JPH10321048A - Tension member and lightweight/low slackness overhead wire using the tension member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tension member which is lightweight with low increase in slackness accompanying temperature rise, and superior in resistance to crash. SOLUTION: This tension member is formed by twisting a plurality of wire rods of a fiber-reinforced plastic complex using a PBO fiber set as a reinforcing material 1 and a heat-resistant resin as a matrix 2. The exterior of the tension member is constrained by an aluminum-based, copper-based, or tape 3 of the heat-resistance resin. The relation 40 × DR<P is preferably satisfied between Dr and P, where, Dr is the core diameter of a layer and P is pitch length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension member used for an overhead transmission line and a lightweight low-relaxation overhead line using the same, and more particularly, to a lightweight member having excellent strength characteristics, good weather resistance, and a high temperature environment. The present invention relates to a tension member that hardly causes an increase in the sag below, and hardly causes a crush in the radial direction, and a lightweight, low-sag, overhead electric wire using the same.

[0002]

2. Description of the Related Art Conventionally used overhead power transmission lines are:
A steel core obtained by twisting a plurality of steel wires at a predetermined pitch length is used as a tension member, and a transmission line made of, for example, Al or an Al alloy is twisted and arranged outside the tension member. Then, the whole is stretched between the steel towers with high tension to form a transmission line.

However, in the case of the above-described steel core Al stranded wire, since the weight per unit length of the steel core as the tension member is large, the steel core Al stranded wire is likely to hang down by its own weight. The coefficient of thermal expansion of the steel wire is a positive value. Therefore, for example, the more the load current of the transmission line is increased, the higher the temperature of the line is correspondingly. Then, the temperature of the tension member rises accordingly, so that the tension member expands linearly, causing an increase in the sag. Therefore, when trying to increase the transmission capacity,
It is necessary to increase the height of the steel tower to be built in anticipation of the increase in the sag due to the rise in the wire temperature, and an increase in the construction cost is inevitable.

In view of the above, various types of tension members that are lightweight and have excellent strength characteristics have been provided in place of the above-described conventional steel cores. For example, a wire rod made of a fiber-reinforced plastic (metal) composite using an organic fiber such as aramid fiber as a reinforcing material and a matrix of various resins or materials such as aluminum, a carbon fiber, a silicon carbide fiber, an alumina fiber, Boron fiber,
A wire made of a fiber-reinforced plastic (metal) composite using inorganic fibers such as glass fibers as a reinforcing material and a matrix of various resins or materials such as aluminum has been proposed (JP-A-60-37606). JP, JP-A-62-86606, JP-A-1-104
732, JP-A-2-181303, etc.).

[0005]

However, in the case of the above-mentioned wire rod which has been proposed as a tension member replacing the steel core, the following problem occurs when it is actually used as a tension member. First, since the temperature of the working overhead transmission line rises, the temperature of the tension member also rises. The temperature of the tension member varies depending on the magnitude of the load current flowing through the transmission line, but may reach about 300 ° C.

[0006] Even in such a high temperature, the linear expansion coefficient of the tension member needs to be small so as not to cause a large increase in the sag of the tension member. However, when the reinforcing material is a glass fiber or a boron fiber, the linear expansion coefficient of the tension member using them is as large as about 7 to 8 × 10 ⁻⁶ / ° C., which suppresses the increase in the sag at high temperatures. Is not satisfactory.

Further, in the case of a tension member using silicon carbide fiber, alumina fiber, aramid fiber or the like as a reinforcing material, the tensile strength of these fibers is not so high, so that the strength characteristics of the tension member are not satisfactory.
Since the heat resistance of aramid fiber is about 180 ° C,
I am dissatisfied with the fact that thermal degradation is likely to occur when the wire temperature rises.

