Power cables and accessories are the key products used for transmission and distribution of electric energy in the main line and distribution network line of power system, mainly including AC power cables and accessories with rated voltage U0 / u 0.6/1kv ~ 290 / kV. Among them, the rated voltage of 1.8/3kv and below is low-voltage power cable, 3.6/6kv ~ 26 / 35kV is medium voltage power cable, 66kV ~ 110kV is high-voltage power cable, and 220kV and above is ultra-high voltage AAC Cable. In recent years, China has promoted the development and application of flexible DC cables, including DC power cables and accessories of various voltage levels within the rated voltage uo10kv ~ 525kv.
Power cables are basically distinguished according to the types of insulating materials. Extruded solid insulated power cables represented by XLPE insulation materials have been widely used. At the same time, there are a small number of oil immersed paper insulated (hereinafter referred to as “Mi cable”) power cables and oil filled (hereinafter referred to as “of cable”) insulated power cables“ During the 13th Five Year Plan period, superconducting power cables and Gil gas insulated lines have also been continuously developed and applied in engineering. PP (polypropylene) thermoplastic insulation material with environmental protection characteristics is known as a new type of ACAR Cable, which is being developed and applied in engineering demonstration in China.
Power cables are divided into land cables and submarine cables according to use scenarios. In recent years, submarine cables have been rapidly developed and widely used, especially the development of offshore renewable energy (wind power generation), which promotes a large demand for submarine cables.
6kV and above power cables need to be equipped with cable accessories of corresponding voltage level. Cable accessories include terminals and intermediate joints, including wrapping, molding, cold shrinkage, heat shrinkage, prefabrication, combination and other forms.
Power cables, whether land cables or submarine cables, whether AC cables or DC cables, are characterized by a wide range of voltage levels, from 1kV to 500kV. At present, the voltage level tends to be higher; Wide specification range, from 1.5 mm ² To 3500 mm ²， At present, the conductor section tends to be larger. Power cable is not only widely used in distribution network, but also an important foundation and indispensable product of power transmission in backbone network (Note: concentrated in urban power supply system). With increasing transmission capacity, operation safety and reliability are becoming more and more important. People not only pay attention to the quality improvement and technical improvement of power cables and accessories, but also study the operation reliability of AAAC Cable system, including electrical factors, mechanical factors, temperature and environmental factors, as well as mutual integration and coordination; It also pays more attention to the economy and long-term operation of power cable system, including transmission capacity, loss, maintenance cost and rapid recovery ability in emergency. Therefore, the power cable system is facing the challenges of quality improvement, operation economy, reliability and durability, involving material innovation, structure innovation and manufacturing process innovation. Facing the new requirements of social progress, urban development and environmental coordination, the challenge of long-distance transmission underground cable with large capacity, low loss, convenient laying, operation and maintenance and intelligent control, as well as the development and application of marine resources and new energy, and the challenge of safe power transmission reliability in complex environments such as seabed.
In recent years, China’s cable industry has made great progress in the above fields, but there is also a lot of room for improvement, improvement and promotion. In the manufacturing field, the integration of fine management, informatization, equipment automation and digitization of power cable manufacturing to realize high-quality intelligent manufacturing and development is still on the road. In the application field, there is still a big gap between the construction of high-voltage, large capacity and long-distance underground and submarine transmission networks and the development and application of corresponding materials and high-end equipment and the technical level of advanced countries.