes. In the present embodiment, as described above, the layer 6 is formed by spraying the insulating bituminous paint, and therefore, numerous pinholes (not shown) are formed.

In the above embodiment, the thickness of the layer 6 was about 5 μm. The metal fitting 2 is fitted and fixed to both ends of the insulator main body 1 by Portland cement 7. In addition,
The conductive paint layer 5 protrudes from the end surface of the cement 7 to the outside. This protruding length range is 0.5 to 10
mm is preferable, and 2-8 mm is more preferable. In addition, since the conductive coating and the metal fitting may come into direct contact with each other on the inner bottom surface of the metal fitting, in this case, it is desirable to interpose an insulating spacer such as hard cork or resin between them.

The conductive structure of the conductive insulator having the above structure will be described in detail. As shown in FIG. 3, the current from the metal fitting 2 for conducting free electrons is an insulating paint layer 6 (a small part is insulating film breakdown conduction) that conducts conduction by ionic current and conduction by electrostatic coupling, conduction by ionic current. It is guided to the free electron conducting sand portion 4 and the conductive glaze layer 3 through the Portland cement 7 for conducting the above and the conductive paint layer 5 for conducting by free electrons. The current from the conductive glaze layer 3 is applied in the reverse order. A conductive coating 5 is arranged between the conductive glaze layer 3 of the sand part 4 and the Portland cement 7. For this reason, most of the current flowing from the conductive glaze layer 3 and the sand portion 4 to the Portland cement 7 passes through the conductive coating, so that free electrons are conducted and the conductive performance is improved. Then, the current passes through the conductive glaze layer 3 and the other metal fitting 2
Flows between and.

Next, using the conductive insulator of this example, the relationship between the resistance of the conductive portion of the cement material and the corona discharge characteristics was investigated. The shared voltage of cement was measured with the voltage drop circuit shown in FIG. 2, and this was converted into a resistance value. In the measuring circuit, 25 is a transformer, 26 is an ammeter, and 27 is a voltmeter.

FIG. 4 shows the noise level due to corona discharge.
6 is a graph showing the relationship between the current flowing through the cement conducting portion and the resistance of the cement conducting portion in order to suppress it to 4.5 db or less. The shaded area in the figure is the area where the noise level is −4.5db or less.

As a result, as shown in the graph of FIG. 4, the maximum allowable resistance value of the cement conducting portion of the conductive insulator of this embodiment can be set to 0.3 MΩ under the actual use environment. That is, the conductive portion resistance X is expressed as X = Y / Z, where Y is the cement volume resistivity and Z is the electrode coefficient, and therefore the conductive portion resistance X = Y / Z ≦ 0.3 MΩ can be satisfied. The range of meteorological conditions can be set as the applicable range of the conductive insulator. If the insulator is operated within this range, the occurrence of corona discharge can be suppressed to a background level of about -4.5 db, and the problem due to corona discharge can be solved.

Next, the extent to which the applicable range corresponds to the actual use environment was investigated. The electrode coefficient Z in this embodiment is set as follows based on the specifications of the conductive insulator.

As shown in FIG. 2, the body diameter of the insulator body 1 is a, the body diameter of the insulator body 1 including the sand portion 4 is b, the inner diameter of the metal fitting is d, the depth of the metal fitting is f, and the maximum cement thickness at the top is g. From the above, the equivalent diameter of the insulator body 1 is c = (a + b) /
2. The equivalent inner diameter of the metal fitting is expressed as e = d + 3, and the side cement portion electrode facing depth h = f−g.

The side electrode facing area i is i = π
It is expressed as ((c + e) / 2) h. From the above, the facing area of the electrodes on the side surface is S1 = i, and the distance between the electrodes is L1 = (e
-C) / 2, and the electrode coefficient on the side surface is j = S1 / L1 =
i / ((ec) / 2). The counter area S2 = πc ^2/4 electrodes in the end faces, the distance between the electrodes L2 = g
And the electrode coefficient of the end face is k = S2 / L2 = (πc ² /
4) / g. Therefore, the electrode coefficient of this conductive insulator is Z
= J + k.