Furthermore, inorganic fibers such as carbon fiber, silicon carbide fiber, and alumina fiber all have low elongation and poor toughness, so the following problem occurs, and it is not preferable to use these inorganic fibers for the tension member. That is, when constructing an overhead transmission line having a tension member made of a wire made of an inorganic fiber as a reinforcing material as described above, when an extension wire or a pulley attached to the electric wire passes through the transmission line during the construction, tension is applied. This is because the member receives a large bending stress, which may cause breakage of the tension member and cracking of the matrix.

[0009] In addition, inorganic fibers have a disadvantage that they are generally weak against crushing force in the radial direction. Therefore, for example, when an overhead transmission line is compressed by a compression clamp or the like and retained on a steel tower, the tension member is crushed in the radial direction by the compression force at that time, and there is also a problem that it is not possible to secure the yield strength according to the design standard. Occur. And there is a problem that the manufacturing cost of the tension member using these inorganic fibers is much higher than that using an organic fiber described later, which makes actual use considerably difficult.

On the other hand, in the case of a tension member in which the reinforcing material is an organic fiber, the organic fiber is easily deteriorated by heat as compared with the inorganic fiber, and generally has a property that the strength is reduced by exposure to ultraviolet rays. . Therefore, the strength of the tension member decreases with time in response to sunlight, and the transmission member may lose its ability to support the transmission line.

Further, in the case of a tension member using organic fiber as a reinforcing material, for example, it is conceivable that a fire or the like may cause combustion, so that it is necessary to take measures to prevent combustion. The present invention solves the above-mentioned problems in a conventionally proposed tension member made of a fiber reinforced plastic (metal) composite wire, and is not only lightweight and excellent in strength properties but also relaxed in a high temperature environment. It is an object of the present invention to provide a novel tension member which has a small increase in degree, has good weather resistance, and is hardly crushed in the radial direction, and a lightweight low-loose overhead electric wire using the same.

[0012]

According to the present invention, there is provided a fiber-reinforced plastic composite wire comprising a polyparaphenylenebenzobisoxazole fiber as a reinforcing material and a heat-resistant resin as a matrix. A tension member characterized by being constrained by a tape or a tube made of aluminum, copper or the above-mentioned heat-resistant resin, and an aluminum or copper material outside the tension member. A light-weight, low-loose overhead wire is provided, in which conductors are arranged and twisted.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a tension member will be described. FIG. 1 shows an example A of a tension member of the present invention.
FIG. This tension member A
Twist a plurality of wires a (described below) (seven wires),
By wrapping the outside of the wire with a thin tape, the entire wire a is restrained to prevent the wire a from scattering.

The restriction of the wire a is not limited to the wrapping of the tape 3 as shown in the figure, and the tape 3 may be wound with an appropriate gap without wrapping. Further, a tube may be put on the tension member instead of the tape. Here, as shown in FIG. 2 which is a cross-sectional view, the wire a is made of a polyparaphenylene benzobisoxazole fiber (poly (p-phenylene-2,6-benzobisoxazole) fiber, hereinafter referred to as a PBO fiber) 1 as a reinforcing material. The matrix 2 in which the fibers are embedded is a fiber-reinforced plastic composite wire rod made of a heat-resistant resin.

The PBO fiber has the following formula:

[0016]

Embedded image

This is a fiber obtained by spinning liquid crystal of polyparaphenylene benzobisoxazole having a repeating unit of This PBO fiber has a tensile strength (Ts) of about 5.50 GPa,
Elastic modulus (E) of about 280 GPa, melting point of 600 to 650
° C, oxygen index 50-55, density (ρ) about 1.56 g /
cm ³ , a coefficient of linear expansion (α) of about −6 × 10 ⁻⁶ / ° C., high strength, high elasticity, excellent heat resistance and flame retardancy,
Moreover, it is lightweight. Since the coefficient of linear expansion is a negative value, it has a property that it contracts with increasing temperature. However, on the other hand, it also has the property of being easily deteriorated by ultraviolet rays.

