How to calculate overhead cable size?

Views:0     Author:Site Editor     Publish Time: 2021-03-16      Origin:Site

With the continuous development of the power industry, the application of insulated overhead cable has gradually become more extensive. Factors such as length and weight are an important part of considering the use of aerial bundle overhead cable. In order to standardize the aluminum core overhead cable construction technology, high engineering quality, and ensure construction safety, it is necessary to study and discuss its dimensions.

 

Here is the content list:

  • How to define the structure of overhead cable in the power industry?

  • What is the differentiation between distinct specifications of overhead cables?

  • Why does it make sense to study the length of overhead cable?

 

How to define the structure of overhead cable in the power industry?

Traditional high-voltage power transmission methods have their own advantages and disadvantages in their scope of application. In order to meet the requirements of urbanization and development, a new high-voltage power transmission method of overhead cable has come out.

Overhead cable is an overhead wire equipped with an insulating layer and a protective sheath. It is a special cable manufactured by a production process similar to that of a cross-linked cable. Overhead cables are almost single-core, but they can be divided into many kinds according to their different structures.

 

What is the differentiation between distinct specifications of overhead cables?

Overhead cable does not directly hang ordinary oil-paper insulated cables or cross-linked insulated cables on overhead poles, but uses a special cable that is similar to the production process of cross-linked cables.

Most of overhead cables are designed to be single-core, whcih can be divided into distinct kinds according to their different structures, such as hard aluminum, copper and aluminum alloy wire structure, core support structure and so on.

  • Duralumin wire structure

The overhead cable of duralumin wire structure is light in weight and moderate in tension. This kind is easy to bend, easy to install, and the project cost is low, so it can be installed on existing poles and towers. Generally, this kind of overhead cable is used in renovation or new construction projects.

  • Copper & aluminum alloy wire structure

The overhead cable of the hard-drawn copper wire structure is heavier, but the pulling force is large and the ability to resist external forces is strong, and the cable can continue to be energized even when the tower is broken.

The overhead cable of aluminum alloy wire structure is light in weight and large in tension, and is mainly used in large-span pole tower systems with a span of more than 100 meters.

  • Core support structure

The metal core support structure is commonly used in low voltage systems, and the span is also large. The core support wire is separated from the three insulated phase wires with a square insulator, which can be used as a lightning protection wire. The biggest advantage of this overhead cable is that the arc sag is small.

 

Why does it make sense to study the length of overhead cable?

The length of the overhead cable does not have much impact on the current to a certain extent, and is usually negligible. However, when the load is constant, the longer the overhead cable, the greater its resistance.

Because the current carrying capacity of the overhead cable is related to the cross-section, and also related to its material, model, laying method, and ambient temperature, there are many influencing factors and the calculation is more complicated.

Although under normal circumstances, the length of the overhead cable has little effect on the current to a certain extent, the length will still affect other aspects because the heat generated by the overhead cable is proportional to the resistance.

This means that the longer the insulated overhead cable of the same specification is used, the more heat will be generated, and this heat cannot be dissipated in time, which will accelerate the aging.

The aging of the overhead cable will cause a series of safety problems. Especially when the overhead cable insulation falls off, it may cause electric leakage, short circuit and other accidents, which will bring unimaginable consequences for the life safety of residents.

 

Therefore, the length of the aerial bundle overhead cable needs to be judged according to the on-site installation situation, and also depends on the installation direction and actual needs. It is particularly important to choose a reputable and strong aluminum core overhead cable manufacturer. People’s Cable Group Co.,Ltd. has passed many international quality system certifications, etc., with complete product specifications and reasonable prices. We look forward to your consultation and visit.


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