Based on comprehensive media reports and recommendations from netizens, the SASAC News Center carefully selected 20 super-engineering projects—each combining high media attention with substantial technical and operational significance—from among the key construction projects of central enterprises in 2025. The center then launched an online voting campaign, which drew participation from more than 850,000 netizens. Based on netizens’ likes and expert opinions, the “Top Ten Super Projects of Central State-Owned Enterprises for 2025” have been announced.

Longdong–Shandong ±800 kV UHVDC Project

The transmission lines of the Longdong–Shandong ±800 kV UHVDC project

On May 8, 2025, the Longdong–Shandong ±800 kV UHVDC project was completed and put into operation. This project is a major energy artery under China’s “West-to-East Power Transmission” strategy. It originates at the Qingyang Converter Station in Qingyang City, Gansu Province, and terminates at the Dongping Converter Station in Tai’an City, Shandong Province. It employs ±800 kV rated voltage and 8 million kilowatt rated capacity ultra-high voltage direct current (UHV DC) technology—referred to as “Double 800” for short—over a transmission distance of 915 kilometers. With a total investment of RMB 20.2 billion, it is China’s first outbound transmission project from a large-scale integrated energy base that combines wind, solar, thermal, and energy storage resources; the first UHV DC project to achieve full-capacity commissioning in a single phase; the first demonstration project to explore and apply standardized outcomes of the “Double 800” UHV DC technology; and the first demonstration project to break through critical UHV bottlenecks by leveraging the results of a national key research initiative.

The Longdong–Shandong ±800 kV UHVDC project can annually transmit more than 36 billion kWh of electricity continuously from Gansu to Shandong’s load centers, substantially strengthening Shandong’s energy and power supply security and providing robust impetus for the province’s economic development. The project also strongly supports the development of large-scale “sand, gobi, and荒” base projects and the large-scale utilization of new energy resources, ensuring reliable transmission of over 10 million kW of new energy generation capacity. It facilitates the conversion of Gansu’s resource advantages into economic benefits through wider-area optimal allocation, thereby accelerating the establishment of a nationally significant new energy base.

Relying on a series of national major science and technology projects, the project successfully developed and deployed a UHV converter transformer tap changer with fully independent intellectual property rights, as well as a DC control and protection system based on domestically developed, controllable chips. This represents a new breakthrough in China’s self-reliance and controllability of electrical equipment, significantly enhancing the resilience and governance capabilities of the country’s high-end power transmission and transformation equipment industry chain and supply chain.