Aluminum alloy conductor, two-stage aging strengthening method thereof and overhead transmission conductor

Abstract

The invention discloses an aluminum alloy conductor, a two-stage aging strengthening method thereof and an overhead transmission conductor. The tensile property and the heat resistance of the aluminum alloy conductor subjected to two-stage aging strengthening can be improved. The two-stage aging strengthening method for the aluminum alloy conductor comprises the steps that the temperature of the manufactured aluminum alloy conductor is increased to a first-stage aging temperature T1, and heat preservation is conducted for a first-stage aging duration S1; wherein 175 DEG C < = T1 < = 185 DEG C, and 5.5 h < = S1 < = 6.5 h; then, the temperature of the aluminum alloy conductor is increased to the second-stage aging temperature T2, and heat preservation is conducted for the second-stage aging time S2; wherein 195 DEG C < = T2 < = 205 DEG C, and 5.5 h < = S2 < = 6.5 h; and cooling the aluminum alloy conductor.

Description

Technical Field

[0001] The present invention belongs to the technical field of overhead transmission conductors, and particularly relates to an aluminum alloy conductor, a double-stage aging strengthening method thereof, and an overhead transmission conductor. Background Art

[0002] Overhead transmission conductors shoulder the important mission of long-distance power transmission. Transmission lines often cross areas where rain, snow, and ice disasters occur frequently. For example, the southern regions of China are typical representatives. In the prior art, in order to reduce the line loss during power transmission, the operating temperature of traditional transmission conductors is usually set at 70°C. In harsh environments with low temperature (for example, below 0°C) and high humidity (for example, above 90%), traditional transmission conductors are extremely likely to form ice coatings on the surface. This will not only significantly increase the self-weight of the conductor and the sag, but may even cause major accidents such as wire breakage and tower collapse in severe cases, thereby leading to large-scale power outages in the power grid and causing incalculable huge economic losses.

[0003] In recent years, although certain progress has been made in the technology of conductor anti-icing, in the face of complex and changeable line environments, the prior art still exposes many limitations. For example, traditional anti-ice and snow conductors mostly adopt passive anti-icing technologies such as super-hydrophobic coatings and water-repellent materials. Although these technologies can delay the formation of ice layers to a certain extent, they have inherent defects such as short anti-icing life and poor weather resistance, and cannot actively remove ice and snow coverage, making it difficult to fundamentally solve the icing problem.

[0004] In order to fundamentally solve the icing problem, it is necessary to use the thermal de-icing technology. Its principle is to heat the conductor by passing an electric current through the conductor to achieve de-icing. However, during the de-icing process, this technology has to interrupt the power transmission function of the conductor, affecting the normal supply of electricity. In addition, this method has huge energy consumption, slow response speed, and conventional conductors (steel-cored aluminum stranded wires) have poor heat resistance, and deform greatly when heated, resulting in problems such as increased sag and reduced breaking strength, posing a serious threat to the safety of line operation.

[0005] Existing steel-cored aluminum stranded wires include a steel core wire and an aluminum stranded wire. To solve the problems of increased sag and reduced breaking strength when the conductor is heated, it is necessary to improve the tensile strength and heat resistance of the steel core wire and / or the aluminum stranded wire. Under the prior art, the steel core wire has generally adopted ultra-high-strength materials, and it is difficult to improve the problems of increased sag and reduced breaking strength when the conductor is heated by changing the material properties of the steel core wire. Therefore, how to improve the tensile strength and heat resistance of the aluminum stranded wire is the problem to be solved currently. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an aluminum alloy conductor, a double-stage aging strengthening method thereof, and an overhead transmission conductor in view of the above deficiencies existing in the prior art, which can improve the tensile properties and heat resistance of the aluminum alloy conductor after double-stage aging strengthening.

[0007] In a first aspect, an embodiment of the present invention provides a two-stage aging strengthening method for an aluminum alloy wire, the method comprising: raising the temperature of the fabricated aluminum alloy wire to a first-stage aging temperature T1 and maintaining the temperature for a first-stage aging duration S1; wherein, 175°C ≤ T1 ≤ 185°C, 5.5 h ≤ S1 ≤ 6.5 h; then raising the temperature of the aluminum alloy wire to a second-stage aging temperature T2 and maintaining the temperature for a second-stage aging duration S2; wherein, 195°C ≤ T2 ≤ 205°C, 5.5 h ≤ S2 ≤ 6.5 h; and then cooling the aluminum alloy wire.

