JP2017016910A - Conductor connection part for power cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a satisfactory electrification property while preventing oxidation on a surface of an aluminum conductor in a conductor connection part for a power cable in which at least any one of connection conductors to be electrically connected with each other is the aluminum conductor.SOLUTION: In the conductor connection part for the power cable, a connection interface between an inner peripheral surface of a cylindrical part 21 of a stationary terminal 20 and an outer peripheral surface of a connection part 11 of a conductor lead-out rod 10 and a connection interface between one surface of a tabular connection part 23 of the stationary terminal 20 and one surface of a connection conductor plate 30 are connected by being filled with a compound C consisting of a base oil, a thickener, an additive and metal particles of which the particle diameter is 100 μm or less. The inner peripheral surface of the cylindrical part and the outer peripheral surface of the connection part of the conductor lead-out rod are crimped and connected by a fastening force of a bolt 41. The one surface of the tabular connection part and the one surface of the connection conductor plate are crimped and connected by a fastening force of a bolt 42.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a conductor connecting portion of a power cable.

Aluminum immediately oxidizes upon contact with the atmosphere, forming an aluminum oxide film on the surface. Since the oxide film generates a large contact resistance at the conductor connection portion, the conductor polishing and compound coating operations are usually performed on the connection portion of the aluminum conductor before the connection. Patent Documents 1 and 2 describe conducting a conductor polishing and a compound coating operation on a connection portion of an aluminum conductor.
Patent Document 2 describes that a base oil (petroleum-based lubricant), a thickener (Al soap), carbon random particles (silicon carbide), and an additive (sulfonate) are used as a compound. Yes.

JP-A-9-161890 JP 11-232934 A

According to the inventor's research, when the compound described in Patent Document 2 is applied to a bolt tightening connection portion (a portion to be connected by a bolt tightening force), a current-carrying characteristic is insufficient. The bolt tightening connection part in the power cable connects the tip part of the aluminum conductor lead bar and the fixed terminal for connecting the overhead wire, the fixed terminal and the terminal on the overhead line side, etc. It is comprised in the flat-plate-shaped connection part, and is the result of applying the compound of patent document 2 about these connection parts.
Silicon carbide contained in the compound described in Patent Document 2 has hardness next to diamond and boron carbide, and when applied to a compression connection portion, the gap between the aluminum stranded wires is caused by a compressive force enough to deform the aluminum base material. Bite into. This produces an effect of increasing the friction of the connecting portion. However, when applied to a bolt tightening connection, it was considered that silicon carbide was scattered in the gaps, and metal contacts most important for electrical conduction could not be taken.

  The present invention has been made in view of the problems in the prior art described above, and in the conductor connection portion of the power cable in which at least one of the connection conductors electrically connected to each other is an aluminum conductor, the surface of the aluminum conductor is formed. An object is to obtain good current-carrying characteristics while preventing oxidation.

  According to a first aspect of the present invention for solving the above-described problems, in the conductor connection portion in which at least one of the two connection conductors electrically connected to each other for electrically connecting the power cable is an aluminum conductor. A conductor connection part of a power cable, wherein the connection interface is filled and connected with a base oil, a thickener, an additive, and a compound composed of metal particles having a particle size of 100 μm or less.

  The invention according to claim 2 is the conductor connection portion of the power cable according to claim 1, wherein both of the two connection conductors are aluminum conductors.

  According to a third aspect of the present invention, the two connection conductors are a conductor lead bar of a terminal connection portion of a power cable and a fixed terminal connected thereto, and the conductor lead bar is an aluminum conductor. It is a conductor connection part of the electric power cable of 2.

  Invention of Claim 4 is a conductor connection part of the power cable in any one of Claim 1 to Claim 3 by which the said 2 connection conductors were crimp-connected by the fastening force of the volt | bolt.

  According to the present invention, the connection interface, at least one of which is an aluminum conductor, is filled with a base oil, a thickener, an additive, and a compound composed of metal particles having a particle size of 100 μm or less, so that contact with oxygen The metal particles mediate electrical conduction and good current-carrying characteristics can be obtained while preventing the formation of an oxide film on the surface of the aluminum conductor by blocking the above.