FIG. 5 shows the relationship between the volume resistivity of Portland cement 7 of this example at the dry-wet equilibrium and the drying conditions.
Is shown in the graph. This was performed under conditions of absolute humidity of 7.5 g / m ³ and no rainfall simulation. And, for example, as a severe region in actual use of the present conductive insulator or the like, there is a desert region of Saudi Arabia. Meteorological conditions in this area are based on past data
Since the climate is ℃, absolute humidity 10g / m ³ and no rainfall, it is enough to add the annual average temperature rise of 20 ° C and consider the annual average drying conditions as 45 ° C and 10g / m ³ absolute humidity. is there. When this condition is applied to the graph of FIG. 5, the volume resistivity of the cement is 1 under this dry condition.
It can be seen that it is 2 MΩ · cm or less. According to this graph, 12 MΩ · cm at an absolute humidity of 7.5 g / m ³ .
Therefore, it can be seen that when the wet condition is 10 g / m ^3, it naturally becomes 12 MΩ · cm or less.

Then, the conductive insulator having the above structure is
A conductive insulator having the specifications of the table shown in FIG. 6 and used in a 69 kV class power transmission line. This 69 kV class conductive insulator has a low electrode coefficient. When this data is applied to the above-described formula for obtaining the electrode coefficient Z, the electrode coefficient Z of the cement conducting portion is 407 cm as shown in the table.
Therefore, the resistance of the conducting portion is Y / Z = 12 (MΩ · cm) / 407 (c) even under the weather conditions of Saudi Arabia.
m) = 0.06 (MΩ) = X <0.3 (MΩ).
Then, from the above-mentioned test, the conductive insulator of this example has X =
It can be seen that the occurrence of corona discharge can be suppressed if Y / Z ≦ 0.3.

In other words, the desert area of Saudi Arabia, which is a severely used area for insulators, has a low electrode coefficient.
It can be seen that the conductive station post insulator for 9 kv class is within the applicable range. In other words, in the conductive insulator of this example, the conductive sand portion 4 is used.
The surface of the porcelain insulator 1 covered with the conductive glaze layer 3 was conductively coated with a conductive bituminous paint layer 5. Therefore, the conductive performance of the cement conducting portion can be improved, and the conducting method using the Portland cement material can be actually used.

Since the other metal fitting and the insulator body 1 are connected to each other in the same manner as in the present embodiment, there is no problem of corona discharge occurring under the same use environment. Next, a second embodiment in which the conductive insulator of the present invention is embodied as a whole surface conductive suspension type insulator (hereinafter, referred to as a conductive insulator) will be described in detail with reference to FIGS. 7 and 8.

As shown in FIG. 8, the insulating glaze layer 15a is
Cement material 1 on the surface of the insulator main body 10 by the insulating glaze
It is formed in the part buried in 8. Sand particles 12
Is provided on the insulating glaze layer 15a in the cylindrical head portion 10c of the insulator body 10. Conductive paint layer 13
Is formed on the sand particles 12 or the insulating glaze layer 15 a and is electrically connected to the conductive particle layer 21 and the conductive glaze layer 11.

A straight portion 20 is formed on the inner peripheral surface of the lower end portion of the cap metal fitting 14 so as to extend substantially parallel to the head portion 10c of the insulator main body 10, and the most load is applied to the surface of the head portion 10c. It extends from the joining position to near the end face of the metal fitting. The conductive glaze layer 11 is formed on the surface of the insulator body 10 from the cap portion 10a to the straight portion 2 of the cap fitting 14.
The coating is formed over the portion facing 0.
The conductive glaze layer 11 on the insulator body has a surface resistivity of 20 MΩ.

The conductive particle layer 21 is provided on the lower end portion of the outer peripheral surface of the head of the insulator main body 10 by the straight portion 20 of the cap fitting 14.
The coating is formed so as to correspond to. The surface resistivity of this layer 21 is 0.5 to 3 MΩ, and the conductivity is good. Therefore, the conductive particle layer 21 relaxes the electric field in the portion where the current is likely to concentrate, and suppresses the occurrence of corona discharge in this portion. The insulating coating layer 15 is the cap fitting 1
4 is formed on the inner peripheral surface.

On the other hand, the insulating glaze layer 15a, the sand particles 12, and the conductive paint layer 13 are provided on the inner peripheral surface of the head 10c of the insulator body 10, and the conductive particle layer is formed below the inner peripheral surface of the head 10c. 21 is provided.

The conductive structure of the conductive insulator having the above structure will be described in detail. As shown in FIG. 7, for example, a current from a pin metal fitting of an upper insulator is generated by a cap metal fitting 14 of free electron conduction,
Insulating paint layer 1 for ionic current conduction and electrostatic coupling conduction
5 (a small part of insulating film breakdown conduction), ionic current conduction cement material 16 and free electron conduction conductive paint layer 13
To the conductive particle layer 21 with free electron conduction.
The insulative paint layer 15 is insulative, but current can flow by ionic conduction and electrostatic coupling conduction through a myriad of pinholes. In this example, no corona is observed even at a current of 1 mA. The current flowing through the cement material in the normal use condition is 0.
It is about 6 mA.