[0008] In some embodiments, the cooling of the aluminum alloy wire specifically comprises: placing the aluminum alloy wire in the air for natural cooling until the cooling duration of the aluminum alloy wire is S3, S3 ≥ 8 h.

[0009] Thus, for the two-stage aging strengthening method for an aluminum alloy wire provided by the embodiment of the present invention, by raising the temperature of the fabricated aluminum alloy wire to the first-stage aging temperature T1 and maintaining the temperature for the first-stage aging duration S1, the first-stage aging treatment of the aluminum alloy wire can be completed; by raising the temperature of the aluminum alloy wire to the second-stage aging temperature T2 and maintaining the temperature for the second-stage aging duration S2, the second-stage aging treatment of the aluminum alloy wire can be completed; and after cooling the aluminum alloy wire, the two-stage aging strengthening of the aluminum alloy wire is completed. After verification by the inventor, by making 175°C ≤ T1 ≤ 185°C, 5.5 h ≤ S1 ≤ 6.5 h, 195°C ≤ T2 ≤ 205°C, 5.5 h ≤ S2 ≤ 6.5 h, compared with the single-stage aging and the aluminum alloy wire without aging treatment, the tensile strength and heat resistance of the aluminum alloy wire after two-stage aging strengthening can be improved. Therefore, when using the aluminum alloy wire as the aluminum stranded wire of an overhead transmission line, the overall tensile strength and heat resistance of the overhead transmission line can be improved, thereby improving the phenomena of increased sag and reduced breaking strength when the overhead transmission line is heated.

[0010] In a second aspect, an embodiment of the present invention provides an aluminum alloy wire, which is obtained by treating with the two-stage aging strengthening method in the first aspect.

[0011] In a third aspect, an embodiment of the present invention provides an overhead transmission line, which includes a load-bearing part and a conductive part. The load-bearing part is formed by concentrically stranding a plurality of load-bearing single wires. The conductive part is formed by stranding a plurality of conductive single wires on the outer circumferential surface of the load-bearing part; the conductive single wires adopt the aluminum alloy wire in the second aspect.

[0012] In some embodiments, the material of the conductive single wire is an existing 8000 series aluminum-zirconium alloy, where the zirconium content is 0.1% to 0.2%; the tensile strength of the conductive single wire is greater than or equal to 180 MPa, the heat resistance of the conductive single wire is greater than or equal to 92%, and the conductivity of the conductive single wire is greater than or equal to 60.5% IACS.

[0013] In some embodiments, the operating temperature of the overhead transmission line is T3, where 145°C ≤ T3 ≤ 155°C.

[0014] In some embodiments, multiple conductive single wires are spliced and stranded in multiple layers along the circumferential direction of the load-bearing part in sequence to form the conductive part.

[0015] In some embodiments, the cross-section of the conductive single wire is all in a T shape; or, among any two adjacent layers of the conductive single wires, the cross-section of the conductive single wire in one layer is in a Z shape, and the cross-section of the conductive single wire in the other layer is in an S shape.

[0016] In some embodiments, the load-bearing single wire is a galvanized steel strand, and the tensile strength of the load-bearing single wire is greater than or equal to 1500 MPa.

[0017] In some embodiments, the overhead transmission line further includes a sensing optical fiber and an armor layer. The sensing optical fiber is arranged in the area surrounded by the multiple load-bearing single wires; the sensing optical fiber is connected to an external distributed optical fiber sensor, and the distributed optical fiber sensor is used to monitor the operating temperature and stress changes of the overhead transmission line through the sensing optical fiber, so as to judge whether there is icing on the overhead transmission line according to the operating temperature and stress changes of the overhead transmission line. The armor layer is arranged between the sensing optical fiber and the inner circumferential surface of the load-bearing part for protecting the sensing optical fiber.