It is a top view of the fixed terminal which comprises the conductor connection part of the electric power cable which concerns on one Embodiment of this invention, and the conductor extraction | drawer stick | rod inserted in this. It is a connection state top view of a conductor extraction rod, a fixed terminal, and a connection conductor plate which constitute a conductor connection part of a power cable concerning one embodiment of the present invention. It is a dismantling state figure of the connection part of the aluminum conductor extraction rod which concerns on a comparative example, and the mode of the compound adhesion surface is shown with a real image. It is a dismantling state figure of the flat connection part of the fixed terminal made from the aluminum conductor which concerns on a comparative example, and the mode of the compound adhesion surface is shown with a photographed image. FIG. 5 is a schematic cross-sectional view (a) of a connection portion in the case of compression connection and a schematic cross-sectional view (b) of the connection portion in the case of bolt tightening connection.

  An embodiment of the present invention will be described below with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.

First, the composition of Compound C will be described.
Base oil consists of mineral oil, and has the effect | action of the external air interruption | blocking to a connection part, and antioxidant.
As the thickener, metal (aluminum) soap, organic bentonite or the like is applied. The thickener has the effect of maintaining the oil in a semi-solid state.
A sulfonate or the like is applied as the additive. The additive has an antioxidant effect on the grease component.
The metal particles are preferably zinc particles. The metal particles have an effect of reducing the contact resistance of the connection portion. The particle size of the metal particles is 100 μm or less, and more preferably 10 μm or less. A compound to which fine zinc particles of 10 μm or less are added shows even better characteristics.
Since the metal particles bridge the electrical contact between the conductor lead bar and the connection terminal, the smaller the metal particle size, the more metal particles can contribute to the bridging, but the metal particle size exceeds 100 μm. Then, the bridging effect of the metal particles having a particle size less than the maximum particle size is hindered, resulting in poor conductivity.
Moreover, although it does not specifically limit, 1 micrometer or more is preferable. If it is less than 1 μm, it may be difficult to contribute to the electric conduction in the filled range.
Silicon carbide is not used. This is because silicon carbide improves the mechanical strength of the connection part, but inhibits the contact between metals and does not have a bridging effect for conduction.

Next, the configuration of the conductor connection portion of the power cable according to the present embodiment will be described.
As shown in FIG. 1 and FIG. 2, the conductor lead bar 10 at the terminal connection portion of the power cable is connected to the fixed terminal 20, and the fixed terminal 20 is connected to the connection conductor plate 30 such as a terminal on the overhead wire side. To do. That is, the fixed terminal is a current-carrying joint for electrically connecting the terminal end of the power cable and a counterpart (such as an overhead wire).

The fixed terminal 20 includes a cylindrical portion 21, a bolt fastening portion 22, and a flat plate-like connection portion 23.
The cylindrical portion 21 opens on one side and receives the connecting portion 11 of the conductor lead bar 10 inside. Bolt fastening portions 22 each having bolt insertion holes 22a are formed on both sides of the cylindrical portion 21. The cylindrical portion 21 and the bolt fastening portion 22 are divided on the axial surface, and the bolt 41 inserted through the bolt insertion hole 22a is screwed into the nut on the opposite side and fastened to be disposed inside the cylindrical portion 21. The cylindrical portion 21 tightens the connecting portion 11 at the tip of the conductor lead bar 10 thus formed. By the fastening force of the bolt 41, the inner peripheral surface of the cylindrical portion 21 and the outer peripheral surface of the connection portion 11 of the conductor lead bar 10 are crimped and connected.
A flat plate-like connecting portion 23 is provided so as to extend to the opposite end portion of the opening that receives the conductor lead bar 10 of the cylindrical portion 21. A bolt insertion hole 23a is formed in the flat connection portion 23, and a corresponding bolt insertion hole is also provided in the connection conductor plate 30, and the bolt 42 inserted into both bolt insertion holes is used as a nut on the opposite side. By screwing and fastening, one surface of the flat connecting portion 23 and one surface of the connecting conductor plate 30 are crimped and connected by the fastening force.