Then, from the conductive particle layer 21, the conductive glaze layer 11, the conductive particle layer 21, and the conductive paint layer 1 are further formed.
3, through the cement material 18 and the insulating paint layer 15 to reach the pin fitting 17 for free electron conduction, and flow into the cap fitting 14 of the lower insulator, for example. In addition, the current flowing from the cap member 14 of the lower insulator is flown to the pin member 17 of the upper insulator by the reverse path.

Incidentally, the conductive particle layer 21 and the cement material 16
By disposing the conductive paint layer 13 between
Free electrons are conducted from the conductive particle layer 21, and the conductive performance of the conductive portion of the conductive particle layer 21 is improved.

Further, the sand particles 12 may be conductive sand portions (conductive glaze particles) as shown in FIGS. And also in the conductive insulator of the present embodiment,
The resistance of the cement conducting portion can be treated in the same manner as in the first embodiment. Therefore, the applicable range is X =
It is a range satisfying Y / Z ≦ 0.3 MΩ. The electrode coefficient in this embodiment is the head 10c embedded in the cement material 16.
The surface area of S1, the inner peripheral surface of the cap fitting 14 and the head 10
When the equivalent distance between c is L1, the electrode coefficient on the side of the cap fitting 14 is Z1 = S1 / L1. If the surface area of the pin metal fitting 17 buried in the cement material 18 is S2 and the equivalent distance between the pin metal fitting 17 and the pin housing recess 10d is L2, the electrode coefficient on the side of the pin metal fitting 17 is Z2 = S2 / L2.

The electrode coefficient Z of the conductive insulator of this embodiment is determined by the smaller coefficient of Z1 and Z2, and the electrode coefficient Z2 of the pin fitting 17 is usually smaller. That is, the conductive insulator of the present embodiment can withstand actual use by being applied to a suspended insulator having specifications having an electrode coefficient Z that can satisfy X = Y / Z ≦ 0.3 MΩ. It will be possible.

Now, in this embodiment, the cap fitting 14
The straight portion 20 was provided on the inner periphery of the lower end portion of the above, and the conductive particle layer 21 having good conductivity was provided on the outer peripheral surface and the inner peripheral surface of the insulator body 10 facing the straight portion 20. Therefore, it is possible to reduce the current density in the vicinity of the metal fittings 14 and 17 where current concentration is likely to occur.
The occurrence of corona discharge can be effectively prevented. Moreover, since the maximum load of the insulator is not applied to the conductive particle layer 21 by the straight portion 20 of the cap fitting 14,
The mechanical strength of the insulator can be prevented from lowering, and the strength of the insulator can be maintained.

By the way, in the suspended insulator, since the insulator body 10 is made of alumina porcelain, the coefficient of thermal expansion of the insulator body at 650 ° C. and the coefficient of thermal expansion of the conductive glazed layer formed on the peripheral surface thereof. Is smaller than the range of 0.1 to 0.15%. Therefore, it is impossible to apply a compressive stress due to the conductive glaze layer to the surface of the insulator body by utilizing the difference in the coefficient of thermal expansion. However, in this embodiment, the difference between the thermal expansion coefficient of the insulating glaze layer 15a and the insulator body is set on the peripheral surface of the head 10c of the insulator body 10 in the range of 0.1 to 0.15%, and the insulation A predetermined compressive stress is obtained by the glaze layer 15a, and the insulator strength can be maintained at a required strength.

Since the conductive paint layer 13 and the conductive particle layer 21 are provided in the conductive mechanism, even if the conductive paint layer 13 is deteriorated with time, the conductive particle layer 21 is sufficient. Can be conducted to. Further, in the suspended insulator, even if the cap portion 10a is broken, the portion of the head portion 10c remains integrally with the cap fitting 14 and the pin fitting 17, so that the reliability of the insulator can be secured.

