Main factors affecting the overall tensile performance of overhead conductor
With the continuous upgrading of power system, various new products have emerged, such as steel core aluminum stranded conductor, aluminium-coated steel core aluminum stranded conductor, aluminium-coated steel core aluminum alloy sterepsinema, aluminum alloy sterepsinema, aluminum alloy core aluminum stranded conductor, aluminium-coated steel core heat-resistant aluminum alloy sterepsinema, etc. However, the overall tensile performance has always been a major issue perplexing the design of overhead stranded wire products.
The rated tensile breaking force of the conductor is calculated based on the strength of all aluminum single wires and reinforcement part. However, the actual breaking force will have a certain deviation from the actual calculated value. The main reason is that the strength of each single line is not fully utilized. Therefore, when designing products, we should not only meet the minimum strength requirements, but also consider how to dig out the strength of each single line. Not only is the material fully utilized, but also the overall performance of the conductor will be greatly improved. We can start from the following aspects.
1. starting from the strength, adjust the uniformity of each single line.
According to the strength of each single line, the bearing degree of stress is also different. Just as the tension sensor has the best stretching range, exceeding its range will not only damage the equipment, but also cause data deviation. The same is true for aluminum single wire, and the stress bearing degree of aluminum single wire with different strength is also different. When these single lines with large strength deviation are twisted together, the stress is evenly distributed to each single line, and the single line with small strength will break in advance due to insufficient bearing degree, however, the strong single line cannot play its role. Therefore, the intensity range is an important parameter for testing mechanical performance utilization rate.
2. Adjust the elongation and lay ratio from the perspective of elongation and lay ratio.
The elongation of steel wire also has a great influence on the overall tensile properties. A large number of experiments have proved that the overall breaking force of aluminum-clad steel-core aluminum strand is prone to unqualified phenomenon. The main reason is that the elongation of aluminium-coated steel is too small. Aluminum steel the utilization rate of mechanical properties is too low. When aluminum steel is twisted, the smaller the pitch, the better its ductility. The higher the elongation requirement for steel wire is. However, the elongation of aluminum-clad steel wire is about 1.0, and that of aluminum steel is also about 1.0. With the expansion of stranding pitch, the elongation of steel wire is far from enough. Therefore, the conductor design for aluminum-clad steel wire can appropriately increase its lay ratio, reduce the gap between aluminum-clad steel wire and aluminum steel elongation, and exert more mechanical properties of aluminum steel. In short, aluminum steel elongation + pitch elongation = steel wire elongation.
3. starting from the arrangement structure, the single line with larger elongation is arranged in the outermost layer.
The test proves that most single-line faults are in the outermost layer. The elongation of the outermost layer is also the key factor affecting the overall tensile breaking force. When the strength of the single line is constant, the higher the elongation, the mechanical properties of the high strength single line can play a role to the greatest extent.
At present, the performance of most wires has not been fully developed, and the margin is very large. This process is a long-term exploration process, which requires a lot of experiments and data analysis. This is just a concept, focus on practice. In short, when designing the product, the ultimate goal is that when the wire is extended to 1%, all single wires can achieve the best effect, so that the overall performance of The Wire will be greatly improved.