The heat-resistant resin of the matrix 2 that binds the PBO fibers 1 is, for example, a resin that does not undergo thermal melting or thermal decomposition and hardly causes thermal degradation even when the electric wire temperature rises to around 300 ° C. Is used.
For example, a polyimide resin, a polyamideimide resin, a thermoplastic polyimide resin, polyetheretherketone, polyphenylene sulfide, a fluorine resin, and the like can be given.

In the wire a, it is preferable that the volume occupancy of the PBO fiber 1 is set to 15 to 90% (therefore, the volume occupancy of the matrix 2 is 10 to 85%). When the volume occupation ratio of the PBO fiber 1 is smaller than 15%, the strength characteristics of the entire wire, particularly the tensile strength, begin to decrease and the effect as a tension member decreases, and the effect of reducing the linear expansion coefficient of the entire wire is sufficiently improved. Can not be demonstrated. When the volume occupancy of the PBO fiber 1 is greater than 90%, the matrix 2
Is too small, the PBO fibers 1 are not sufficiently bound, so that the strength characteristics of the entire wire begin to deteriorate. A particularly preferred volume occupancy of the PBO fiber is 40 to 6
0%.

When the matrix 2 is dispersed with various types of carbon black, lead glass powder, and an ultraviolet ray shielding material such as HALS (hindered amine stabilizer), the photodegradation of the PBO fiber as a reinforcing material is reduced. As a result, the weather resistance of the wire a is enhanced, and the wire a can be used as a tension member for a long period of time. In that case, if the amount of the ultraviolet ray blocking material is too large,
The amount of dispersion is preferably set to a volume equivalent to 1 to 30% with respect to the volume occupancy of the matrix since the strength of the entire wire is reduced.

The wire a can be manufactured as follows. That is, for example, when the matrix is a thermosetting resin such as a polyimide resin or a polyamideimide resin, first, a predetermined number of PBO fibers are bundled,
The bundle is immersed in an uncured resin liquid to impregnate the fiber bundle with the resin. Then, after passing through a die having a predetermined diameter to remove the residual resin and form the impregnated resin into a wire in a semi-dried state, the wire is heated to a predetermined temperature to thermally cure the resin. As a result, the thermoset resin and each PBO
The interface with the fiber is seized and integrated with each other to form a composite there.

When the matrix is a resin such as thermoplastic polyimide, polyetheretherketone, polyphenylene sulfide, or a fluororesin, these resins are formed by extrusion coating molding used in the production of electric wires and cables. By applying the method, the surface of the bundle of PBO fibers can be formed by extrusion coating. At the time of this extrusion coating, since the resin is in a plastic state, it penetrates to the center of the fiber bundle by the pressure at the time of molding, and buries the fiber bundle in contact with the surface of each PBO fiber.

When a predetermined amount of the above-mentioned ultraviolet ray blocking material is blended with the resin used at the time of impregnation of the resin or at the time of extrusion coating, a wire rod which is unlikely to cause light deterioration can be obtained. In manufacturing the tension member of the present invention, first, the wire a described above is twisted. In this case, when the pitch length when twisting the wire a is P and the layer core diameter of the tension member after twisting is Dr, P and D
It is preferable to satisfy the relationship of 40 × Dr <P between r. More preferably, 100 × Dr ≦ P ≦ 200
× Dr is satisfied.

The layer diameter Dr mentioned here is expressed by the following equation: D
It means a value calculated based on r = D−d. In the above formula, d represents the diameter of each twisted wire a,
D represents the maximum diameter of the twisted tension member.
For example, in the case of the tension member A in FIG. 1, the cross section after the twisting is in a state where seven wire rows are stacked as shown in FIG. Here, the diameter of the wire a is represented by d =
When the outer diameter of the seven strands is D, the layer core diameter Dr of the tension member A is Dr = D−d = 9−3.
= 6 mm.

