The wire and cable industry is one of the most important sectors in the electricity transmission and distribution network. Due to the high cost of wires and cables, this segment is one of the most expensive parts in both project execution and equipment maintenance.
Investigating and solving the challenges of this sector can save a lot of money on costs. Nanotechnology as a new approach can address some of the challenges in the wire and cable industry. This technology can be applied to the coatings and coatings used for cables and can extend the life span as well as corrosion and caries resistance. Nanotechnology can increase the transient power by increasing the insulation strength of the cladding and the wiring, which will also save a great deal of economic savings. Other applications of the technology, which is mostly in the research phase, include increased efficiency and reduced cable loss. Immunization, given the high economic returns, can also be a good investment topic.
As power consumption continues to increase, transmission lines are constantly expanding, as major and major energy exchanges across national networks are carried out by high-capacity power lines. Undoubtedly, conductors are the most important components of any power transmission network and the flow path through them. All arrangements are made in the design of a high pressure line only for the proper and safe transmission of electrical energy through conductors.
Cable is basically any conductor that can transmit electricity and be insulated by its surroundings, so that the insulation surface voltage is equal to zero and the conductor itself has a fuzzy voltage
The cables consist of three main parts: conductor, insulation and external protection (external protection may consist of several parts). The main part of the cable, which is the conductor, is responsible for directing the current. After the wire, an insulating layer is wrapped around the cable conductor, which separates the cable conductors from each other and the surrounding environment. Many cables, such as low-pressure cables, telecommunications, and so on, have only two components, but with the increase of voltage, cable construction becomes more complex. External protection protects cable from mechanical, chemical and other damage.
The main part of the cable is the conductor of the current. The conductors are usually copper and aluminum. However, at present almost all cables used are copper conductors, due to their greater conductivity, better resistance to moisture and atmospheric factors, greater mechanical strength and better copper ductility than aluminum. The cable conductor may be in strings, wires, circular or triangular.
Electrostatic coatings are used to prevent partial discharge between the possible distance between the insulator and the conductor. A semiconductor cover that is twisted on wires to prevent partial discharge between the conductor and the insulator by unifying the conductor surface and the field.
Oil-impregnated paper is one of the most common insulators used in older cables.
The insulation endurance of the paper used in the cables is K7/cm70 which increases to K7/cm600 after oil impregnation.
But the oil used in cables and other equipment can contaminate the environment and in some cases lead to fire, so the use of other insulators has been considered. Today, almost all cabling plants use synthetic insulators. Synthetic insulators used in the cables include polyvinyl chloride (PVC), thermoplastic polyethylene (PE), rubber or similar ethylene propylene (EPR) and crosslinked polypropylene (XPE) compounds. Due to the different specifications of these materials, each can be used to make cables with different operating environments in terms of maximum temperature, insulation tolerance, etc.
Exterior protection sheath
Thermoplastic sheets such as PVC, XLPE, or aluminum and lead sheets are used to protect the cables from moisture and corrosion. PVC sheaths can withstand high temperatures and even flame and are resistant to all soil chemical constituents.
Lead sheath is mostly used in paper-insulated cables, and the main task of the metal sheath is to protect the paper against moisture.
Aluminum sheets are used because of their lightness and moisture resistance. Also, due to the high conductivity of aluminum, the sheath is sometimes used as a conductor.
The armor protects the cable against mechanical forces. Lead-insulated paper insulated cables are usually armored by steel strips. No armor is required if the XLPE insulated cables with copper lattice and PVC and XLPE insulated low pressure cables are not exposed to tensile stresses. Cables that are subject to higher mechanical stresses should be armored with galvanized steel wires.
Challenges in cables
Challenges in cables can be attributed to the high weight of conductors that can cause damage to equipment and structures.
Another major challenge is the loss of electrical energy. 1.5% of total power generation in the transmission to distribution sectors in the Iranian electricity industry is wasted, with most of the losses being in the wires and cables sector. Another challenge in cables is the insulation used which results in thermal energy caused by continuous load current, connection current, etc., which can cause damage to the connection and fire.
Nanotechnology in Cables:
Carbon nanotube fibers are one of the major achievements of nanotechnology. These nanotubes have found significant applications in the cable and wire industry. Carbon nanotube (CNT) fibers with high electrical conductivity and far better than copper have a significant impact in reducing losses. Assuming 1% nanotube-to-nanotube conductivity efficiency over fibers and compression density of 2 CNTs per square centimeter, it transmits a stream of carbon nanotubes with a flow rate of 5 million amps that equals 5 times the best superconducting transfer capacity. The heat is low. With current technology, transmission line losses are about 5 percent, reducing those losses by 5 percent to an annual energy saving of 2 kWh and an estimated 1 million bushels. This reduction in losses also results in significant savings in coal and gas consumption and a reduction in carbon emissions in the electricity industry. The development of this material in the world markets is also noticeable. For example, global demand for carbon fiber is expected to grow from 4,000 tonnes a year to more than 6,000 tonnes a year.
In addition to electrical conductivity in carbon nanotubes, they have very good mechanical strength (to the strongest type of steels), which also results in good mechanical properties of this material.
Nanocomposites based on polymeric materials and clay nanoparticles can also be used to improve the insulating properties of the electrical casing. In addition to its good mechanical properties, these materials have other properties such as high fire resistance for wire insulation.
There is no commercial activity in the country, but given the capacity available, suitable conditions can be developed and implemented for this area.