[0018] The aluminum alloy wire provided by the embodiment of the present invention has good tensile strength and heat resistance, meeting the high requirements of the transmission line for materials. The overhead transmission line provided by the embodiment of the present invention can improve the overall tensile strength and heat resistance of the overhead transmission line, and can improve the safety of the overhead transmission line during daily operation. Description of the Drawings

[0019] Figure 1 : is a flowchart of a two-stage aging strengthening method for an aluminum alloy wire provided by an embodiment of the present invention;

[0020] Figure 2 : is a cross-sectional view of an overhead transmission line provided by an embodiment of the present invention;

[0021] Figure 3 : is a cross-sectional view of another overhead transmission line provided by an embodiment of the present invention.

[0022] Among them, 1 - sensing optical fiber; 2 - armored layer; 3 - load - bearing single wire; 4 - conductive single wire. Specific embodiments

[0023] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0024] Embodiment 1:

[0025] As Figure 1 shown, the present invention provides a two - stage aging strengthening method for aluminum alloy wires, and the two - stage aging strengthening method for aluminum alloy wires is applied to the post - treatment process of aluminum alloy wires for heat - treating the manufactured aluminum alloy wires.

[0026] Exemplarily, the above - mentioned aluminum alloy wire can be an aluminum stranded wire for manufacturing overhead transmission wires, for example, a single - wire conductive single wire formed by a drawing process, and after the conductive single wires are stranded, an aluminum stranded wire in the overhead transmission wire (i.e., the conductive part of the overhead transmission wire described later) is formed.

[0027] As Figure 1 shown, the two - stage aging strengthening method for aluminum alloy wires includes: steps S100 - S300.

[0028] S100. Raise the temperature of the manufactured aluminum alloy wire to the first - stage aging temperature T1 and keep it warm for the first - stage aging duration S1; wherein, 175°C ≤ T1 ≤ 185°C, 5.5 h ≤ S1 ≤ 6.5 h.

[0029] Exemplarily, the aluminum alloy wire can be placed in an industrial aging furnace for heating and insulation.

[0030] Exemplarily, the first - stage aging temperature T1 can be 175°C, 180°C or 185°C, etc., and the first - stage aging duration S1 can be 5.5 h, 6 h or 6.5 h, etc.

[0031] Those skilled in the art can understand that step S100 is to perform the first - stage aging treatment on the aluminum alloy wire, which can enable the solute atoms in the aluminum alloy wire to fully diffuse and form a uniformly distributed GP zone (Guinier - Preston zone), providing a good tissue basis for the subsequent second - stage aging.

[0032] S200. Then raise the temperature of the aluminum alloy wire to the second - stage aging temperature T2 and keep it warm for the second - stage aging duration S2; wherein, 195°C ≤ T2 ≤ 205°C, 5.5 h ≤ S2 ≤ 6.5 h.

[0033] Exemplarily, the secondary aging temperature T2 can be 195°C, 200°C, 205°C, etc., and the primary aging duration S2 can be 5.5 h, 6 h, 6.5 h, etc.

[0034] That is, step S100 is to perform secondary aging treatment on the aluminum alloy wire, which can further grow the GP zone and transform it into a stable precipitation phase, significantly improving the strength and heat resistance of the aluminum alloy wire.

[0035] S300. Then, cool the aluminum alloy wire.

[0036] In some examples, cooling the aluminum alloy wire specifically means: placing the aluminum alloy wire in the air for natural cooling until the cooling duration of the aluminum alloy wire is S3, where S3 ≥ 8 h.

[0037] Exemplarily, the cooling duration S3 of the aluminum alloy wire can be 8 h, 9 h, 10 h, etc.

[0038] This natural cooling method avoids the residual stress that may be caused by rapid cooling, ensuring the dimensional stability and mechanical properties of the aluminum alloy wire.

[0039] Through the above method, double-stage aging strengthening of the aluminum alloy wire is achieved. By controlling the temperature and duration of double-stage aging strengthening, the tensile strength and heat resistance of the aluminum alloy wire can be improved. Therefore, when using this aluminum alloy wire as the aluminum stranded wire of an overhead transmission line, the overall tensile strength and heat resistance of the overhead transmission line can be improved, thereby improving the phenomena of increased sag and reduced breaking strength when the overhead transmission line is heated.

