JP2010015946A - Thunder resistant aerial ground wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thunder resistant aerial ground wire, which can be manufactured with existing manufacturing facility and manufacturing management while ensuring stable characteristics for thunder resistance. <P>SOLUTION: In the thunder resistant aerial ground wire, an element wire 20 of an outer layer 200 has an outer diameter larger than that of an element wire 10 of an inner layer 100, whereby the wire has excellent thunder resisting characteristics while having the same outer diameter as a standard AC 150 mm<SP>2</SP>. Therefore, accessories such as compression clamp, linear sleeve, damper and the like used for the standard AC 150 mm<SP>2</SP>can be applied thereto. Further, the wire can be manufactured using an existing cable manufacturing facility without increase in the cost for manufacturing and laying. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a lightning-resistant overhead ground wire, and more particularly, to a lightning-resistant overhead ground wire that has excellent lightning resistance and electric wire strength and can be applied with standard accessories.

  Conventionally, as a means of preventing lightning strikes to overhead power transmission lines, an overhead ground line is provided above the main line of the overhead power transmission line to induce lightning strikes to the overhead ground line to prevent lightning strikes to the main line of the overhead power transmission line. It has been broken. The overhead ground wire is required to have lightning resistance and reliability that are not broken by the energy of lightning strikes, and conductivity that allows the lightning current to escape quickly to the ground.

  As such an aerial ground wire, there is one formed by twisting a plurality of strands provided with a coating material made of aluminum or an aluminum alloy around a core material made of steel (for example, see Patent Document 1).

  The overhead ground wire is located above the transmission line between the towers, so it is susceptible to lightning strikes.If it is melted by the arc heat, the protection function of the transmission line against lightning strikes is lost. There is a possibility that the constituent wires are scattered and come into contact with the power transmission line to cause a short circuit. To prevent this, a lightning-resistant overhead ground wire with improved lightning resistance has been proposed (see, for example, Patent Documents 2 and 3).

  The aerial ground wire described in Patent Document 2 is such that the circumferential end surface of each of the formed strands of the outermost layer twisted together does not coincide with the axis extending radially in a radial direction through the center of the aerial ground wire. It is formed, and at least a part of the circumferential end face is mutually engaged with the adjacent forming element wire, and is held down by any one of the adjacent forming element wires. Thus, even if a disconnection occurs due to lightning strike, it is possible to prevent the strands of the formed strands from returning and spreading.

Moreover, the lightning-resistant electric wire described in Patent Document 3 is a fan-shaped element wire in which a core material made of steel is eccentrically provided so as to have a thick aluminum layer on the outer side of the core material of the element wire, and is generated at the time of a lightning strike. The structure is such that heat is not easily transmitted to the core material.
Japanese Unexamined Patent Publication No. 7-57544 JP-A-7-122117 JP-A-5-62522

  However, according to the aerial ground wire described in Patent Documents 1 to 3, the eccentric structure of the core material and the shape of the formed strands that can be engaged with each other prevent heat generated during lightning strikes from reaching the strands. Therefore, manufacturing equipment and manufacturing management for obtaining stable lightning resistance are required, which increases the manufacturing cost.

  Accordingly, an object of the present invention is to provide a lightning-resistant overhead space that can be manufactured with existing manufacturing equipment and manufacturing management, can obtain stable characteristics with respect to lightning resistance, has excellent electric wire strength, and can be applied with standard accessories. Is to provide a line.

Since the present invention is to achieve the above object, a standard overhead ground line (AC) the same outer diameter and 150 mm ^2, a plurality of first strands forming the inner layer, outer diameter than the first wire Is formed by twisting together a plurality of second strands forming an outer layer outside the inner layer, and has a linear expansion coefficient equivalent to the standard overhead ground wire (AC) 150 mm ² or the standard overhead ground wire (AC) A lightning-resistant overhead ground wire characterized by being smaller than 150 mm ² is provided.

  In the lightning-resistant overhead ground wire, the first strand is formed with an outer diameter of 2.53 mm to 2.8 mm, and the second strand is formed with an outer diameter of 3.8 mm to 4.2 mm. Is preferred. Moreover, it is preferable that the conductivity of the first strand is equal to or smaller than that of the second strand.

  According to the present invention, there is a lightning-resistant overhead ground wire that can be manufactured with existing manufacturing equipment and manufacturing management, can obtain stable characteristics against lightning resistance, has excellent electric wire strength, and can be applied with standard accessories. can get.

  FIG. 1 is a cross-sectional view of a lightning-resistant overhead ground wire according to an embodiment of the present invention.

  This lightning-resistant overhead ground wire 1 includes a core material 11 made of steel, a wire 10 having an aluminum covering portion 12 made of aluminum or an aluminum alloy provided so as to cover the outer periphery of the core material 11, a core material 21 made of steel, It has an aluminum covering portion 22 made of aluminum or an aluminum alloy provided so as to cover the outer periphery of the core material 21, has a strand 20 having an outer diameter larger than that of the strand 10, and consists of seven strands 10. The inner layer 100 has a configuration in which an outer layer 200 composed of nine strands 20 is twisted on the outer side of the inner layer 100.

