Full-tension pre-twisted wire repairing method for damaged steel wire of overhead power transmission steel-cored aluminum strand

Abstract

The invention relates to the technical field of power line maintenance, in particular to a full-tension pre-twisted wire repairing method for a damaged steel wire of an overhead power transmission steel-cored aluminum strand. Comprising the following steps: (1) preparing repairing materials and tools; (2) performing damage assessment; (3) tension pre-tightening; (4) layered winding; (5) releasing tension; the tension self-adjusting clamp and the layered winding process are adopted, specifically, 8-12 kN pre-tightening force application, three-layer pre-twisted wire progressive winding and tension gradient release are included, and + / -1N tension precision control is achieved through linkage control of a pressure sensor and a hydraulic mechanism of the tension self-adjusting clamp; and key technical means such as a method for matching the 15-degree spiral dip angle of the aluminum alloy steel wire with the wire torsion angle are adopted, so that the repairing efficiency is greatly improved, the repairing strength is improved, the safety of operators is guaranteed, and the maintenance cost and cost are reduced.

Description

Technical Field

[0001] This invention relates to the field of power line maintenance technology, specifically to a method for repairing damaged steel wires in overhead transmission steel-cored aluminum stranded wires using full-tension pre-twisting. Background Technology

[0002] Current methods for repairing damaged steel wires in overhead power transmission steel-cored aluminum stranded wires have the following problems: (1) Defects of the crimping method: It requires a power outage of 4-6 hours, the use of crimping tubes and large crimping tools, and the operation is complicated (12 processes such as cleaning, marking, crimping, etc.). Moreover, the splicing strength is only 80% of the original conductor, and it is easy to cause secondary damage due to stress concentration during crimping.

[0003] (2) Limitations of traditional pre-twisted wire: Existing pre-twisted wire winding methods rely on manual alignment marks, which are difficult to operate accurately in complex terrains such as mountains. Furthermore, they do not take into account the dynamic tension of the conductor during operation, and there is a risk of loosening after repair.

[0004] (3) Gaps in live-line work: Traditional methods cannot achieve live-line repair, and single-circuit operation is prone to large-scale power outages (such as a coal washing plant losing 600,000 yuan for 4 hours of single-circuit operation). Summary of the Invention

[0005] To achieve rapid repair of broken strands in steel-cored aluminum stranded wires under energized conditions, this invention provides a full-tension pre-twisted wire repair method for damaged steel wires in overhead power transmission steel-cored aluminum stranded wires. This method solves the problem of insufficient strength in traditional methods, shortens power outage time to within 1 hour, increases repair strength to more than 95% of the original conductor, overcomes the shortcomings of insufficient precision in manual operation under complex terrain, and achieves automated tension control.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a method for repairing damaged steel wires in overhead power transmission steel-cored aluminum stranded wires with full tension pre-twisted wires, comprising the following steps: (1) Prepare repair materials and tools Prepare repair materials and a tension self-adjusting fixture; the repair materials include steel core wire, aluminum alloy wire, and full-tension pre-twisted wire, the surface of which is treated with anti-slip texture; the tension self-adjusting fixture has a built-in pressure sensor and a micro hydraulic mechanism; (2) Damage assessment The location of the broken strand and the integrity of the steel core were detected by ultrasonic flaw detector to determine the scope of repair. (3) Tension pre-tightening The tension self-adjusting clamp is fixed on both sides of the broken strand, and the micro hydraulic mechanism automatically applies a preload of 15% of the rated tension of the steel wire conductor to compensate for the tension loss during repair. (4) Layered winding Inner layer: The steel core wire is wound in a two-way symmetrical manner with the center mark as the reference. The overlap of a single turn is ≥20mm and the winding tension is controlled at 5-8N·m. Middle layer: Aluminum alloy steel wire is spirally wound at a 15° angle, with a 1-2mm interval between each turn. The contact stress is monitored in real time by a pressure sensor of a tension self-adjusting fixture, with a threshold of 1.2MPa. Outer layer: The full tension pre-twisted yarn group adopts a three-stage progressive winding method, specifically, first fixing the middle pitch, and then extending to both ends to ensure that the surface flatness is ≤0.5mm; (5) Tension release After the repair is completed, the hydraulic mechanism gradually releases the tension at a rate of 2kN / s, so that the pre-twisted wire and the conductor form a cooperative force-bearing system.

[0007] As a further limitation of the technical solution of the present invention, the depth of the texture on the surface of the pre-twisted wire in step (1) after anti-slip texture treatment is 0.3-0.5mm.

[0008] As a further limitation of the technical solution of the present invention, the accuracy of the built-in pressure sensor in step (1) is ±1N.

[0009] As a further limitation of the technical solution of the present invention, the detection accuracy of the ultrasonic flaw detector in step (2) for detecting the broken strand location and the integrity of the steel core is ±0.1mm.

[0010] Compared with the prior art, the present invention has the following beneficial effects: Technological Innovations: The tension adaptive control algorithm of this invention automatically matches the preload parameters according to the conductor cross-section (120-185mm²), avoiding damage to the aluminum strands due to excessive tightness or loosening due to excessive looseness; Helical tilt angle compensation technology: the winding tilt angle of the middle layer aluminum alloy steel wire is matched with the conductor torsion angle (0.5-1° / m), eliminating fretting wear during operation.

[0011] Efficiency improvement: Repair time has been reduced from 6 hours using the traditional clamping method to 1.5 hours, and single-circuit operating losses have been reduced from 600,000 yuan to 150,000 yuan (taking a coal washing plant as an example).