[0040] The inventor conducted two detailed tests on the mechanical and electrical properties of the aluminum alloy wire after the above double-stage aging strengthening to verify the above beneficial effects.

[0041] The first test:

[0042] The aluminum alloy (8000 series aluminum-zirconium alloy) wire with a wire diameter of 3.42 mm was used for the test. The test included a first experimental group, a first control group, and a second control group.

[0043] The first experimental group used the double-stage aging strengthening method provided by the embodiment of the present invention to process the aluminum alloy wire. The processing process of the aluminum alloy wire was: for primary aging, the temperature was raised to 180 ± 2°C and the holding time was 6 h. For secondary aging, after the temperature was raised to 200 ± 2°C, it was held for another 6 h, and then taken out of the furnace and cooled in the air, with the cooling time not less than 8 hours.

[0044] The first control group used single-stage aging in the prior art for processing. The processing process of the aluminum alloy wire was: the single-stage aging temperature was 160°C, the holding time was 10 h, and then taken out of the furnace and cooled in the air.

[0045] The second control group did not process the aluminum alloy wire.

[0046] Partial mechanical and electrical performance indexes of the above three groups of aluminum alloy wires are shown in Table 1. The test temperatures of tensile strength, conductivity, and elongation are all 23°C.

[0047] Table 1

[0048]

[0049] As can be seen from Table 1, the tensile strength, elongation, and residual tensile strength ratio (230°C) of the first experimental group are all higher than those of the first control group and the fourth control group, and the conductivity is roughly the same.

[0050] Second test:

[0051] The aluminum alloy (8000 series aluminum-zirconium alloy with zirconium content of 0.1% - 0.2%) wire with a wire diameter of 4.22 mm was used for the test. The test included the second experimental group, the third control group, and the fourth control group.

[0052] The second experimental group processed the aluminum alloy wire by using the two-stage aging strengthening method provided by the embodiment of the present invention. The processing process of the aluminum alloy wire was as follows: for the first-stage aging, the temperature was raised to 180 ± 2°C and the holding time was 6 h; for the second-stage aging, after the temperature was raised to 200 ± 2°C, it was held for another 6 h, and then taken out of the furnace and cooled in the air, and the cooling time was not less than 8 hours.

[0053] The third control group was processed by using single-stage aging in the prior art. The processing process of the aluminum alloy wire was as follows: the single-stage aging temperature was 160°C, the holding time was 10 h, and then taken out of the furnace and cooled in the air.

[0054] The fourth control group did not process the aluminum alloy wire.

[0055] Partial mechanical and electrical performance indexes of the above three groups of aluminum alloy wires are shown in Table 2. The test temperatures of tensile strength, conductivity, and elongation are all 23°C.

[0056] Table 2

[0057]

[0058] As can be seen from Table 2, the tensile strength, elongation, and residual tensile strength ratio (230°C) of the second experimental group are all higher than those of the third control group and the fourth control group, and the conductivity is roughly the same.

[0059] Based on the data from the two tests, it can be seen that after treating the aluminum alloy wire with the two-stage aging strengthening method provided by the embodiment of the present invention, the conductivity remains basically unchanged, but the tensile strength can be made not less than 180 MPa. Therefore, the tensile strength of the aluminum alloy wire is improved, and the elongation is not less than 3.0%, thereby improving the breaking force performance of the aluminum alloy wire, and the residual rate of tensile strength (230 °C) is not less than 92%. Therefore, the heat resistance performance of the aluminum alloy wire is improved. Therefore, through the above tests, it is verified that the two-stage aging strengthening method provided by the embodiment of the invention can improve the tensile strength and heat resistance performance of the aluminum alloy wire.

