On March 19, Dongfang Electric Corporation's Dongfang Motor Co., Ltd. announced that the third runner of its domestically developed upgrade and retrofit project for the Dachaoshan hydropower units in Yunnan Province has been successfully installed and is now entering the final assembly phase.

The third runner for the domestication and upgrade project of the Dachaoshan hydropower units in Yunnan Province, developed and supplied by Dongfang Electric Corporation, is currently being lifted into place

"We have broken away from the conventional technical approach that requires replacing components such as the head cover and guide vanes. By replacing only the runner, we have significantly enhanced the unit's wide-load operational capability, offering a valuable reference for similar retrofit projects." said Cheng Huan, Deputy Director of Dongfang Motor's R&D Center.

The Dachaoshan Hydropower Station is located on the middle-lower reaches of the Lancang River in Yunnan Province and represents the fourth stage of the 'Two Reservoirs, Eight Cascades' development plan. It is equipped with six 225-megawatt Francis hydroelectric generating units. The original runners were designed overseas and manufactured by Dongfang Motor, with full commercial operation commencing in 2003. In March 2020, Dongfang Motor won the bid to retrofit all six units at the station, initiating the comprehensive renewal effort.

In April 2022, the first domestically developed wide-load turbine was commissioned, meeting all technical specifications and setting an industry benchmark. The second new runner entered service in January 2025. The third runner is currently in the final assembly phase and is expected to be commissioned in April 2026.

As renewable energy capacity continues to expand, hydropower units are required to play a deeper role in peak load regulation and frequency modulation, demanding higher levels of stability across a wide load range. Dongfang Motor, in collaboration with Yunnan Dachaoshan Hydropower Company and Kunming University of Science and Technology, innovatively developed a hyperbolic Francis runner through numerical analysis and model testing. This design significantly improves hydraulic stability and structural strength while effectively reducing pressure pulsation and stress amplitude, enabling stable operation across the full load spectrum.

Based on these advancements, the team completed the research project titled "Key Technologies and Applications for Wide-Load Stable Operation of High-Specific-Speed Francis Hydro Units in New-Type Power Systems", establishing a comprehensive core technology system. The outcomes were evaluated by experts as internationally leading and were awarded the Second Prize of the 2025 Power Innovation Award.

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