The above-mentioned compound is formed on the connection interface between the inner peripheral surface of the cylindrical portion 21 and the outer peripheral surface of the connection portion 11 of the conductor lead bar 10 and the connection interface between one surface of the flat connection portion 23 and one surface of the connection conductor plate 30. C is filled.
The connection work procedure will be described below.
Compound C is applied to the conductor lead bar 10 while polishing the outer peripheral surface of the connecting portion 11. A metal brush (generally made of stainless steel) is used for the polishing operation.
Thereafter, as shown in FIG. 1, the connection portion 11 of the conductor lead bar 10 is disposed in the cylindrical portion 21 of the fixed terminal 20, and the bolt 41 shown in FIG. 2 is tightened to connect the conductor lead bar 10 and the fixed terminal 20. To complete.

  Separately, one surface of the flat connection portion 23 and one surface of the connection conductor plate 30 are similarly polished, and the compound C is applied to one or both of them, and the bolts 42 are tightened to fix the fixed terminal 20 and the connection conductor plate 30. Complete the connection with.

An embodiment in which both the conductor lead bar 10 and the fixed terminal 20 are aluminum conductors, and an embodiment in which one is an aluminum conductor may be implemented.
An embodiment in which both the fixed terminal 20 and the connection conductor plate 30 are aluminum conductors, and an embodiment in which one is an aluminum conductor, may be implemented.
You may implement the connection which applied this compound C to any one among the connection of the conductor extraction stick | rod 10 and the fixed terminal 20, and the connection of the fixed terminal 20 and the connection conductor board 30. FIG. For example, this is a case where the conductor lead bar 10 is an aluminum conductor, and the fixed terminal 20 and the connection conductor plate 30 are conductors such as copper other than aluminum.
According to the above embodiment, the connection interface, at least one of which is an aluminum conductor, is filled with compound C composed of base oil, a thickener, an additive, and metal particles having a particle size of 100 μm or less. The metal particles mediate electrical conduction and good current-carrying characteristics can be obtained while preventing the formation of an oxide film on the surface of the aluminum conductor by blocking contact with the aluminum conductor.
Of course, when both are aluminum conductors, a base oil, a thickener, an additive, and a metal having a particle size of 100 μm or less are formed on the connection interface where either one is an aluminum conductor and the other is other than aluminum (such as copper). Even when the compound C made of particles is filled, the metal particles mediate electrical conduction and obtain good current-carrying characteristics while blocking the contact with oxygen and preventing the formation of an oxide film on the surface of the aluminum conductor. it can. When either one is an aluminum conductor, there is a risk of electrolytic corrosion, and therefore, the surface in contact with both may be plated with zinc or the like.

(Conductivity measurement test)
This is disclosed because a continuity measurement test was conducted. As shown in Table 1, Examples 1 and 2 of the present invention and Comparative Examples 1, 2 and 3 were tested. In all cases, the conductor lead bar 10, the fixed terminal 20, and the connection conductor plate 30 are aluminum conductors according to the above embodiment. However, as shown in Table 1, in Examples 1 and 2, a base oil, a thickener, an additive, and a compound composed of zinc particles having a particle size of 100 μm or less were filled in the connection interface. In this case, a base oil, a thickener, an additive, and a compound composed of zinc particles having a particle size of more than 100 μm are filled in the connection interface. In Comparative Example 2, the base oil, the thickener, the additive, and the particles are filled. A compound composed of zinc particles and silicon carbide particles having a diameter of 100 μm or less was filled in the connection interface. In Comparative Example 3, a compound composed of base oil, thickener, additive, and silicon carbide particles was filled in the connection interface. . Details of each particle size are as shown in Table 1.

The particle size was measured as follows.
That is, the oil content of the compound and the filler were separated with a solvent (toluene), and then the particle size distribution was measured with a laser light diffraction scattering device (particle size analyzer manufactured by Microtrac). Further, the peak value of the particle size distribution was adopted as the particle size value.

