JPH04298919A - Electric corrosion-resistant insulator - Google Patents

Abstract

PURPOSE:To prevent the occurrence of electric corrosion on a pin metal by eliminating the current flowing into cement from the barrel section of the pin metal. CONSTITUTION:A conducting layer 13 with the resistance value smaller than that of cement 9 is provided on the surface layer section of the cement 9 for burying and fixing a pin metal 8 in an insulator main body 1. An insulating layer 14 is provided at a connection section between a current feeding anode 11 provided at the middle section of the pin metal 8 and the conducting layer 13 to prevent the electron conduction in the connection section.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an electrically corrosion resistant insulator.

0002

2. Description of the Related Art Conventionally, in DC transmission lines or polluted areas, in order to prevent electrical corrosion of pin fittings due to leakage current and damage to insulators caused by this, intermediate portions of pin fittings 8 are used as shown in FIG. An electrolytic corrosion-resistant insulator provided with a galvanic anode 11 is used. This galvanic anode 11 is provided protruding from the outer periphery of the pin fitting 8 so as to be located at the boundary between the pin fitting 8 and the cement 9, and a portion thereof is embedded in the cement 9.

In this electrolytic corrosion-resistant insulator, if the entire cement 9 in which the pin fitting 8 is embedded becomes wet under a severely contaminated environment, and only the surface of the cement 9 dries and becomes semi-dry, the insulator body 1 and the pin The resistance value between the body of the metal fitting 8 becomes the minimum value, and a current flows into the cement 9 from the body of the pin metal fitting 8 embedded in the cement 9. That is, when the leakage current from the outside is I, the resistance on the surface of the cement 9 is R1, and the internal resistance of the cement 9 is R2, the current i1 flowing from the body of the pin fitting 8 into the cement 9 is:
The flow is inversely proportional to the resistances R1 and R2, as shown in equation (1) below.

0004

[Math. 1] i1={R1÷(R1+R2)}×I...(
1) At this time, since the suppressing current i2 is flowing from the current anode 11 due to the action of the oxygen concentration cell, the actual current i0 flowing out from the body of the pin fitting 8 is as shown in equation (2).

[0005]

[Equation 2]i0=i1-i2...(2) Also, the leakage current i3 flowing on the cement surface is expressed by equation (3).

[0006]

[Math. 3] i3={R2÷(R1+R2)}×I...(3)

[0007]

[Problems to be Solved by the Invention] Therefore, in this conventionally configured electrolytic corrosion resistant insulator, the pin fitting 8 undergoes electrolytic corrosion due to the current flowing from the body of the pin fitting 8 into the cement 9. There has been a problem in that the rust generated during this process generates a large internal pressure stress inside the insulator, which can cause the insulator to break.

[0008] The present invention was made by focusing on the problems existing in the conventional technology, and its purpose is to prevent the current flowing from the body of the pin fitting into the cement. An object of the present invention is to provide an electrolytic corrosion-resistant insulator that can prevent electrolytic corrosion of pin fittings and prevent destruction of the insulator.

[0009]

[Means for Solving the Problems] In order to achieve the above object, in this invention, the insulator body is filled with cement,
Embed and fix the pin fittings in the cement at the upper end,
A galvanic corrosion-resistant insulator is provided with a galvanic anode partially embedded in the cement in the middle part of the pin fitting, and a conductive layer with a resistance value smaller than that of the cement is provided in the surface layer of the cement. Insulation is provided between the junction between the conductive layer and the galvanic anode.

0010

[Function] In the electrolytic corrosion-resistant insulator constructed as described above, a conductive layer with a resistance value lower than that of the cement is provided on the surface layer of the cement, so current flows from the galvanic anode to the conductive layer on the surface layer of the cement. Since the insulating layer is a thin film, the leakage current is caused by ionic conduction at the end face of the insulating layer, and the leakage current flows out dominantly.The current flowing from the body of the pin fitting into the cement is reduced, and the suppressing current i2 is smaller than the pin fitting. The current i1 flowing from the body into the cement becomes smaller. This prevents electrical corrosion from occurring on the pin fittings. In addition, insulation is provided between the joint between the conductive layer and the galvanic anode, resulting in a structure that does not have electronic conduction, so when wet, there is a potential difference between the joint between the conductive layer and the galvanic anode, that is, a dissimilarity. No battery reactions occur due to the material.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electrolytic corrosion-resistant suspension insulator embodying the present invention will be described in detail below with reference to the drawings. Figure 1
As shown in FIG. 2, the insulator body 1 of the suspended insulator is integrally formed of porcelain, and includes a cylindrical head 2 with a bottom, a cap 3 formed on the outer periphery of the head 2, and a cap 3 formed on the outer periphery of the head 2. 3 and a plurality of folds 4 formed concentrically on the inner surface thereof. The cap fitting 5 is fitted and fixed to the head 2 of the insulator body 1 via a cement 6, and a fitting recess 7 is formed at the top thereof.

The pin fitting 8 is embedded and fixed in the cement 9 at its upper end with the head 2 of the insulator body 1 filled with cement 9, and a fitting part 10 is formed at its lower end. . By engaging the fitting portion 10 of this pin fitting 8 with the fitting recess 7 on the cap fitting 5 of another suspension insulator, a plurality of suspension insulators can be connected in series in the vertical direction.