  The strand 10 has the aluminum coating | coated part 12 formed in the outer layer of the core material 11 by the continuous extrusion. The wire 20 is formed in the same manner as the wire 10.

The strand 10 is formed with an outer diameter of 2.66 mm and an electrical conductivity of 40%, and the strand 20 is formed with an outer diameter of 4.0 mm and an electrical conductivity of 40%. The melting energy of the strand 20 is 563.4 J / cm. The lightning-resistant overhead ground wire 1 is configured such that the outer diameter of the strand 20 is larger than that of the strand 10, but the outer diameter of the lightning-resistant overhead ground wire 1 is configured to be 16 mm, which is the same as the standard AC 150 mm ^2. Has been.

FIG. 2 is a diagram showing the relationship between the melting energy of the strands in the lightning-resistant overhead ground wire and the maximum charge resistance (maximum charge amount that the strands do not melt). Since the melting energy of the strand 20 of the outer layer of the lightning-resistant overhead ground wire 1 of the present embodiment is 563.4 J / cm, it is 200 C (the melting energy of the strand: about 380 J / cm) which is the target value of the charge resistance weight of the summer thunder. cm), which has an excellent lightning resistance performance exceeding 300C (melting energy of strands: about 550 J / cm) which is a target value of the charge resistance weight of winter lightning. In addition, the melting energy of the strand is obtained by the equation shown in Equation 1.

[Effect of the first embodiment]
According to the above-described embodiment, the strand 20 of the outer layer 200 has an outer diameter larger than that of the strand 10 of the inner layer 100, so that it has excellent lightning resistance characteristics without fusing or breaking even if it receives lightning strikes. because it is formed of the same outer diameter and the standard AC150mm ^2, compression clamps used in standard AC150mm ^2, straight sleeve, a damper or the like of the accessory can be used. Moreover, the manufacture using the existing electric wire manufacturing equipment is possible, and the cost required for manufacturing and laying does not increase.

Also, lightning overhead ground wire 1 of this embodiment is a 716.3kg / km and lightweight outer diameter relative to the weight 718.8kg / km of the same standard AC150mm ^2, reinforcement and repair of equipment tower such Is also unnecessary.

  In addition, as a result of intensive studies on the outer diameter of the outer layer 200 with respect to the outer diameter of about 4.0 mm, the present inventors have determined that lightning protection characteristics are within the range of 3.8 mm to 4.2 mm in the outer diameter when 40AC is used. Was confirmed to be improved. When the strand 20 is formed with an outer diameter of 3.8 mm, the melting energy is 509 J / cm, and when the strand 20 is formed with an outer diameter of 4.2 mm, the melting energy is 620.5 J / cm. It exhibits sufficient lightning resistance against the maximum charge resistance of winter lightning.

  Next, examples of the present invention will be described. In the following embodiment, the inner wire 100 constituting the inner layer 100 of the lightning-resistant overhead ground wire 1 described in FIG. 1 has an outer diameter of 2.66 mm, and has different conductivity, so that the inner layer 20AC type (Example 1), the inner layer A 23AC type (Example 2), an inner layer 27AC type (Example 3), and an inner layer 30AC type (Example 4) were produced.

  Further, the strand 20 constituting the outer layer 200 of the lightning-resistant overhead ground wire 1 has an outer diameter of 4.2 mm and 40 AC type, and the strand 10 constituting the inner layer 100 has an outer diameter of 2.53 mm and 20 AC type (Example) 5) The strand 20 constituting the outer layer 200 was made to have an outer diameter of 3.8 mm, 40 AC type, and the strand 10 constituting the inner layer 100 was made to have an outer diameter of 2.80 mm, 23 AC type (Example 6). .

Further, the strand 20 constituting the outer layer 200 is an outer diameter of 4.0 mm and 40 AC type, and the strand 10 constituting the inner layer 100 is an outer diameter of 2.66 mm and 40 AC type as Example 7 as shown in FIG. A standard AC 150 mm ² composed of 19 40 ACs with both inner and outer strands having an outer diameter of 3.2 mm was manufactured as a conventional example. Table 1 shows each example and conventional example. In addition, the numerical value of each type has shown electrical conductivity.

  FIG. 3 shows the sag and tension of the lightning-resistant overhead ground wire, where (a) shows the sag characteristic and (b) shows the tension characteristic. In addition, about the looseness and tension | tensile_strength, it has shown about the characteristic under the temperature conditions of 20 degreeC.

As shown in FIGS. 3A and 3B, the standard AC 150 mm ^{2 of the} conventional example and the lightning-resistant overhead ground wire (40AC) 1 of Example 7 shown in FIG. 1 have the same characteristics in both sag and tension. . For this reason, the existing laying method can be used to replace the overhead ground wire, and standard accessories can be used.