The tension member according to the present invention has a P value and a Dr value.
The following effects are exhibited by relating the values as described above. First, when a transmission line using this tension member is installed between steel towers, the substantial length of the wire a located between the steel towers (diameter length: usually 200 to 500 m) is twisted at a short pitch length. It is shorter than when combined.

Therefore, the substantial weight of the tension member between the diameters is reduced, and the absolute value of the extension due to the thermal expansion of the tension member is shortened even when the temperature of the electric wire increases, and the sag increases. Is suppressed. Further, when the above relationship is established, the mutual relationship of the twisted wire members a approximates a state in which the wires a are in contact with each other and are arranged in parallel with each other. Even when a compressive force is applied in the direction, it is difficult for the tension member to collapse. That is, it becomes easy to secure the yield strength of the design standard.

Since the wire a is a fiber-reinforced plastic composite, it is difficult to apply a spiral preform in the twisting step as in the case of a steel core. Accordingly, if the wire a is simply twisted, a problem that the whole is separated by the springback force of each wire a when the end is cut is likely to occur. In order to prevent such a problem, according to the present invention, as shown in FIG. 1, the outside of the twisted wire a is wrapped around the wire 3 with a tape 3 to restrain the entire wire a, thereby preventing the wire a from coming apart. I do.

The restriction of the wire a is not limited to the wrapping of the tape 3 as shown, but the tape 3 may be wound with an appropriate gap without wrapping. Further, a tube may be put on the tension member instead of the tape. As the tape or tube, for example, a tape or tube made of an aluminum-based or copper-based material, or a tape or tube made of a heat-resistant resin such as a polyimide resin or a fluorine-based resin is used.

If the thickness of the tape or tube is too large, it will affect the outer diameter of the finished wire as a whole, so the thinner the better, the better. However, the thickness is usually about 50 to 200 μm. If so, the effect on the outer diameter of the finished wire is small. Next, FIG. 4 shows an example of a lightweight low-loose overhead wire according to the present invention.

This electric wire is obtained by arranging a plurality of conductors 4 as transmission lines outside the tension member A shown in FIG. 1 and twisting them. The conductor 4 is made of an aluminum-based material such as aluminum alone or an aluminum alloy, or a copper-based material such as copper alone or a copper alloy. This is because each of these materials has a small electric resistance and can reduce a loss during power transmission.

The cross-sectional shape of the conductor 4 is not limited to a circle, but may be a segment shape. The segment shape is preferable because the conductor 4 can be arranged without a dead space. Since this overhead electric wire uses the tension member A, it is lightweight as a whole, has good weather resistance, suppresses the increase in sag in a high-temperature environment, and has a radial direction even when it is fixed to a steel tower. It has the property of not being easily crushed.

[0032]

【Example】

Example 1 Toyobo Co., Ltd. PBO fiber (linear expansion coefficient: -6 × 10
⁻⁶ / ° C.) into a bundle of 1.9 mm in thickness by tying about 3,000 deniers. The bundle is continuously run through an uncured polyimide resin having a viscosity of 20 poise, and then passed through a die having a diameter of 3 mm. The residual resin was removed, and the resin was further introduced into a heating furnace at a temperature of 350 ° C. to thermally cure the polyimide resin.
A wire rod a having the composite structure shown by.

By changing the convergence state of the PBO fibers during the production of the wire rod a, the volume occupancy of the PBO fibers is reduced to 4%.
Two types of wires (diameter 3.0 mm) of 0% and 60% were produced. After twisting each of the seven wires at a pitch length of 600 mm, an aluminum tape was halved on the outside.
The tension member A was manufactured by wrapping. In each of these tension members A, Dr is 6.0 mm,
P is 600 mm, which satisfies the relationship of 40 × Dr <P.

