PFA is an excellent organic high temperature resistant material, with mechanical properties, chemical resistance, weather resistance, electrical properties, low dielectric constant, low flammability, low moisture absorption, anti-fouling and other excellent mechanical and chemical properties. PFA has been favored by the cable industry for its excellent and safe electromechanical performance. Wire and cable industry commonly used in the PFA are: polyethylene propylene fluoride (FEP, F46), polychlorotrifluoroethylene (PCTFE), polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene copolymer (ETFE, F40), polyvinylidene fluoride (PVDF), etc., the above materials have been safe for cable insulation sheath for many years. The main types of PFA insulated cables are: high temperature resistant compensation wires, high temperature resistant signal wires, Ethernet wires, industrial high temperature resistant power and control cables, rail transit locomotives with high temperature resistant power and control cables, high temperature heating cables, etc. PFA insulated frequency conversion power cable is mainly used in steel, metallurgy, petrochemical, power stations and other places with harsh high temperature operating environment of frequency conversion equipment power transmission connection line, the general temperature range of -65 --- 260 ℃. With the rapid development of China's economy, the demand for high-temperature cables in special industries is becoming more and more exuberant. According to incomplete statistics, heat-resistant and high-temperature cables are growing at a rate of more than 15% every year. However, although PFA has thousands of benefits, it has not issued its national standards. At present, only industry standards issued by research institutions are applied in China. The following will focus on the national standards and industry standards of PFA insulated cables at home and abroad.

With the rapid development of China's economy brought about by the reform and opening up, more and more enterprises have PFA cable production capacity. Due to the unique attribute of heavy materials and light industry in the cable industry, many cable factories in China have successively introduced production lines such as physical foaming and irradiation crosslinking. At present, PFA cables such as computers, buildings and industries are basically self-sufficient and do not need to be imported, most enterprises can produce 0.6/1kV and below PFA fireproof cable, PFA high temperature silver plated cable and control cable, PFA can only be used for 1kV and below voltage level of cable.

Although the wire and cable industry is a traditional industry, but China currently no national standards for PFA insulated cables, only cable or machinery and other related industry research institutions and authoritative scientific research units have some standards, they are: two technical specifications of "rated voltage 0.6/1kVPFA insulated PFA sheathed power cable" and "rated voltage 0.6/1kV and below PFA insulated PFA sheathed control cable" compiled by the national wire and cable quality supervision and inspection center; GJB773A-2000 "Fluoropolymer Insulated Wires and Cables for Aerospace", HG/T2904-1997 "Polyfluoroethylene Propylene Resin for Molding and Extrusion" (equivalent to ASTMD2116-02 "Fluorinated Ethylene Propylene (FEP)-Fluorocarbon Molding and Extrusion Material"), EN50306:2002 "Railway Application-Railway Vehicle Cables with Special Fire Resistance-Thin Wall" and other standards. The basic model of PFA insulated cable in China is shown in Table 1.

The foreign cable industry started earlier. Take the French cable giant Nexans Cable Group as an example. The company has been developing high-temperature PFA insulated wires and cables for aerospace since the 1830 s. After nearly a century of development, the company has become It is the largest cable manufacturer in the aerospace industry, and its products have basically covered all fields of aerospace cables. Today, many foreign cable companies with excellent PFA insulation materials, mature process control, firmly occupy the market of this high-end cable.

Take the polyethylene glycol propylene insulated power cable as an example, the price of polyethylene glycol propylene is more expensive, in the insulation or sheath process production requirements are thinner, the production quality of the conductor will directly affect the appearance and performance of the finished cable.

In the process of conductor stranding, it is necessary to ensure that the diameter of monofilament in the conductor is consistent. When the conductor is stranded on the coil, it is necessary to ensure that the flat wire is neat and uniform in tension. If the conductor tension is uneven or the flat wire is disordered, the monofilament in the conductor will jump or scratch the insulation during insulation extrusion, thus affecting the next process. At the same time, due to the thin insulation of PFA, when the conductor is stranded, it is necessary to carefully check whether there are burrs, protrusions, oxidation and other abnormal phenomena on the surface of the conductor.

High-temperature PFA insulated cables cannot be water-cooled with ordinary PVC insulated cables, because ordinary water cooling will crack the PFA insulation surface. Therefore, a constant temperature cooling device is installed in the water cooling tank to control the water temperature. During the cooling process, the internal stress on the inner and outer surfaces of PFA insulation (caused by uneven heat dissipation) is effectively improved. At the same time, due to the high cost of PFA and the thin insulation thickness, it is extremely necessary to train employees before production.

At present, only a few PFA insulated cables can be produced by physical foaming in our country, and the quality of the products is uneven. Among them, there are reasons for equipment and research and development of PFA materials for cables. However, one reason that cannot be ignored is that there is no unified national standard for PFA cables currently widely used in our country,PFA GranulesEnterprises are independent. Even if the National Wire and Cable Supervision and Inspection Center has issued corresponding technical specifications, the structural dimensions, materials, voltage levels, temperature application scope, and places of use of PFA cables produced by most enterprises are not uniform. These problems make the domestic PFA cable market present a bad situation of "a hundred flowers blooming", which brings confusion and potential safety hazards to users' selection, use and maintenance. If the relevant functional departments of the state take the existing PFA cable standards (TICW2, TICW3, etc.) as the benchmark and combine the international standards such as UL, VDE, EN and the actual situation of domestic PFA cables to formulate a unified national standard, it is believed that the current situation of domestic PFA cable products with mixed quality and "Zhang San Li Si" will be effectively improved.

It is worth noting that the PFA cable has a self-extinguishing function. It is understood that an Italian cable co., ltd., one of the world's cable giants, has disclosed a power cable with self-healing function. a fluid is filled between the cable insulation and the sheath. when the sheath is broken, the fluid between the damaged insulation and the sheath will quickly fill the damaged sheath, quickly heal the damaged sheath, and achieve the self-healing function.

The number of PFA particle enterprises in China is the largest in the world, and the products basically cover all kinds of wires and cables. However, the products of most PFA enterprises in China are concentrated in the fields of medium and low voltage power cables, distribution wires, power cords and other common products. In recent years, enterprises, scientific research institutions, administrative agencies and other departments in the wire and cable industry actively advocate the development of high-end products, china's PFA insulated cables should fully develop more superior insulation materials, formulate national standards, unify operating specifications, and promote the efficient improvement of product quality in the industry.

This article comes from:www.tflpfa.com

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