On April 21, 2026, China Energy Engineering Southwest Institute participated in the survey and design of the Chongqing Guizhou Back to Back Interconnection Project, and the Chongqing side 500 kV supporting project officially broke ground. The total investment of this project is about 537.9 million yuan. As a key node of the national southwest energy corridor, the project aims to solve the problem of power supply and demand mismatch between Chongqing and Guizhou, and enhance the regional power grid's ability to resist risks. The project involves the construction of 58 kilometers of 500 kV double circuit transmission lines and 1.5 kilometers of single circuit transmission lines on the same tower, totaling 59.5 kilometers of transmission arteries. 138 towers will be erected, and 113 kilometers of optical cables will be replaced and 5 kilometers of transmission lines will be relocated. It is planned to have live conditions by April 2027.

Cracking the Difficulties of Mountain Construction

The project passes through 9 townships including Longsheng Town in Qijiang District, Chongqing. The terrain along the route is mainly mountainous and hilly, with an altitude difference of over 800 meters, and the construction site is extremely limited. The design team of China Energy Engineering Southwest Institute adopts 3D laser scanning and digital twin technology to model the micro terrain along the line at the millimeter level, optimize the site selection of 12 tower locations, reduce the excavation volume of earth and stone by about 150000 cubic meters, and improve the soil and water conservation coefficient to 0.95.

For the double loop large-span section of the same tower, Q420 high-strength steel is used in the design, and the weight of the single base tower is controlled within 110 tons, which is 15% lighter than the traditional design. At the same time, unmanned aerial vehicle tensioning and laying technology is used to improve the efficiency of the overhead line by 40%. Keywords: power engineering, ultra-high voltage

After the project is put into operation, it will form a mutual aid capacity of 3 million kilowatts with the existing Chongqing Guizhou corridor. It is expected to transport over 15 billion kilowatt hours of clean electricity annually, which is equivalent to reducing standard coal consumption by 4.5 million tons. As an important puzzle for energy security in the Chengdu Chongqing economic circle, this project will effectively alleviate the summer peak load pressure in Chongqing and provide strong grid support for the consumption of new energy in the southwest region.Editor/Cheng Liting