[0060] Thus, for the two-stage aging strengthening method of the aluminum alloy wire provided by the embodiment of the present invention, by raising the temperature of the made aluminum alloy wire to the primary aging temperature T1 and keeping it for the primary aging duration S1, the primary aging treatment of the aluminum alloy wire can be completed. By raising the temperature of the aluminum alloy wire to the secondary aging temperature T2 and keeping it for the secondary aging duration S2, the secondary aging treatment of the aluminum alloy wire can be completed; after cooling the aluminum alloy wire, the two-stage aging strengthening of the aluminum alloy wire is completed. After verification by the inventor, by making 175 °C ≤ T1 ≤ 185 °C, 5.5 h ≤ S1 ≤ 6.5 h, 195 °C ≤ T2 ≤ 205 °C, 5.5 h ≤ S2 ≤ 6.5 h, compared with the single-stage aging and the aluminum alloy wire without aging treatment, the tensile strength and heat resistance performance of the aluminum alloy wire after two-stage aging strengthening can be improved. Therefore, when using this aluminum alloy wire as the aluminum stranded wire of the overhead transmission line, the overall tensile strength and heat resistance performance of the overhead transmission line can be improved, thereby improving the phenomenon of increased sag and reduced breaking strength when the overhead transmission line is heated.

[0061] Example 2:

[0062] The embodiment of the present invention also provides an aluminum alloy wire, which is obtained by treating with the two-stage aging strengthening method in Example 1.

[0063] Exemplarily, the aluminum alloy wire is used in the overhead transmission line.

[0064] Based on the beneficial effects brought by the two-stage aging strengthening method in Example 1, the tensile strength of this aluminum alloy wire is not less than 180 MPa, the residual rate of tensile strength (230 °C) is not less than 92%, and the conductivity is not less than 60.5% IACS. That is, this aluminum alloy wire has good tensile strength and heat resistance performance, meeting the high requirements of the transmission line for materials.

[0065] Example 3:

[0066] Such as Figure 2 and Figure 3As shown in the figure, an embodiment of the present invention further provides an overhead transmission conductor for the field of power transmission. The overhead transmission conductor includes a load-bearing part and a conductive part. The load-bearing part is formed by concentric stranding of multiple load-bearing single wires 3. The conductive part is formed by stranding multiple conductive single wires 4 on the outer circumferential surface of the load-bearing part; the conductive single wire 4 adopts the aluminum alloy wire in Embodiment 2.

[0067] Exemplarily, the load-bearing part is mainly used to bear the tensile force in the overhead transmission conductor, and the conductive part is mainly used to transmit electricity.

[0068] Exemplarily, the cross-sectional shape of the load-bearing single wire 3 is circular, which can reduce the processing difficulty of the load-bearing single wire 3. The number of load-bearing single wires 3 can be set according to the tensile performance requirements of the overhead transmission conductor. For example, Figure 2 and Figure 3 in [specific cases], the number of load-bearing single wires 3 is six; or, the number of load-bearing single wires 3 can also be set to eight, ten, etc.

[0069] In some examples, the load-bearing single wire 3 is a galvanized steel strand, and the tensile strength of the load-bearing single wire 3 is greater than or equal to 1500 MPa.

[0070] Exemplarily, the tensile strength of the load-bearing single wire 3 can be 1500 MPa, 1790 MPa, 1900 MPa, etc.

[0071] Exemplarily, the load-bearing single wire 3 can be the G4A type extra-high strength load-bearing galvanized steel wire in the prior art, its cross-sectional diameter is 2.52 mm, and the tensile strength of a single load-bearing single wire 3 is 1790 MPa. As Figure 2 shown, at this time, the total cross-sectional area of the load-bearing part formed by six load-bearing single wires 3 is 30 mm 2 .

[0072] Or, the load-bearing single wire 3 can be the G5A type extra-high strength load-bearing galvanized steel wire in the prior art, its cross-sectional diameter is 2.81 mm, and the tensile strength of a single load-bearing single wire 3 is 1900 MPa. As Figure 2 shown, at this time, the total cross-sectional area of the load-bearing part formed by six load-bearing single wires 3 is 45 mm 2 .

[0073] Multiple conductive single wires 4 can be stranded on the outer circumferential surface of the load-bearing part to form a single-layer structure, or can form a multi-layer structure. The number of each layer of multiple conductive single wires 4 is determined according to the outer dimension of each conductive single wire 4 and the dimension of the overhead transmission conductor.