Outside the tension member A, the cross section is
Aluminum with an equivalent diameter of 2.85 mm
Twenty-four bodies are arranged and twisted, and the total cross-sectional area is 160
mm ^TwoOverhead wire. For each overhead wire obtained,
Under the following catenary wire design conditions, the diameter span (S) is shown in Table 1.
And the wire temperature became 20 ° C and 200 ° C
The sag at the time of was calculated.

Overhead wire design conditions: Maximum working tension 25.5 GP
a, High temperature season 15 ° C, wind pressure 10.2MPa, low temperature season -15 ° C, wind pressure 5.1MPa, ice cover 6mm, specific gravity 0.1
9. For comparison, the same calculation was performed for a conventional invar core aluminum stranded wire having the same sectional structure.

The above results are collectively shown in Table 1.

[0037]

[Table 1]

As is evident from Table 1, the overhead wire of the present invention suppresses the increase in the sag even when the wire temperature increases. For example, when the diameter length is 500 m, the volume occupancy of the PBO fiber is 40% even though the invar electric wire has a 9% increase in the sag between a temperature of 20 ° C. and 200 ° C. With the overhead electric wire of the present invention, the sag increases only by about 2.6%.

In addition, in the overhead electric wire of the present invention, the magnitude of the sag varies depending on the volume occupancy of the PBO fiber. It can be seen that the larger the volume occupancy, the smaller the sag. However, if the volume occupation ratio is too large, the production cost is increased, which is not preferable.

[0040]

As is apparent from the above description, claim 1
The tension member of PB shows a negative linear expansion coefficient of PB
O-fiber is used as a reinforcing material, and a wire made of a heat-resistant resin as a matrix is twisted, and its outside is constrained by an aluminum-based, copper-based or heat-resistant resin tape or tube. In addition, even under a high temperature environment, the amount of thermal expansion is small, the increase in sag is suppressed, and the heat resistance is good.

In the tension member according to the second aspect, when the above-mentioned wires are twisted, the relationship between the pitch length (P) and the core diameter (Dr) is set to 40 × Dr <P. Excellent crush resistance. In the tension member of claim 3, since the ultraviolet ray blocking material is dispersed in the heat resistant resin,
Light deterioration of the PBO fiber is suppressed.

The overhead electric wire according to the fourth aspect uses the above-mentioned tension member, so that it is lightweight as a whole, and the sag increases little even if the electric wire temperature rises due to an increase in load current. Therefore, this overhead transmission line can reduce the burden on the tower, and can also lower the tower. In other words, conversely, even if the light-weight, low-sagging overhead electric wire of the present invention is installed in an existing steel tower, a larger load current can be applied to the electric wire than in the past to increase the power transmission capacity.

[Brief description of the drawings]

FIG. 1 is a partial perspective view showing a tension member A of the present invention.

FIG. 2 is a sectional view showing a wire a used for a tension member of the present invention.

FIG. 3 is an explanatory diagram showing a cross-sectional state of a tension member A.

FIG. 4 is a partial perspective view showing a light weight and low sag overhead electric wire of the present invention.

[Explanation of symbols]

 a Wire rod of fiber-reinforced plastic composite 1 PBO fiber (reinforcing material) 2 Heat-resistant resin (matrix) 3 Tape 4 Conductor

Claims (4)

[Claims] 1. A fiber-reinforced plastic composite wire having a polyparaphenylene benzobisoxazole fiber as a reinforcing material and a heat-resistant resin as a matrix, a plurality of wires being twisted, and the outside thereof being an aluminum-based, copper-based or heat-resistant resin. A tension member restrained by a tape or a tube comprising: 2. The layer core diameter of the tension member is Dr,
When the pitch length is P, between Dr and P, 40 × D
2. The tension member according to claim 1, wherein a relationship of r <P is satisfied. 3. The tension member according to claim 1, wherein an ultraviolet ray blocking material is dispersed in the heat-resistant resin. 4. A lightweight, low-sagging overhead electric wire, wherein a conductor made of aluminum or copper is arranged and twisted outside the tension member according to claim 1.