[0012] Strength advantage: The tensile strength retention rate of the repaired conductor reaches 96.3% (92% for conventional pre-twisted wire), and it passes the vibration resistance test of GB / T2338-2014 (no loosening after 3 million vibrations).

[0013] Safety Guarantee: Supports live-line work on 10-35kV lines, avoiding the risk of power outages during pole climbing and reducing the probability of personnel injury or death by 80%.

[0014] Highly economical: The cost of a single repair is 0.6 million yuan (compared to 50,000 yuan for traditional methods), and the annual maintenance cost can be reduced by 494,000 yuan. Detailed Implementation

[0015] The present invention will be further described below with reference to specific embodiments. Example 1

[0016] A method for repairing damaged steel wires in overhead power transmission steel-cored aluminum stranded wires using full-tension pre-twisted strands includes the following steps: (1) Prepare repair materials and tools Prepare repair materials and a tension self-adjusting fixture; the repair materials include steel core wire, aluminum alloy wire, and full-tension pre-twisted wire, the surface of which is treated with anti-slip texture (texture depth 0.3-0.5mm); the tension self-adjusting fixture has a built-in pressure sensor (accuracy ±1N) and a micro hydraulic mechanism; (2) Damage assessment The location of the broken strand and the integrity of the steel core were detected by ultrasonic flaw detector (detection accuracy ±0.1mm) to determine the repair scope; (3) Tension pre-tightening The tension self-adjusting clamp is fixed on both sides of the broken strand, and the micro hydraulic mechanism automatically applies a pre-tightening force of 8-12kN (equivalent to 15% of the rated tension of the conductor) to compensate for the tension loss during repair. (4) Layered winding Inner layer: The steel core wire is wound using the center mark as a reference, and the "two-way symmetrical winding method" is adopted. The overlap of a single turn is ≥20mm, and the winding tension is controlled at 5-8N·m. Middle layer: Aluminum alloy steel wire is spirally wound at a 15° angle, with a 1-2mm interval between each turn. The contact stress is monitored in real time by a pressure sensor of a tension self-adjusting fixture, with a threshold of 1.2MPa. Outer layer: The full tension pre-twisted yarn group adopts a "three-stage progressive winding", which means first fixing the middle pitch and then extending to both ends to ensure that the surface flatness is ≤0.5mm; (5) Tension release After the repair is completed, the hydraulic mechanism gradually releases the tension at a rate of 2kN / s, so that the pre-twisted wire and the conductor form a cooperative force-bearing system.

[0017] This invention employs key technologies such as "tension self-adjusting fixture and layered winding process, specifically including 8-12kN pre-tightening force application, three-layer pre-twisted progressive winding and tension gradient release," "tension self-adjusting fixture pressure sensor and hydraulic mechanism linkage control to achieve ±1N tension accuracy control," and "matching method of 15° helical inclination angle of aluminum alloy steel wire and conductor torsion angle," which significantly improves repair efficiency, increases repair strength, ensures operator safety, and reduces maintenance costs.

Claims

1. A method for repairing damaged steel wires in overhead power transmission steel-cored aluminum stranded wires using full-tension pre-twisting, characterized in that, Includes the following steps: (1) Prepare repair materials and tools Prepare repair materials and tension-adjustable clamps; The repair materials include steel core wire, aluminum alloy steel wire, and full-tension pre-twisted wire, the surface of which is treated with anti-slip texture; the tension self-adjusting fixture has a built-in pressure sensor and a micro hydraulic mechanism. (2) Damage assessment The location of the broken strand and the integrity of the steel core were detected by ultrasonic flaw detector to determine the scope of repair. (3) Tension pre-tightening The tension self-adjusting clamp is fixed on both sides of the broken strand, and the micro hydraulic mechanism automatically applies a preload of 15% of the rated tension of the steel wire conductor to compensate for the tension loss during repair. (4) Layered winding Inner layer: The steel core wire is wound in a two-way symmetrical manner with the center mark as the reference. The overlap of a single turn is ≥20mm and the winding tension is controlled at 5-8N·m. Middle layer: Aluminum alloy steel wire is spirally wound at a 15° angle, with a 1-2mm interval between each turn. The contact stress is monitored in real time by a pressure sensor of a tension self-adjusting fixture, with a threshold of 1.2MPa. Outer layer: The full tension pre-twisted yarn group adopts a three-stage progressive winding method, specifically, first fixing the middle pitch, and then extending to both ends to ensure that the surface flatness is ≤0.5mm; (5) Tension release After the repair is completed, the hydraulic mechanism gradually releases the tension at a rate of 2kN / s, so that the pre-twisted wire and the conductor form a cooperative force-bearing system.

2. The method for repairing damaged steel wires in overhead power transmission steel-cored aluminum stranded wires under full tension pre-twisted wires according to claim 1, characterized in that, In step (1), the surface of the pre-twisted wire is treated with anti-slip texture, and the texture depth is 0.3-0.5mm.

3. The method for repairing damaged steel wires in overhead power transmission steel-cored aluminum stranded wires under full tension pre-twisted wires according to claim 1, characterized in that, The accuracy of the built-in pressure sensor in step (1) is ±1N.

4. The method for repairing damaged steel wires in overhead power transmission steel-cored aluminum stranded wires under full tension pre-twisted wires according to claim 1, characterized in that, In step (2), the ultrasonic flaw detector has a detection accuracy of ±0.1mm for detecting the location of the broken strand and the integrity of the steel core.