[0074] The conductive single wire 4 uses the aluminum alloy wire in Embodiment 2. Therefore, compared with the conductive single wire 4 in the prior art, the conductive single wire 4 in the embodiment of the present invention has better tensile strength and heat resistance, thereby improving the overall tensile strength and heat resistance of the overhead transmission line, and being able to withstand greater tensile force during icing, reducing the risk of the overhead transmission line breaking. Moreover, after the heat resistance of the overhead transmission line is improved, the residual rate of the tensile strength of the overhead transmission line at high temperature (for example, 150 °C) is relatively high. Therefore, the overhead transmission line also has a relatively high tensile strength at high temperature, so that the daily operating temperature of the overhead transmission line can be increased (for example, increased to 150 °C), thereby reducing the risk of icing of the overhead transmission line in low-temperature and high-humidity environments; further, the short-term (for example, less than ten minutes) operating temperature of the overhead transmission line can also be increased, for example, the short-term operating temperature of the overhead transmission line can be increased to 180 °C, thereby increasing the short-term overload capacity of the overhead transmission line and being able to perform current heating for de-icing in the case of icing that has already occurred.

[0075] Through the above settings, the overall tensile strength and heat resistance of the overhead transmission line can be improved, and the safety during the daily operation of the overhead transmission line can be improved. Further, the multi-layer stranded structure also improves the flexibility and anti-wind vibration ability of the overhead transmission line.

[0076] In some embodiments, the material of the conductive single wire 4 is an 8000 series aluminum-zirconium alloy, where the zirconium content is 0.1% - 0.2%; the tensile strength of the conductive single wire is greater than or equal to 180 MPa, the heat resistance of the conductive single wire 4 is greater than or equal to 92%, and the conductivity of the conductive single wire 4 is greater than or equal to 60.5% IACS.

[0077] The 8000 series aluminum-zirconium alloy has high tensile strength and good high-temperature stability itself (when serving for a long time at 200 - 250 °C, the attenuation rate of the tensile strength of the aluminum-zirconium alloy is less than 10%).

[0078] Through the above settings, on the basis of the high-temperature resistance performance of the conductive single wire 4 itself, the tensile strength and heat resistance of the conductive single wire 4 can be further improved by performing double-stage aging strengthening on the conductive single wire 4, thereby further improving the overall tensile strength and heat resistance of the overhead transmission line.

[0079] In some embodiments, the operating temperature of the overhead transmission line is T3, and 145 °C ≤ T3 ≤ 155 °C.

[0080] The operating temperature T3 of the overhead transmission line is the temperature of the overhead transmission line during daily operation.

[0081] Exemplarily, the operating temperature T3 of the overhead transmission line can be 145 °C, 150 °C or 155 °C, etc.

[0082] Compared with the daily operating temperature of 70 °C in the prior art, the operating temperature T3 of the overhead transmission line in the embodiments of the present invention is higher. Therefore, when encountering harsh environments of low temperature and high humidity, the overhead transmission line in the embodiments of the present invention is less likely to ice, thereby improving the anti-icing ability of the overhead transmission line.

[0083] In some embodiments, as Figure 2 and Figure 3 shown, multiple conductive single wires 4 are spliced and stranded in multiple layers along the circumferential direction of the load-bearing part in sequence to form a conductive part.

[0084] Exemplarily, the number of layers of the multiple conductive single wires 4 can be two layers, three layers, etc. The outer conductive single wires 4 are stranded closely against the inner conductive single wires 4 to reduce the gap between the conductive single wires 4 in each layer, make the overhead transmission line more dense, and avoid ice formation after rainwater accumulates in the overhead transmission line.

[0085] By arranging multiple layers of conductive single wires 4, the total cross-sectional area of the conductive part can be increased, thereby improving the conductivity of the conductive part, improving the conductivity of the overhead transmission line, and reducing the loss during power transmission of the overhead transmission line.

[0086] In some embodiments, as Figure 2 shown, the cross-section of the conductive single wire 4 is all in a T shape.

