Recently, an "electricity superhighway" was completed and put into operation, stretching between the Loess Plateau of Longdong and the fertile plains of Qilu. The Longdong-Shandong ±800 kV Ultra-High Voltage (UHV) Direct Current (DC) Transmission Project starts at the Longdong Converter Station in Qingyang, Gansu, and ends at the Dongping Converter Station in Tai'an, Shandong, spanning 915 kilometers. It is China's first large-scale integrated energy base transmission project combining wind, solar, coal, and energy storage. SDEPCI, serving as the overall line design coordinator and the designer of the receiving-end converter station, was responsible for the survey and design of the DC line section in Shandong, the receiving-end electrode line, and Package B of the Dongping Converter Station.
Coordinating Multiple Forces to Chart the Blueprint
As the overall line design coordinator and receiving-end converter station designer, SDEPCI took on the crucial task of coordinating nine design institutes. Facing complex terrains ranging from the Loess Plateau in Gansu to the Yellow River Gorge and Shandong’s hilly regions, the team adopted the State Grid’s innovative model of "joint design + unified management." Collaborating with various design units, they conducted specialized studies on lightning protection and conductor selection, inviting experts from construction and equipment manufacturing fields to jointly make decisions, achieving a perfect balance between technical standardization and regional adaptability.
Liu Xiaolin, the chief line designer of the project from the Power Grid Institute, recalled, "This was a three-year hard-fought battle." From the feasibility study in 2022 to the construction drawing design in 2024, the team consistently adhered to the principle of "integrated survey and design." At the Yellow River crossing section in Liaocheng, they achieved a breakthrough by designing DC lines and electrode lines on the same tower for the first time. Considering the shorter span and lower height of the electrode line, they redesigned the tower structure and insulation configuration, providing a "Shandong solution" to the challenge of limited corridor resources in national mega-projects.
Innovation Empowers Mega-Project Construction
The Dongping Converter Station is the first demonstration project in China to apply the "Dual 800" standardization achievements. The entire station's design was categorized into eight modules, 11 types of building layouts, and 20 standardized equipment configurations, resembling "power building blocks" to enhance construction efficiency.
A notable breakthrough was the successful application of the 500 kV fast AC circuit breaker. This next-generation breaker, an improvement over conventional models, was developed to reliably and swiftly clear internal faults in UHV converter transformers, preventing fire and explosion risks. It reduces the breaker’s opening time from the conventional 50 milliseconds to just 25 milliseconds, effectively "armoring" the converter transformer against explosions. This "first-in-China" breakthrough establishes a new safety benchmark for UHV equipment operation.
Sun Zhongwei, the chief substation designer of the project, noted, "Behind every blueprint lies the meticulous effort and dedication of the design team." From early trial-and-error exploration to today’s standardized design, the team tackled dozens of technical challenges. From millimeter-level precision in conductor arrangement to intelligent enhancements in converter station equipment installation, their series of "zero-to-one" breakthroughs have turned the project into a "standardized textbook" for UHV engineering, offering replicable and referential "Shandong experience."
Energy Interconnection Writes a New Chapter
When wind, solar, and coal power from Longdong, regulated by energy storage systems, transform into stable current and travel 915 kilometers to the Dongping Converter Station, the grand vision of "wind-solar-coal-storage integration" becomes more than just a technological breakthrough—it is a vivid practice of China’s "3060" carbon goals. For Gansu, this is a golden channel for clean energy to "go out"; for Shandong, it is a green engine for energy structure transformation.
In terms of construction significance, the project set four national "firsts":
1. China’s first UHV DC project integrating wind, solar, coal, and storage for power transmission.
2. The first UHV DC project in China to achieve full-capacity operation in a single phase.
3. The first demonstration project to explore and apply the "Dual 800" UHV DC standardization achievements.
4. The first demonstration project to apply China’s "1025 Special Project" breakthroughs in resolving UHV bottleneck technologies.
"What we built is not just a physical power line but a bridge for energy synergy between eastern and western China."
Standing beneath the steel structures of the Dongping Converter Station, surrounded by towering equipment and crisscrossing power lines, the builders know that their blueprints have transcended the project itself. This "four-first" super project, leveraging Shandong’s expertise as a fulcrum, is propelling China’s UHV technology to another historic leap. The warm sunlight of Longdong illuminates the transmission towers, while the glittering lights of Shandong’s households mirror the starry sky. This magnificent energy corridor has become the most vivid footnote of the new era’s "West-to-East Power Transmission."