The energization characteristic evaluation method is as follows.
The evaluated items are resistance measurement by the DC four-terminal method and a temperature rise value when a large current is applied (the current value is a value obtained by multiplying the allowable current during operation of the power cable by a certain margin).
First, the resistance measurement was evaluated by applying a constant current to the test line including the sample (section A) as shown in FIG. 2, and measuring the voltages in the sections indicated by V1 and V2.
As for the temperature rise value, a large current was applied with the thermocouple 50 attached to the sample at the location shown in FIG. 2, and the change in temperature was evaluated.
The DC conductor resistance (initial value) and the current-carrying conductor resistance were evaluated to be 1.912 × 10 ^ (-8) [Ω / mm] or less, which is the resistance per unit length of the power cable conductor connected to the sample. The results are as shown in Table 1. Among the tested compounds, Examples 1 and 2 showed good characteristics, and the characteristics of the compounds were common to the fact that the filler was only fine zinc particles of 100 μm or less.
From the comparison with the results of Comparative Examples 2 and 3, it was found that silicon carbide particles were not included in the compound, and the comparison with the results of Comparative Example 1 showed that the particle size should be 100 μm or less even with only the zinc particles. .

  When the sample coated with the compound containing silicon carbide of Comparative Example 2 having insufficient properties was disassembled, hard particles were scattered on the surface of aluminum as shown in FIGS. It was confirmed that. FIG. 3 shows a dismantling state of the connecting portion 11 of the conductor lead bar 10 made of an aluminum conductor to which a compound containing silicon carbide has been applied. FIG. 4 shows the dismantling state of the flat connection portion 23 of the fixed terminal 20 made of aluminum conductor, to which a compound containing silicon carbide has been applied.

3 and FIG. 4, it is estimated that the cause of the abnormality in the bolt tightening connection portion is that hard particles are present in the gap between the aluminum rod (10) and the fixed terminal (20), and the metal contacts with each other. It is thought that it is inhibiting.
When used in a compression connection portion by a hydraulic tool, since the aluminum conductor of the connection portion is deformed and connected by compression by the hydraulic tool, the hard particles 103 are compressed by the compression force as shown in FIG. A sufficient contact area between the two connection conductors 101 and 102 is ensured through the gap.
However, as shown in FIG. 5 (b), the bolt tightening connection portion is not applied with a load sufficient to deform the aluminum conductors 101 and 102, so that a sufficient contact area between the two connection conductors 101 and 102 is ensured. Seems not done.
Therefore, it seems that the contact area between the aluminum rod (10) and the fixed terminal (20) is not sufficiently secured. The same applies to the connection between the fixed terminal (20) and the connecting conductor plate (30).
As shown in the above test results, when a compound generally applied to a compression connection portion is applied to a bolt tightening connection portion, sufficient current-carrying characteristics may not be obtained, but a fineness of 100 μm or less, particularly 10 μm or less. Data indicating that the compound to which zinc particles were added showed good properties.

C Compound 10 Conductor extraction rod 11 Connection portion 20 Fixed terminal 21 Cylindrical portion 22 Bolt fastening portion 22a Bolt insertion hole 23 Flat connection portion 23a Bolt insertion hole 30 Connection conductor plate 41 Bolt 42 Bolt

Claims (4)

  In a conductor connection part in which at least one of two connection conductors that are electrically connected to each other for electrically connecting a power cable is an aluminum conductor, a base oil, a thickener, an additive, and a grain are formed on the connection interface. A conductor connecting portion of a power cable, wherein a compound made of metal particles having a diameter of 100 μm or less is filled and connected.   2. The conductor connection part of a power cable according to claim 1, wherein both of the two connection conductors are aluminum conductors.   3. The power cable conductor according to claim 1, wherein the two connection conductors are a conductor lead bar of a terminal connection portion of a power cable and a fixed terminal connected thereto, and the conductor lead bar is an aluminum conductor. 4. Connection part.   The conductor connection part of the power cable according to any one of claims 1 to 3, wherein the two connection conductors are crimp-connected by a fastening force of a bolt.

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