FIG. 4 shows the charge amount and twisted wire breaking load during an arc test for a lightning-resistant overhead ground wire, (a) is a diagram showing the lightning-resistant overhead ground wires of Examples 1, 4, and 7, and (b) is a standard AC 150 mm. it is a diagram showing a ^2. The charge amount is a value that can secure a safety factor of 2.5 (= 76 kN) when the reference tension is 30.4 kN.

As shown in FIG. 4A, the charge amount is 505C in the first embodiment, 428C in the fourth embodiment, and 301C in the seventh embodiment. On the other hand, since the standard AC 150 mm ^{2 of the} conventional example shown in FIG. 4B is 195C, the wire breakage in the lightning-resistant overhead ground wires of Examples 1, 4, and 7 even for lightning strikes in summer and winter lightning It can be seen that a structure is obtained that is less likely to cause stagnation.

  In addition, as a heat resistance test, for each lightning proof overhead ground wire of each example and the conventional example, the wire length is about 3 m, and the constant tension device is used under the condition of EDS (Every Day Stress) at 13.5% UTS (ultimate tensile strength). It was overlaid. And after raising electric wire temperature to instantaneous allowable current 400 degreeC, electricity supply was stopped and it cooled to room temperature, and confirmed the heat history.

After the heat test, no abnormalities such as laughter were observed in the appearance of the lightning-resistant overhead ground wire in both the inner layer 40AC type and the inner layer 30AC type. The inner layer 40AC type of Example 7 is the same line type as the outer layer strand 40AC, the linear expansion coefficient is the same at 15.5 × 10 ⁻⁶ / ° C., and the linear expansion coefficient of the inner layer 30AC type is also the same. Since it is a value substantially equal to 40 AC at 15.0 × 10 ⁻⁶ / ° C., it is considered that the influence of thermal stress is small.

In addition, as a vibration fatigue test, the vibration fatigue test was performed on the lightning-resistant overhead ground wires of each of the examples and the conventional examples by laying the wires at 20% UTS, which is a severe condition of EDS. Vibration fatigue test paste strain gauge on the cable surface, to set the generated distortion amount ^{± 100μst (100 × 10 -6)} , was conducted by vibrating 10 ⁷ times at vibration frequency 20 Hz. After the vibration fatigue test, it was confirmed that the lightning-resistant overhead ground wire of each example was in a healthy state without any abnormalities such as cracks in the aluminum-coated portion of the wire.

  In addition, as a gold wheel passage test, an inner layer 40AC type and inner layer 30AC type lightning-proof overhead ground wire assuming a full-scale extension wire test (gold wheel diameter φ300 mm, horizontal angle 30 °, holding angle 60 °, round-trip 20 Times). During the gold wheel test, no laughter occurred in each part of the lightning-resistant overhead ground wire of each example. Further, as a result of measuring the pitch and the outer diameter of the electric wire when passing through the gold wheel, no change was observed in the outer diameter and the pitch of the electric wire even after passing 20 times. After the test, the lightning-resistant overhead ground wire was disassembled and the nicking rate was investigated. As a result, the maximum nicking rate was 10% or less of the standard value, and it was confirmed that there was no practical problem.

In addition, as an accessory test, a linear gripping force test was conducted on the lightning-resistant overhead ground wire of each example using a compression clamp and a linear sleeve, which are standard products for standard AC 150 mm ² . As a result, the inner layer 40AC type and the inner layer 30AC type lightning-resistant overhead ground wire showed a standard value of 95% UTS or more, and it was confirmed that standard accessories could be applied. From the results of the above test and the like, the lightning-resistant overhead ground wire of the present example has excellent electric wire strength.

FIG. 1 is a cross-sectional view of a lightning-resistant overhead ground wire according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the melting energy of the strands in the lightning-resistant overhead ground wire and the maximum charge resistance (maximum charge amount that the strands do not melt). FIG. 3 shows the sag and tension of the lightning-resistant overhead ground wire, where (a) shows the sag characteristic and (b) shows the tension characteristic. FIG. 4 shows the charge amount and twisted wire breaking load during an arc test for a lightning-resistant overhead ground wire, (a) is a diagram showing the lightning-resistant overhead ground wires of Examples 1, 4, and 7, and (b) is a standard AC 150 mm. it is a diagram showing a ^2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Lightning resistance ground wire, 10, 20 ... Wire, 11, 21 ... Core material, 12, 22 ... Aluminum coating material, 100 ... Inner layer, 200 ... Outer layer

Claims (3)

A plurality of first strands having the same outer diameter as a standard overhead ground wire (AC) 150 mm ² , an outer diameter larger than the first strand, and an outer layer outside the inner layer It is formed by twisting a plurality of second strands forming the, is smaller than the linear expansion coefficient of the standard ground wire (AC) 150 mm ² and equal to or above the standard ground wire (AC) 150 mm ² A lightning-resistant overhead ground wire. The first strand is formed with an outer diameter of 2.53 mm to 2.8 mm,
2. The lightning-resistant overhead ground wire according to claim 1, wherein the second strand has an outer diameter of 3.8 mm to 4.2 mm.   3. The lightning-resistant overhead ground wire according to claim 1, wherein the first strand has a conductivity equal to or smaller than that of the second strand. 4.

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