Detail the highlights of the UHVDC transmission project in northwest Yunnan

Recently, China Energy Construction has designed 8 units of the General Institute of Electric Planning, Northeast Institute, Central South Institute, Southwest Institute, North China Institute, Jiangsu Institute, Hunan Institute and Guangdong Institute, and Guangdong Thermal Power participated in the construction of the world altitude, fortification and seismic level UHVDC transmission project - 800 kV UHVDC transmission project from northwest Yunnan to Guangdong ± has been fully put into operation.

The project starts from Xinsong converter station in Jianchuan County in the west to Dongfang converter station in Bao'an District, Shenzhen in the east, with a total length of 1,956 kilometers, a transmission capacity of 5 million kilowatts, and a planned annual transmission of 20 billion kilowatt-hours, equivalent to 1/4 of Shenzhen's annual electricity consumption.

In the process of project construction, all units of China Energy Construction concentrated superior resources to carry out scientific and technological research, and technological innovation highlights appeared frequently and achieved fruitful results.

For the first time in UHVDC lines, the vertical arrangement of DC lines and grounding lines in the same tower erection technology is adopted, which compresses the corridor width by about 40 meters, reduces the demolition and relocation by about 60,000 square meters, reduces the occupation of land resources and the amount of demolition, and reduces the difficulty of the agreement.

For the first time, the "swallow-wing" cross load was adopted in the UHVDC line, and the conductor spacing was shortened from 28 meters to 22 meters after optimization, while the tower weight was basically not increased, creating good economic and social benefits.

Using Hailawa technology and high-definition satellite images, aerial films, geological remote sensing and GPS, the optimal selection of the large path scheme and the local scheme were compared in detail, and the path scheme was selected to reduce the project cost.

Adopt negative protection angle design to reduce the tripping rate of lightning strikes. According to the calculation results, the whole line tower adopts a negative protection angle design to achieve the goal of making the expected lightning trip rate of UHV line lower than 500 kV line.

Determine economically sound tower plans. Using the technology of aerial film, DEM digital ground model and transmission line optimization decision-making software, and using the principle of dynamic planning, the pole tower planning and research was carried out in the wind division area and ice area, which effectively and reasonably controlled the project cost while ensuring the safety of the line.

The long and short legs of the tower are used in conjunction with the high and low foundations. The area through which the line passes, the terrain is complex, there are many mountains and hills, and the combination of the long and short legs of the iron tower and the high and low foundations effectively solves the problem of too large the base surface and achieves the environmental protection purpose of less or no square opening.

Segmented differentiated configuration for improved insulation levels. The whole line is equipped with differentiated insulation according to the number of insulators and arc angle gap values, which effectively solves the insulation flashover problem of grounding lines by improving the insulation level of grounding lines, and ensures the safe and stable operation of grounding lines and even DC transmission systems.

Prepare special plans to overcome difficult construction technology difficulties. The single-base tower weighs 306 tons and the tower is 130 meters high; The length of the cross is about 45 meters, and the weight of the single-section cross lift reaches 7.6 tons, which is relatively high in the same type of UHV construction in China, and the construction technology requirements are high. The project department organized experts to conduct repeated demonstrations, prepare special construction plans, and carry out construction in strict accordance with the plan.

China Energy Construction strictly abides by the principle of scientific rigor, strengthens process management, grasps all links such as prior guidance, intermediate inspection, and finished product review, carries out refined management, and puts the project into operation on time.