Views:202 Author:Site Editor Publish Time: 2021-07-20 Origin:Site
The conductor and lightning conductor of overhead lines are erected in the field and operate in the open air all year round, which not only causes the line to bear its own tension, but also is affected by various meteorological conditions, as well as sometimes eroded by various chemical gases and impurities in the atmosphere. Therefore, in addition to fine electrical conductivity, the conductor and lightning conductor also require high mechanical strength. In addition, it is necessary to use the remote overhead line fault passage indicator and other overhead line fault indicators to detect faults at all times. Today, we will introduce the classification of overhead lines.
Copper conductor has excellent conductivity, high mechanical strength and strong corrosion resistance. The density of copper is 9.8g/cm³, which is an ideal conductor material. However, copper is widely used in industry, with few resources and high prices. Therefore, copper wire is generally only used in distribution lines in areas with high current density or serious chemical corrosion.
The electrical conductivity and mechanical strength of aluminum conductor are inferior to that of copper conductor. Compared with copper, the conductivity of aluminum is 1.6 times smaller than that of copper. The mechanical strength and chemical corrosion resistance of aluminum are also poor. But the quality of aluminum is small, the density of aluminum is 2.7g/mm3, and the storage of aluminum is high and the price is low. Therefore, aluminum is also an ideal conductor material. The nature of aluminum determines that aluminum wire is generally used in overhead distribution lines with small span, but it is not suitable to use aluminum wire in coastal areas or near chemical plants. Even the overhead distribution lines with small span need to be equipped with reliable cable fault passage indicators and accurate overhead line indicator faults.
ACSR stranded wire
In order to make full use of the advantages of aluminum and steel to make up for their shortcomings, the steel cored aluminum strand is made by combining them. ACSR has high mechanical strength. The mechanical stress is shared by the steel core wire and aluminum core, and the skin effect of AC can make the current in the steel core wire almost zero, and the current is basically conducted by aluminum wire. Therefore, the conductivity and mechanical properties of ACSR are relatively good, which is suitable for large span overhead power lines. It is very important to adopt an accurate cable fault indicator monitoring system and advanced cable fault passage indicators for large span overhead power lines.
Anticorrosive steel reinforced aluminum stranded wire (LGJF)
LGJF, its structure and mechanical properties and electrical properties are the same as common aluminum conductors. It can be divided into light anti-corrosion type (only coating preservative on steel core), medium anti-corrosion type (only coating preservative on steel core and inner aluminum wire) and heavy anti-corrosion type (coating preservative on steel core and inner and outer aluminum wire). This kind of wire is used in coastal areas and areas with corrosive gases.
Steel core rare earth aluminum strand (LGJX)
LGJX is a new energy saving product jointly developed by Guangzhou Nonferrous Metals Research Institute and Guangdong Taishan cable factory in the early 1980s. It is characterized by adding a small amount of rare earth metals into industrial pure aluminum to make aluminum wires under certain process conditions. It has been tested by Shanghai Cable Research Institute and Electric Power Construction Research Institute of the Ministry of power industry. The electrical conductivity and mechanical properties of the system are up to IEC standard.
Steel reinforced aluminum alloy stranded wire (HLGJ)
HLGJ is a circular single wire drawn from aluminum, magnesium and silicon alloy. The multi strand single wire is twisted around the inner steel core. The tensile strength of HLGJ is about 40% higher than that of common ACSR, and its conductivity and quality are close to that of aluminum wire, so it is suitable for large crossing places.
Aluminum clad steel strand
GLJ, with single strand steel wire as core and aluminum layer as outer layer, is made into single strand or multi strand stranded wire. The thickness of aluminum layer and diameter of steel core can be manufactured through negotiation with the manufacturer according to the actual needs of the project. The price is high and the conductivity is poor. It is suitable for high frequency communication in the large span and overhead section. Because of its high-price, it is necessary to equip the GLJ with the digital overhead line fault indicator for remote monitoring faults.
Galvanized steel strand
The electrical conductivity of galvanized steel strand is very poor, but the mechanical strength of steel strand is high. Due to the poor conductivity of steel strand, it is not suitable to be used as a power line conductor. It is mainly used for lightning conductor, grounding downlead and stay wire of overhead power line, as well as load-bearing cable of insulated conductor and communication line.
The above are some classifications of overhead lines. In order to be able to discover your overhead circuit failure in time, we recommend the CHAOBO overhead line fault indicator to you. In addition to the overhead line fault indicator, our company also has some products such as the short circuit and earth fault indicator. If you are interested, you can go to our website to know more: https://www.fault-indicator.com/products.html