[0087] As Figure 2 shown, the length of the outer side of the cross-section of each conductive single wire 4 is greater than the length of the corresponding inner side. Therefore, after multiple conductive single wires 4 are stranded on the outer circumferential surface of the load-bearing part to form a ring, adjacent conductive single wires 4 can be in close contact, thereby reducing the gap between adjacent conductive single wires 4, avoiding ice formation due to rainwater accumulation in the gap between adjacent conductive single wires 4, improving the anti-icing ability of the overhead transmission line, and reducing the pitch grooves on the surface of the overhead transmission line, improving the smoothness of the overhead transmission line, and avoiding the attachment of rain and snow, further improving the anti-icing ability of the overhead transmission line.

[0088] In some embodiments, as Figure 3 shown, among any two adjacent layers of conductive single wires 4, the cross-section of the conductive single wires 4 in one layer is in a Z shape, and the cross-section of the conductive single wires 4 in the other layer is in an S shape.

[0089] As Figure 3 shown, the cross-section of the outermost conductive single wire 4 is in an S shape, and the cross-section of the adjacent second outermost conductive single wire 4 is in a Z shape. In each layer of conductive single wires 4, two adjacent conductive single wires 4 are spliced in sequence.

[0090] Through the above settings, each layer of conductive single wires 4 can be more firmly hinged, reducing the risk of deformation of the overhead transmission line conductor in the cross-section. The above settings can also make the adjacent conductive single wires 4 of each layer of conductive single wires 4 in close contact, thereby reducing the gap between adjacent conductive single wires 4, preventing rainwater from accumulating and freezing in the gap between adjacent conductive single wires 4, improving the anti-icing ability of the overhead transmission line conductor, and reducing the pitch grooves on the surface of the overhead transmission line conductor, improving the smoothness of the overhead transmission line conductor, preventing rain and snow from adhering, and further improving the anti-icing ability of the overhead transmission line conductor.

[0091] Currently, the icing monitoring of overhead transmission line conductors mainly relies on manual inspections or video monitoring, and it is impossible to obtain key parameters such as the temperature, ice layer thickness, and stress of the overhead transmission line conductor in real time, resulting in a lag in the ice melting decision-making, which is likely to lead to accidents such as wire breakage and pole collapse, severely damaging the power transmission system.

[0092] Based on this, in some embodiments, as Figure 2 and Figure 3 shown, the overhead transmission line conductor further includes a sensing optical fiber 1 and an armored layer 2. The sensing optical fiber 1 is arranged in the area surrounded by multiple load-bearing single wires 3. The sensing optical fiber 1 is connected to an external distributed optical fiber sensor, and the distributed optical fiber sensor is used to monitor the operating temperature and stress changes of the overhead transmission line conductor through the sensing optical fiber 1, so as to judge whether there is icing on the overhead transmission line conductor according to the operating temperature and stress changes of the overhead transmission line conductor. The armored layer 2 is arranged between the sensing optical fiber 1 and the inner circumferential surface of the load-bearing part, and is used to protect the sensing optical fiber 1.

[0093] The distributed optical fiber sensor is a sensor that uses distributed optical fiber detection technology in the prior art to measure or monitor the spatial distribution and time-varying information along the optical fiber transmission path, and can receive external signal changes through the sensing optical fiber 1. The spatial resolution monitoring of the distributed optical fiber sensor can reach 1m to 5m, and the positioning accuracy is relatively high, which is suitable for the monitoring of temperature / stress changes of long lines.

[0094] Exemplarily, the distributed optical fiber sensor can be a distributed optical fiber sensor with the model number DTS-8000L produced by Suzhou Tuoce Instrument and Equipment Co., Ltd.

[0095] Exemplarily, as Figure 2 and Figure 3 shown, the cross-sectional shape of multiple load-bearing single wires 3 is roughly annular, and the sensing optical fiber 1 is arranged inside the above-mentioned ring.

[0096] Exemplarily, the number of sensing optical fibers 1 can be one group or multiple groups, and the type of the sensing optical fiber 1 is multimode optical fiber.

[0097] By setting the sensing optical fiber 1, it can cooperate with an external distributed optical fiber sensor to quickly obtain and process the icing condition on the overhead transmission line, thereby improving the processing speed of the icing on the overhead transmission line, avoiding accidents such as wire breakage and pole collapse caused by the continuous increase of icing on the overhead transmission line, and preventing the power transmission system from being severely damaged.

[0098] Exemplarily, the armor layer 2 is made of a stainless steel tube, a carbon nanotube, or the like.

