Since 1986, the research on UHV transmission technology has been included in the national "Seventh Five-Year Plan", "Eighth Five-Year Plan" and "Tenth Five-Year Plan". In the past two decades, Chinese research institutions have done a lot of work in the field of UHV, and UHV technology research has entered into practical technology research and experiments, and a number of important scientific and technological achievements have been achieved. China Electric Power Research Institute, Wuhan high voltage Research Institute, electric power construction research institute and related institutions of higher learning have carried out the study on the selection of uHV long distance power transmission mode and voltage level, and carried out the analysis and demonstration of uHV power transmission equipment, lines, towers and typical substation, and the study on the impact of overvoltage, insulation coordination and transmission lines of uHV power transmission system on the environment.
The tower and pole test station built by Electric Power Construction Research Institute in 2004 carried out the prototype strength test of UHV single loop 8×800 split conductor, 30 ° ~60 ° Angle tower and UHV transmission line anti-vibration design scheme.
In order to carry out the technical research on uHV transmission as soon as possible in our country, and promote the development of uHV transmission in our country, at the beginning of 1994, the "National Leading Group for Networks and High voltage transmission" of the former National Ministry of Electric Power passed the expert certification, and decided to build the uhV test research line segment in the outdoor high voltage test field of the Wuhan High Voltage Research Institute. In June 1996, a million volt ultra high voltage test research line was built. The test line segment can be used to carry out the research on the external insulation discharge characteristics of UHV transmission technology and the line's impact on the environment. It can also be used to carry out the examination test on some electrical products and components. Its completion provides favorable conditions for the research of higher transmission technology.

The main characteristics of the experimental research line segment are as follows:
1) Meet the research of UHV transmission related technologies
The line segment has the characteristics of large voltage range for application research, flexible and convenient adjustment, and can meet the test research of external insulation and environmental impact projects with voltage range of 800 ~ 1200kV.
2) Use true type to simulate pull V-shaped tower
Because the tower covers an area of small, the application is wide and the tower is easy to change the tower type with the simulation plate, the simulation tower in the test line segment chooses the real type simulation tower. The tower can be used to simulate the actual line tower to test and study the insulation characteristics of the line tower and the discharge characteristics of the insulator string.
3) The gap size of tower window can be changed
In the design of the real type simulated pull V tower, the size of the tower has a margin, and the side of the tower is provided with a plurality of lifting points on the cross arm, so that the gap size can be changed during the test.
4) The length and type of insulator can be changed
String length of insulators (glass insulators, porcelain insulators and synthetic insulators) can be changed by certain construction methods (such as increasing and decreasing the number of pieces of insulators).
5) Different types of wires that can be suspended
It can hang 8 or 10 split LGJ400, LGJ 500 or LGJ 630 wires to study the corona characteristics of different wires and the insulation characteristics of the gap.
By using this experimental research line segment, the actual operation of lines and towers can be simulated on the spot, and the following practical technologies of UHV transmission can be researched:

1) Study on insulation discharge characteristics
The discharge characteristics of the gap (such as tower window gap, wire-tower gap, arc starting Angle gap, etc.), the volt-second characteristics of the impact discharge and the discharge characteristics of the insulator string are studied.
2) Line and tower research
Research on corona characteristics of line, insulator voltage distribution, large section traverse, line fittings and live line operation technology is carried out.
3) Research on the environmental impact of the line
The environmental impact (radio interference, electrostatic induction, audible noise and ecological impact, etc.) of the line has been studied.
4) long-term power frequency pressure test
Line segment has the ability to apply single-phase power frequency high voltage for a long time, and can carry out long-term power frequency pressure test on UHV small capacitance electrical products or components, so as to constantly improve and perfect the design of product and component structure.