The galvanic anode 11 is formed as a bulge in the middle part of the pin fitting 8 by any joining method such as casting or brazing, and a tapered part 12 is provided on the outer periphery of the upper end thereof. A portion of the tapered portion 12 of the galvanic anode 11 is embedded in the cement 9 filled in the head 2 of the insulator body 1. The conductive layer 13 is provided on the surface layer of the cement 9 in the head 2, and is prevented from falling off downward by the tapered portion 12 of the galvanic anode 11. This conductive layer 13 is made of, for example, ordinary cement with whiskers (ZnO, S
It is made of a low-resistance material made conductive by adding a conductive substance such as iO or metal, and its volume resistivity when wet is 1KΩ, which is smaller than the 15KΩ-cm of the cement part 9. -cm or less.

The insulating layer 14 is provided between the joint between the conductive layer 13 and the galvanic anode 11, and the thickness of the insulating layer 14 is 1/10 or less of the cement surface length. This insulating layer 14 insulates the junction between the conductive layer 13 and the galvanic anode 11 so that there is no electronic conduction, and a potential difference between the junction between the conductive layer 13 and the galvanic anode 11 occurs when wet. It is designed not to occur.

Next, the operation of the electrolytic corrosion resistant insulator constructed as described above will be explained. Now, in the electrolytic corrosion-resistant insulator of this embodiment, a conductive layer 13 is provided on the surface layer of the cement 9 in which the pin fitting 8 is embedded, and the volume resistivity value of the conductive layer 13 when wet is determined by the volume resistivity inside the cement 9. It is set to be 1/15 or less of the specific resistance value. Therefore, even if the inside of the cement 9 becomes wet and only the surface becomes dry, the leakage current i3 flowing from the galvanic anode 11 to the conductive layer 13 becomes dominant, and the body of the pin fitting 8 Since the current i1 flowing into the cement 9 from the part can be made smaller than the suppressing current i2, the pin fitting 8
No current flows into the cement 9 from the body. Therefore, electrolytic corrosion of the pin fittings 8 can be prevented and destruction of the insulator body 1 can be prevented.

In the electrolytic corrosion-resistant insulator of this embodiment, an insulating layer 4 is provided between the joint between the conductive layer 13 and the galvanic anode 11. Since they are not in contact with each other, no electronic conduction occurs between the conductive layer 13 and the galvanic anode 11. Therefore, it is possible to reliably prevent a potential difference from occurring between the junction between the conductive layer 13 and the galvanic anode 11 when wet.

[0017]

[Another Embodiment] Next, another embodiment of the present invention will be described based on FIGS. 3 and 4. First, in the embodiment shown in FIG. 3, an insulating layer 14 is formed on the surface layer of the cement 9 in which the pin fitting 8 is embedded and on the outer periphery of the galvanic anode 11. A conductive layer 13 is formed under the insulating layer 14 by loading a conductive rubber packing or filling with conductive silicone rubber, conductive resin, or the like.

Furthermore, in the embodiment shown in FIG.
By embedding and fixing a pair of annular conductive metal fittings 15 having a substantially H-shaped cross section with a portion thereof exposed,
A conductive layer 13 is formed on the surface layer of the cement 9. Further, a predetermined gap 16 is formed between the conductive metal fitting 15 and the outer periphery of the galvanic anode 11, thereby ensuring a structure in which there is no electronic conduction between the joint between the conductive layer 13 and the galvanic anode 11. has been done.

It should be noted that the present invention is not limited to the configuration of the above embodiment, and for example, the conductive layer 13 and the insulating layer 1
It is also possible to change the structure of each part arbitrarily and embody it without departing from the spirit of the present invention, such as changing the material and forming position of 4 as appropriate.

[0020]

[Effects of the Invention] Since the present invention is constructed as described above, it is possible to suppress the current flowing from the body of the pin fitting into the cement and prevent electrolytic corrosion from occurring in the pin fitting. This has the excellent effect of preventing the insulator from being destroyed by rust caused by electrolytic corrosion.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts of an embodiment of an electrolytic corrosion-resistant insulator embodying the present invention.

FIG. 2 is a partially cross-sectional front view of the entire electrical corrosion-resistant insulator.

FIG. 3 is a partial cross-sectional view of an electrolytic corrosion-resistant insulator showing another embodiment of the present invention.

FIG. 4 is a partial cross-sectional view showing still another embodiment of the invention.

FIG. 5 is a partial cross-sectional view showing a conventional electrolytic corrosion resistant insulator.

[Explanation of symbols]

1 insulator body, 8 pin fittings, 9 cement, 1
1 galvanic anode, 13 conductive layer, 14 insulating layer.

Claims (1)

[Claims] Claim 1: Cement is filled into the insulator body, a pin fitting is embedded and fixed in the cement at the upper end, and a galvanic anode is placed in the middle part of the pin fitting so that a part of it is embedded in the cement. In the electrolytic corrosion-resistant insulator provided in the above, a conductive layer having a resistance value lower than that of the cement is provided on the surface layer of the cement, and insulation is provided between the joint between the conductive layer and the galvanic anode. Electrolytic corrosion resistant insulator.