Next, a third embodiment in which the present invention is embodied in a station post insulator made of a rod-shaped insulator will be described in detail with reference to FIG. As shown in FIG. 9, the conductive glaze layer 3 is formed on the peripheral surface of the insulator body 1 and has a surface resistivity of 20 MΩ. The insulating sand particles 4b are provided on the conductive glaze layer 3. The coating layer 8 is insulating
Is formed on the surface of the sand particles 4b, and has a surface resistivity of 0.5 to 3 MΩ. The conductive paint layer 5 is formed on the surface of the sand portion 4 having the coating layer 8 with a conductive bituminous paint and has a surface resistivity of 10 KΩ or less. On the other hand, the insulating paint layer 6 is provided on the inner peripheral surface of the metal fitting 2.

In this embodiment, the conductive glaze layer 3 is provided on the entire peripheral surface of the porcelain insulator body 1.
The coefficient of thermal expansion at 0 ° C is 0.1 to 0.15% higher than the coefficient of thermal expansion of the cristobalite-based substrate forming the insulator body 1.
Only small. Therefore, a compressive stress due to the conductive glaze layer 3 is applied to the insulator body 1 based on the difference in the coefficient of thermal expansion,
The strength of the insulator body 1 can be maintained. Moreover, the conductive glaze layer 3, the coating layer 8 on the surface of the sand particles 4b, and the conductive paint layer 5 ensure a current conduction path. As a result, generation of corona discharge due to current concentration can be prevented.

Next, a fourth embodiment in which the present invention is embodied in a station post insulator made of a rod-shaped insulator will be described with reference to FIG. In this embodiment, only parts different from the first embodiment will be described.

As shown in FIG. 10, the insulating glaze layer 6a
Is formed on the bottom (or top) of the insulator main body 1 by insulating bituminous paint, and the end thereof covers the end of the conductive paint layer 5 provided on the peripheral surface of the insulator main body 1. Therefore, the conductive paint layer 5 is not provided on the bottom of the insulator body 1.

In this embodiment, the insulating glaze layer 6a is provided on the bottom surface of the insulator body 1. Therefore, at the bottom of the insulator main body 1, it is possible to prevent the metal contained in the conductive paint layer 5 from coming into contact with the metal fitting 2 to cause electrolytic corrosion to corrode the metal fitting 2. Although an insulating paint layer 6 is provided on the inner surface of the metal fitting 2, a large number of pinholes are present in this layer 6. Therefore, electrical connection between the metal fitting 2 and the conductive paint layer 5 on the surface of the insulator body 1 is possible.

The present invention can be embodied with the following modifications, for example. (A) The present invention is applied to a line post insulator or the like provided on a steel tower and supporting a power transmission line. (B) In the second embodiment, instead of the conductive particle layer 21, the conductive glaze layer 11 is formed extending to that portion.

Further, the technical idea understood from the above embodiment will be described below. (1) The conductive insulator according to claim 1, wherein the conductive coating protrudes from the end surface of the cement. According to this structure, the conduction of the cement conductive portion by the conductive coating can be surely performed. (2) The difference in coefficient of thermal expansion between the insulating layer and the insulator body is 0.1 to 0.1%.
The conductive insulator according to claim 9 , which is set in a range of 0.15%. With this configuration, the strength of the insulator body can be maintained. (3) The conductive insulator according to claim 9 , wherein a conductive particle layer is formed on a boundary portion between the inner peripheral surface of the insulator body and the cement material. According to this structure, it is possible to secure the continuity of the portion where current concentration is likely to occur and prevent the occurrence of corona discharge.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a base portion of a station post insulator according to a first embodiment.

FIG. 2 is an explanatory diagram showing various specifications for setting an electrode coefficient.

FIG. 3 is a block diagram showing a conductive structure of the present embodiment.

FIG. 4 is a graph showing the relationship between the resistance of the cement conducting portion and the corona characteristics.

FIG. 5 is a graph showing the relationship between the volume resistivity of cement and temperature.

FIG. 6 is an explanatory diagram showing the specifications of a 69 kv class station post insulator.

FIG. 7 is a block diagram showing a conductive structure of a second embodiment .

FIG. 8 is a partially enlarged cross-sectional view showing a suspended insulator of the second embodiment.

FIG. 9 is a partially enlarged sectional view showing a station post insulator according to a third embodiment.

FIG. 10 is a partially enlarged sectional view showing a rod-shaped insulator according to a fourth embodiment.

FIG. 11 is a sectional partial view showing a conductive insulator by a conventional metal spraying method.

FIG. 12 is a sectional partial view showing a conductive insulator by a conventional metal connection method.

