This wire is inside a tube, wrapped in a tube, and surrounded by insulating gas, called a "gas insulated circuit".

What is gas insulated circuit?

It is a power line that encapsulates conductors in compressed insulating gas pipelines, known as gasinsulated line or GIL in English.

As its name suggests, it is a high-voltage, high current, long-distance electrical energy transmission equipment that uses sulfur hexafluoride or a mixture with other gases to achieve insulation, with the shell and conductor arranged coaxially. This type of transmission line has the advantages of large transmission capacity, less land occupation, high reliability, no/less maintenance, long service life, and low environmental impact. With the advancement of technology, in high-voltage and special application scenarios, the cost of transmission lines is no less than that of cables, and the transmission capacity and reliability are significantly higher than those of cables.

China's 1100 kV gas insulated transmission line,

The live assessment test section of the ultra-high voltage (1100 kV) gas insulated transmission line, undertaken by the State Grid Electric Power Research Institute, has successfully passed live operation tests such as power frequency withstand voltage, partial discharge, air tightness, and circuit resistance at the Wuhan ultra-high voltage base.

State Grid Electric Power Research Institute has conducted practical research on environmentally friendly gas insulated lines, using nitrogen/sulfur hexafluoride mixed gas as the insulation medium. In the previous application of environmentally friendly mixed gas to ultra-high voltage gas insulated lines, it broke the technological monopoly of foreign countries in this field.

The * sets of million volt mixed gas insulated lines independently developed by our country have passed the full set of type tests, and have also made comprehensive breakthroughs in the research and development of 550 kV and 220 kV mixed gas insulated and sulfur hexafluoride gas insulated line products. The line products have successfully passed the full set of type tests.

What is the use of tall wires?

With the construction and development of the energy internet and China's strong smart grid, there is a huge potential market demand for gas insulation products for special applications and industrial applications, especially for areas where it is difficult to build overhead lines across rivers, power plants or hydropower stations, as well as urban centers with tight transmission corridors and concealed transmission lines.

The successful development of a million volt mixed gas insulated transmission line provides strong technical support and engineering reference for the design, installation, testing, and long-term reliable operation of the equipment structure of the GIL pipe gallery project in the early stage of the "Sutong River Crossing" of the Huainan Nanjing Shanghai 1100 kV high-voltage AC transmission project.