Main Factors affecting overall tensile properties of overhead conductors
With the continuous upgrading of the power system, various new products have emerged, such as steel-reinforced aluminum stranded wire, aluminum-clad steel-clad aluminum stranded wire, aluminum-clad steel-clad aluminum alloy stranded wire, aluminum alloy stranded wire, aluminum alloy core aluminum stranded wire, aluminum-clad steel core heat-resistant aluminum alloy stranded wire, etc.
However, the overall tensile performance has always been a major issue perplexing the design of overhead stranded wire products.
The rated breaking force of the conductor is calculated according to the strength of all aluminum single wires and reinforcements.
However, the actual tensile breaking force will deviate from the real calculated value to a certain extent, and the main reason is that the strength of each single line is not fully utilized.
Therefore, when designing products, we should not only meet their minimum strength requirements, but also consider how to dig out the strength of each single line.
Not only is it a full use of the material, but the overall performance of The Wire will also be greatly improved. We can start from the following aspects.
First, 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 lines, and the bearing degree of aluminum single lines with different strengths to stress is also different.
When these single lines with large strength deviation are stranded 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, a single line with high strength cannot play its role.
Therefore, the strength range is an important parameter to test the utilization rate of mechanical properties.
Second, adjust the size of elongation and pitch diameter ratio from the elongation and pitch diameter 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 tensile breaking force of aluminum clad steel core aluminum stranded wire is easy to appear unqualified phenomenon.
The main reason is that the elongation of aluminum clad steel is too small. The utilization rate of mechanical properties of aluminum wire is too low.
When the aluminum wire is twisted, the smaller the pitch, the better its ductility. The higher the elongation requirement of steel wire is. The elongation of aluminum clad steel wire is 1. About 0, aluminum wire is also 1.
About 0, plus the stretching amount of stranded pitch, the elongation of steel wire is far from enough.
Therefore, the wire design for aluminum-clad steel wire can appropriately increase its pitch-to-diameter ratio, reduce the gap in elongation between aluminum-clad steel wire and aluminum wire, and give more play to the mechanical properties of aluminum wire.
In a word, the elongation of aluminum wire, because the pitch elongation = the elongation of steel wire.
Third, starting from the arrangement structure, the single line with larger elongation is arranged in the outermost layer.
The test proves that the single line fracture is mostly in the outermost layer fracture.
The elongation of the outermost layer is also a key factor affecting the overall tensile breaking force.
When the single line strength is certain, the higher the elongation, the higher the single line mechanical properties of high strength can be used to the maximum 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. Here is just a concept, focus on practice.
In short, in the design of the product, the ultimate goal is in the wire elongation to 1%, all single wire can play to the best effect, so that the overall performance of The Wire will be greatly improved.