Dazheng National Standard Galvanized Hose Support Expansion Wire LGKK-1400 Substation Transmission Transformer

Description :

　　Dazheng National Standard Galvanized Hose Support Expansion Wire LGKK-1400 Substation Transmission Transformer

　　Purpose of the extension wire:

　　Expanded conductors can be divided into two categories based on their usage: one type is used in substations, and the other type is used in transmission lines. In order to reduce sag and tower height, the tension to weight ratio of the expanded diameter conductor used in transmission lines should be equivalent to that of steel cored aluminum stranded wire. Therefore, this type of expanded diameter conductor must have a steel core. Because the expansion wire used in transmission lines must be tensioned, and after passing through several pulleys during the tensioning process, it is required to have no jumping or loosening of strands. Therefore, the stability of the structure of this expansion wire is higher, and the expansion ratio of this expansion wire should not be too large. The main function of using expanded diameter conductors in substations is to direct current from transformers to transmission lines, usually only a few tens of meters away, without considering issues such as sag and tension. Due to the fact that the number of splits in substation busbars is usually smaller than the number of splits in line conductors, and given similar environmental limits for electromagnetic noise, it is required that the outer diameter of substation busbars be much larger than that of line conductors. Therefore, the characteristic of this type of expanded diameter conductor is that it has no steel core, but the expansion diameter is relatively large.

　　Classified by structural characteristics

　　According to the structural characteristics of expanded diameter wires, they are divided into four categories: large inner diameter aluminum tube supported expanded diameter wires, small inner diameter aluminum tube filled expanded diameter wires, sparse twisted expanded diameter wires, and high-density polyethylene supported expanded diameter wires.

　　Small inner diameter aluminum tube filled expanded diameter wire. This type of expanded diameter wire is made by twisting multiple small inner diameter aluminum tubes (instead of aluminum single wires) outside the steel core. Large inner diameter aluminum tube supported expanded diameter wire. This type of expanded diameter wire has no steel core and is made by twisting multiple layers of aluminum single wires on a large inner diameter aluminum tube. Sparse twisted expanded diameter wire, high-density polyethylene supported expanded diameter wire.

　　Characteristics of Radial Conductors

　　Expanded diameter conductor refers to a conductor with an enlarged outer diameter compared to a concentric twisted hollow conductor with a similar cross-section. There are many types of expanded diameter conductors with significant structural differences, but they can be divided into two categories based on their use: for substations and for transmission lines.

　　Expanded diameter wires have the following characteristics:

　　(1) Compared with conventional wires of the same cross-section, the outer diameter of the expanded wire increases, the corona loss decreases, and the radio interference and audible noise derived from corona also decrease, effectively improving the electromagnetic environment and benefiting environmental protection.

　　(2) Compared with conventional wires with the same outer diameter, the aluminum cross-section of the expanded wire is reduced, saving aluminum material and reducing the weight of the wire. This not only reduces the amount of wire used, but also reduces the steel consumption of the tower due to the decrease in tower load, thereby reducing the investment in transmission line engineering.

　　(3) Compared with conventional wires with the same outer diameter, expanded diameter wires have the same corona characteristics due to the same outer diameter of the wires.

　　Selection of Expanding Method

　　Determine the wire cross-section based on the conveying capacity, determine the outer diameter of the wire based on electromagnetic environment control indicators, and consider expanding the diameter after the wire cross-section and outer diameter are clear. When choosing the expansion method, the first consideration should be the economy. Based on preliminary calculations, the cost of the sparse twisted expanded diameter wire is lower than that of the high-density polyethylene supported expanded diameter wire, and the project cost is lower if the sag characteristics are better, which shows that the investment for sparse twisted expanded diameter wire of the same specification is lower. Secondly, the stability of the structure should be considered.

　　For sparse twisted expanded diameter conductors, the expansion ratio of 310K400 is 1.29, and the expansion ratio of 400K500 is 1.20. Engineering practice has proven that its structure is stable; The expansion ratio of 630K720 is 1.14, and the test proves that its structure is stable. This wire underwent engineering deployment tests on the Yongdeng Baiyin 750 kV transmission line in March 2009. However, the expansion ratio of 500K630 is 1.26630K800, 1.27720K900 is 1.25, and analysis suggests that all three structures are unstable. It can be seen that with the increase of conductive cross-section, the expansion ratio shows a downward trend while maintaining structural stability. Therefore, the expansion ratio alone cannot be used to select the expansion method. In actual transmission projects, when choosing the wire expansion method, the size of the conductive cross-section needs to be taken into account.

　　In short, the expansion method should prioritize the sparse twisted type but also ensure the stability of the wire structure.

　　Dazheng National Standard Galvanized Hose Support Expansion Wire LGKK-1400 Substation Transmission Transformer

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