Harbin Electric Celebrates Milestone with Fabrication of the World's Largest Impulse Runner

HARBIN, China, Jan. 3, 2025 /PRNewswire/ -- On December 30, Harbin Electric Corporation ("Harbin Electric"), a global leader in power generation technology, achieved a significant milestone in hydropower technology with the successful welding and manufacturing of the world's largest single-capacity and largest-sized impulse turbine runner. The engineering feat led to the launch of the globe's first 500 MW single-capacity impulse hydroelectric generator set at the Zhala Hydropower Station. The achievement marks a major breakthrough in China's research and development of high-head, large-capacity impulse hydropower units, positioning the country at the forefront of global innovation in this field.

The hydraulic turbine runner functions as the "heart" of the hydroelectric generator unit at the Zhala Hydropower Station, a critical component of Electricity Transmission of China's Xizang project. It supplies the essential power for the unit to achieve a rated output of 500 megawatts. Under the direction of the project's owner China Datang Corporation, Harbin Electric Machinery Company ("Machinery Company") has independently developed the state-of-the-art impulse runner, boasting energy conversion efficiency that meets world-class standards. The runner is constructed with a forge-welded structure that includes one hub forging and 21 bucket forgings, resulting in a post-welding weight of 90.8 tons.

An impulse turbine is a type of hydraulic equipment that utilizes a pressure pipe to channel water flow onto an impulse runner for energy conversion. At the Zhala Hydropower Station, with a design head of 671 meters indicating a significant vertical drop and high pressure, the runner functions as a crucial load-bearing and flow-through component that directly impacts the efficiency of the hydropower unit. Throughout its operation, the runner withstands high-frequency dynamic pressures, which are critical to the unit's stability and safety. Consequently, the welding and manufacturing requirements for the component are particularly stringent.

As the world's largest single-capacity impulse turbine runner, this component's hub forging boasts a diameter of 4.7 meters and a thickness of 1 meter, setting a world record for the largest martensitic stainless steel forging. The runner has a maximum outer diameter of 6.23 meters and a width of 1.34 meters, making it the largest impulse runner in the world. The manufacturing technologies for welding and processing, given the material, shape, and size, are at the forefront of their respective fields. Exploring these techniques involves numerous risk factors and uncertainties, presenting exceptionally high requirements and significant challenges in both welding and manufacturing.

To overcome the welding challenges associated with the manufacturing of the runner, the Machinery Company launched a technical initiative, employing digital simulation technology to investigate die forging techniques for large buckets. The company chose the highly efficient forging and welding manufacturing process due to its exceptional performance. Through 3D metrology and simulation calculations, the assembly and welding process was optimized by identifying the most effective welding parameters. The hub and buckets, crafted from martensitic stainless steel forgings, were joined using high-strength, resilient welds, significantly enhancing the runner's impact toughness and fatigue resistance.

The Machinery Company formed a specialized runner welding technology team for the Zhala Hydropower Station to address the tough welding requirements of martensitic stainless steel and the intricate, curved structure of the ultra-thick bucket runner. The team performed detailed analysis and research on key welding manufacturing technologies, focusing on welding materials and processes, bucket positioning, welding station setup, welding distortion management and weld quality assurance. Through the process, the team developed a comprehensive suite of welding technology solutions, providing essential technical support for the efficient and high-quality fabrication of the 500 MW impulse runner.

By establishing the Zhala runner welding fabrication team, the Machinery Company deployed highly skilled and experienced welders and craftsmen to handle the welding tasks. At the same time, the company implemented lean management initiatives to ensure quality, maintain progress, and enhance efficiency. The cold work sub-factory, tasked with welding operations, played a crucial role in integrating production with technology. To enhance quality and efficiency, the sub-factory conducted extensive research and discussions on technological approaches and carried out multiple simulations, ensuring the seamless progression of the production process.

Despite the confined operating spaces between the buckets, members of the welding fabrication team effectively addressed several challenges, including high temperatures, the complexities of backhand welding, and the demanding task of cleaning between layers. They employed tungsten inert gas (TIG) welding for deep joints and metal active gas (MAG) welding for other positions, ensuring comprehensive, multi-layer quality control throughout the runner welding manufacturing process. After 107 days and a total of 1,712 hours of dedicated effort, the Machinery Company successfully navigated the challenges of welding the runner for the Zhala Hydropower Station, achieving a manufacturing milestone with the successful creation of the world's first 500 MW impulse turbine runner.

Through the welding fabrication of the 500 MW runner, the Machinery Company effectively addressed the complex challenge of welding large, thick, low-carbon martensitic stainless steel forgings. The company successfully overcame the challenges of welding complex, curved, ultra-thick buckets, and mastered the critical technologies for manufacturing processes that reinforce surfaces with ultra-high bonding strength. The achievement marks a significant breakthrough in China's manufacturing technology for electric power equipment. It also represents a key milestone for the Machinery Company in its quest to advance technological innovation, aligning with China's strategy to accelerate the construction of hydropower facilities in Southwest China. In addition, this accomplishment sets a new benchmark in the sustainable development of the country's energy equipment manufacturing industry.

The Zhala Hydropower Station, located in Zogong County, Chamdo within the Xizang Autonomous Region, serves as the focal point of the Southeast Xizang Clean Energy Integration Hub and is acknowledged as the world's most challenging impulse hydropower project currently under construction. It features two 500 MW impulse hydropower units, which are the largest of their kind in terms of single capacity, power output, and technological sophistication. Recognized by the China National Energy Administration as a pioneering project in the country's energy sector, the Zhala Hydropower Station distinguishes itself as China's exclusive demonstration project for the development and application of the 500 MW high-head, large-capacity impulse hydropower unit.

The Machinery Company is a leader in China in the research and development of impulse hydropower units. Through decades of technological innovation, the company has perfected a unique design and manufacturing process for these units. Harbin Electric has developed and produced 67 impulse hydropower units for 30 power stations worldwide, including the Dongchuan Hydropower Project in China, the Minas plant in Ecuador, the San Gabá facility in Peru, and the Suki Kinari project in Pakistan. Through its involvement in these projects, the firm has gained expertise in advanced technologies for impulse hydropower units while accumulating extensive practical engineering experience in hydraulic development, model testing, structural design, as well as in the processing, manufacturing, transportation, installation and commissioning of key components.