[0099] Exemplarily, an epoxy resin coating is further provided on the inner wall surface of the carbon nanotube to improve the flexibility of the inner wall surface of the carbon nanotube and prevent the sensing optical fiber 1 from being damaged by colliding with the inner wall of the carbon nanotube.

[0100] In this case, the manufacturing process of the overhead transmission line is as follows: the sensing optical fiber 1 is combined inside the armor layer 2, and then multiple load-bearing single wires 3 are arranged evenly and closely around the armor layer 2.

[0101] Through the above settings, it is possible to prevent the sensing optical fiber 1 from being damaged or open-circuited during the forming and stranding process of the overhead transmission line, which affects the transmission efficiency and quality of the signal in the sensing optical fiber 1. In addition, the armor layer 2 can also improve the overall tensile performance of the overhead transmission line.

[0102] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principle of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A two-stage aging strengthening method for aluminum alloy conductors, characterized in that, Comprising: Raise the temperature of the fabricated aluminum alloy wire to the primary aging temperature T1 and hold for the primary aging duration S1; wherein, 175°C ≤ T1 ≤ 185°C, 5.5 h ≤ S1 ≤ 6.5 h; Then raise the temperature of the aluminum alloy wire to the secondary aging temperature T2 and hold for the secondary aging duration S2; wherein, 195°C ≤ T2 ≤ 205°C, 5.5 h ≤ S2 ≤ 6.5 h; Then cool the aluminum alloy wire.

2. The double-stage aging strengthening method of the aluminum alloy wire according to claim 1, characterized in that The cooling of the aluminum alloy wire specifically is: placing the aluminum alloy wire in the air for natural cooling until the cooling duration of the aluminum alloy wire is S3, S3 ≥ 8 h.

3. An aluminum alloy wire, characterized in that, Obtained by using the two-stage aging strengthening method described in claim 1 or 2.

4. An overhead transmission line conductor, characterized in that, Comprising: A load-bearing part formed by concentric stranding of multiple load-bearing single wires (3); And, A conductive part formed by stranding multiple conductive single wires (4) on the outer circumferential surface of the load-bearing part; the conductive single wire (4) uses the aluminum alloy wire described in claim 3.

5. The overhead transmission conductor according to claim 4, wherein The material of the conductive single wire (4) is an 8000-series aluminum-zirconium alloy, where the zirconium content is 0.1% - 0.2%; the tensile strength of the conductive single wire is greater than or equal to 180 MPa, the heat resistance of the conductive single wire (4) is greater than or equal to 92%, and the conductivity of the conductive single wire (4) is greater than or equal to 60.5% IACS.

6. The overhead transmission conductor according to claim 5, wherein The operating temperature of the overhead transmission wire is T3, 145°C ≤ T3 ≤ 155°C.

7. The overhead transmission wire according to claim 4, wherein Multiple conductive single wires (4) are spliced and stranded in multiple layers along the circumferential direction of the load-bearing part in sequence to form the conductive part.

8. The overhead transmission wire according to claim 7, wherein The cross-section of the conductive single wire (4) is all in a T shape; or, among any adjacent two layers of the conductive single wires (4), the cross-section of one layer of the conductive single wire (4) is in a Z shape and the cross-section of the other layer of the conductive single wire (4) is in an S shape.

9. The overhead transmission conductor according to claim 4, characterized in that The load-bearing single wire (3) is a galvanized steel strand, and the tensile strength of the load-bearing single wire (3) is greater than or equal to 1500 MPa.

10. The overhead transmission conductor according to claim 4, characterized in that, Further comprising: A sensing optical fiber (1) disposed within the area enclosed by the multiple load-bearing single wires (3); The sensing optical fiber (1) is connected to an external distributed optical fiber sensor, and the distributed optical fiber sensor is used to monitor the operating temperature and stress changes of the overhead transmission wire through the sensing optical fiber (1) to determine whether there is icing on the overhead transmission wire according to the operating temperature and stress changes of the overhead transmission wire; And, An armor layer (2) disposed between the sensing optical fiber (1) and the inner circumferential surface of the load-bearing part for protecting the sensing optical fiber (1).

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