On September 23, the first runner of the "Dongfang Blue Lotus," the core component of the world's largest single-unit capacity 500 MW Pelton turbine unit independently developed by Dongfang Electric Machinery Co., Ltd. (hereinafter referred to as "Dongfang Electric Machinery"), a subsidiary of Dongfang Electric Corporation, was officially delivered and will be applied to the Datang Zala Hydropower Station in Tibet.
It is reported that more than 90% of the runner's manufacturing process has been digitized and intelligentized, with manufacturing precision reaching the industry-leading level, and all data indicators meeting the premium quality standards. The completion of the full set of equipment development for the unit marks a new breakthrough for China in the field of core equipment for high-head, large-capacity Pelton turbine units.
The runner of the world's largest single-unit capacity 500 MW Pelton turbine unit independently developed by Dongfang Electric Machinery. Photo courtesy of Dongfang Electric Corporation
The Datang Zala Hydropower Station features high head, large capacity, and high altitude, and is equipped with two 500 MW Pelton turbine units. Dongfang Electric Machinery is responsible for the development and supply of Unit 1 of the station. The Datang Zala project has been selected as a first-of-its-kind major technical equipment project in the energy sector by the National Energy Administration. It is the only hydropower project in China capable of carrying out the development and application demonstration of 500 MW-class high-head, large-capacity Pelton turbine units, and is also the most comprehensively difficult Pelton hydropower project currently under construction in the world.
As the core flow-passing component of a hydropower unit, the runner's main function is to efficiently convert the kinetic energy of water flow into rotational mechanical energy, directly determining the unit's flow-passing capacity, hydraulic efficiency, and operational stability. The Zala runner rolled off the production line this time has an outer diameter of approximately 6.2 meters, a thickness of approximately 1.3 meters, and a weight of approximately 80 tons. It innovatively adopts a composite forging and welding structure of "central body forging + tail fin additive manufacturing + external bucket die forging," comprehensively ensuring the structural and performance quality of the product.
In the manufacturing stage, Dongfang Electric Machinery innovated the "central body forging + composite additive manufacturing" production model, developed high-performance "laser + arc" additive manufacturing technology, reduced the forging thickness by nearly one-third, and significantly lowered the internal quality risks of large-thickness forgings. At the same time, it applied strongly constrained spatial robotic welding technology, overcame the challenge of automatic robotic welding of complex curved surfaces, greatly improved weld performance and process stability, and achieved a post-weld first-time flaw detection qualification rate of over 99%. It also developed a new coupled anti-sediment abrasion technology, carried out targeted design based on sediment abrasion mechanisms, and provided a brand-new solution for the runner's resistance to sediment abrasion. It exploratorily applied robotic grinding technology for the grinding of complex curved surfaces of the buckets, improving the profile quality of the buckets.