[Explanation of symbols]

1, 10 ... Insulator main body, 2 ... Metal fittings, 3 , 11 ... Conductive glaze layer as first conductive layer and second conductive layer, 4 ... Sand part, 5 , 13 ... Conductive paint layer as conductive coating ,
6 ... Insulating paint layer as insulating coating, 7 ... Cement material having high electric resistance , 14 ... Cap metal fitting, 15a
... Insulating glaze layer as insulating layer, 17 ... Pin fitting, 20 ...
Straight part, 21 ... Conductive particle layer.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiji Kumina No. 2-56 Sudamachi, Mizuho-ku, Nagoya City Insulator of Japan Incorporated (56) Reference JP 49-96288 (JP, A) JP 53 -146197 (JP, A) JP-B 34-2785 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01B 17/00-17/66

Claims (13)

(57) [Claims] 1. A conductive insulator having an insulator main body and a metal fitting attached to the insulator main body via a cement material having high electric resistance, wherein the outer surface of the insulator main body exposed to the outside is a first conductive layer. In a conductive insulator coated with, a second conductive layer is provided on at least a part of the surface of the insulator body buried in the cement material, and a sand portion made of conductive sand particles is provided on the second conductive layer. A conductive coating that is provided and is softer than the second conductive layer that coats the second conductive layer and the sand portion, and the second conductive layer is conductive with the first conductive layer. A porcelain insulator. 2. The conductive insulator according to claim 1, wherein the second conductive layer is provided at least in the vicinity of a surface portion where the cement material is exposed to the outside. 3. The conductive insulator according to claim 1, wherein the second conductive layer is provided on at least an outer peripheral surface of a cylindrical insulator body buried in the cement material. 4. The conductive insulator according to claim 1, wherein the conductive coating has alkali resistance. 5. The conductive insulator according to claim 1, wherein an insulating coating is formed on the surface of the metal fitting buried in the cement material. 6. The conductive insulator is a rod-shaped conductive insulator.
A conductive insulator according to any one of claims 1 to 5.
Child. 7. The surface resistance of the first and second conductive layers
The surface resistivity of the sand portion is 0.
5 to 3 MΩ, the surface resistivity of the conductive coating is 10 KΩ or less
The conductive insulator according to claim 6, which is set below. 8. The metal fitting has an end closing structure,
An insulating layer is provided on the surface of the insulator body corresponding to the closed end.
The conductive insulator according to any one of claims 1 to 7.
Child. 9. An insulator body and cement having a high electric resistance.
Conductor with metal fittings attached to the insulator body via
It is an electrical insulator and the outer surface of the insulator body exposed to the outside
A conductive insulator covered with a conductive glaze layer, wherein the conductive insulator is a suspended insulator and the insulator
The main body has a head and a recess inside the head.
Cap fittings and recesses where tools are attached around the head
A pin fitting attached to the at least the surface of the insulator body buried in the cement material.
An insulating glaze layer is provided on a part of the insulating glaze layer.
Sand particles are provided on the bottom of the outer peripheral surface of the insulator body
And a conductive particle layer under the inner peripheral surface of the head,
A glaze layer and an insulating glaze layer for coating the conductive particle layer.
Forms a softer conductive film, and the conductive film is
Conductive particle layer and conductivity that is in conduction with the conductive glaze layer
insulator. 10. The cap has a cylindrical shape, and the cap is provided.
Extends almost parallel to the outer circumference of the insulator body on the inner circumference of the lower end of the metal fitting
An insulator that forms a straight portion and faces the straight portion
The conductive particle layer is formed on the surface of the main body according to claim 9.
Conductive insulator. 11. The surface resistivity of the conductive glaze layer is used to determine the conductivity.
10. The surface resistivity of the electrically conductive coating is low, or claim 9 or claim 1.
0, the conductive insulator. 12. The surface resistivity of the conductive glaze layer is 15 to 15.
50 MΩ, the surface resistivity of the conductive particle layer is 0.5 to 3 M
Ω, the surface resistivity of the conductive coating is set to 10 KΩ or less
11. The conductive insulator according to claim 9 or 10. 13. A conductive insulator having an insulator body and a metal fitting attached to the insulator body via a cement material having a high electric resistance, wherein the outer surface of the insulator body exposed to the outside is the first conductive layer. In the conductive insulator coated with, a second conductive layer is provided on at least a part of the surface of the insulator body buried in the cement material, and the surface of the insulating sand particles is electrically conductive on the second conductive layer. Is provided with a sand layer having a coating layer formed thereon, and a conductive coating film softer than the second conductive layer and the second conductive layer coating the sand portion is formed. An electrically conductive insulator that is electrically connected to the first electrically conductive layer.