Armored power cable YJV22 * 50/70/95/120mm flame retardant

Armored power cable YJV22 * 50/70/95/120mm flame retardant

（1） The insulated power supply that can transmit large capacity electrical energy safely and reliably for a long time is called a "power cable".

Power cables are cables with conductors wrapped in insulating materials and various protective layers. Its main function is to transmit and distribute large capacity electrical energy in the power system, similar to overhead wires. The difference between power cables and overhead lines is that they can be laid in various environments, are safe and concealed, and are not affected by external climate change; And it can be maintained less and durable (generally required)40Years and above). But the structure of power cables is relatively complex, with multiple manufacturing processes, and the product price is tens of times higher than that of overhead wires; Therefore, it is generally applied in situations where overhead power lines are not suitable, such as transmission and distribution lines in cities, power introduction in industrial and mining enterprises, and main power lines in factory areas; And crossing rivers, railway stations, and underground tunnels. In fact, power lines are composed of overhead conductors and power cables. Overhead conductors focus on the transmission, transformation, and distribution of power sources, while power cables are mainly used for distribution and consumption. Therefore, the production of medium and low voltage power cables accounts for98%Above.

With the rapid improvement of China's economic level, the proportion of power cables in the power system is constantly increasing. The medium and low voltage overhead lines in the city center will gradually be replaced with concealed cable lines, while overhead insulated cables will be used in suburban and central towns.

（2） Power cables should have the following technical characteristics

1Can withstand high costs in the long termZhi *'s working voltageIt should have excellent electrical insulation performance, so power cables can be divided into low voltage according to the voltage level of use（1KV and below), medium voltage（6——35Kilovolts, high voltage（66——330Kilovolts, ultra-high voltage（500Kilovolts and above).

2It can transmit large currents (several hundred to several thousand amperes), so conductive wire cores with cross-sectional areas of several hundred to several thousand square millimeters are used. At the same time, it is required that the insulation and other materials used have excellent heat aging resistance, while the overall structure can maintain thermal balance.

3In order to adapt cables to various laying methods and usage environments (underground, underwater, trench, tunnel, vertical shaft), multiple combinations of protective layer structures must be adopted.

In fact, the high voltage insulation technology, high current transmission technology, structural balance, and protective layer structure that power cables rely on represent the academic level of these aspects in the field of electrical engineering.

Armored power cable YJV22 * 50/70/95/120mm flame retardant

（3） The process equipment for manufacturing power cables mainly includes stranding machines, insulation wrapping equipment, and cabling machines3——5Twisted insulated wire cores into cables, extruded inner and outer sheaths, and armored equipment (steel strip, steel wire armor). Among them, different insulation structures use different equipment, and the process technology requirements are *.

（4） Power cables are all used in the power system, so they are generally not classified into small categories, but are classified into series according to different insulation materials or structures.

The product series of power cables include:

1Due to the cheap price, good physical and mechanical properties, and simple extrusion process, polyvinyl chloride insulated power cables have average insulation performance. Therefore, it is widely used for manufacturing1Low voltage power cables of kilovolts and below are used for low-voltage distribution systems, with an annual output of over 100000 kilometers. If insulation materials with added voltage stabilizers are used, production is allowed6Kilovolt level cables.

2Cross linked polyethylene insulated power cables have good electrical properties, mechanical properties, and heat resistance due to the fact that polyethylene is a plastic with electrical insulation properties and becomes a thermosetting material after polymer cross-linking. In the past two decades, it has become the dominant variety of medium and high voltage power cables in China, which can be applied to6——330Among various voltage levels of kilovolts.

In recent years,1The cross-linking of kilovolt low-voltage cables has become a technological direction, and the key is to reduce the insulation thickness so that it can compete with polyvinyl chloride cables in terms of price.

3Insulated power cables impregnated with viscous oil1992Years ago, it was the leading product of medium voltage cables in China. This is the classic structure of power cables, which has a history of over a hundred years. It has a large margin of electrical and thermal performance and a long service life (still in use in China)1923Imported cables laid annually. However, due to multiple production processes, long cycles, and limited material sources, it has been replaced by cross-linked polyethylene cables.