On July 2nd, a colossal machine embodying the pinnacle of Chinese hydropower equipment technology set off from Harbin Electric Machinery Co., Ltd. (hereinafter referred to as Harbin Electric Machinery) of Harbin Electric Group Corporation. The core component of the world's first single-unit capacity of 500 megawatts and the largest runner diameter of 6.23 meters for an impulse turbine - the runner - was independently developed and delivered by Harbin Electric Machinery, marking a historic breakthrough in China's core equipment field for high-head, large-capacity impulse turbine units.
This turbine will be applied to the Zala Hydropower Station in Tibet. The Zala Hydropower Station was constructed by Datang Tibet Energy Development Co., Ltd. It is a key project of the "Electricity Transmission to the Outside of Tibet" of the country and the world's most challenging impulsive hydropower project under construction. The power station has two 500-megawatt impulsive generators with the largest single-unit capacity and the highest technical difficulty in the world. As the first (and only) major technological equipment project in the energy field of the National Energy Administration, this unit has technical features such as high altitude, high water head, and large capacity. It is the main model to serve the national strategy of "accelerating the construction of the hydropower base in the southwest".
The water chamber-type runner of the impulse turbine, as the core component of the unit, plays a crucial role in converting the kinetic energy of water flow into mechanical energy, and can be regarded as the "heart" of the hydroelectric generator set.
The Zara runner wheel has extremely high requirements for structural parameters, hydraulic performance and manufacturing techniques, representing the cutting-edge technological level of current impact-type hydroelectric generators. Harbin Electric Machinery has specially designed a high-performance water bucket-type runner for the Zara impact-type unit. This runner is composed of 21 precise water buckets, with an outer diameter of 6.23 meters, a total wheel height of 1.34 meters and a weight of approximately 80 tons. Its core component - the hub forging - is the largest martensitic stainless steel forging in the world. These breakthrough parameters indicate that this runner has achieved disruptive improvements in hydraulic performance, efficient operating range and pressure-bearing capacity in the industry.
As the pinnacle of world hydropower technology, the development process of this runner can be regarded as a model of systematic engineering innovation. The research team of Harbin Electric Motor has started from aspects such as the safety and performance of the unit, comprehensively considering the precise matching of the water bucket and the nozzle, the consistency of the jet diameter and efficiency, the interaction between the jet and the water bucket, the interference effect of adjacent jets of multiple nozzles, and the rigidity and strength indicators of the water bucket. Relying on the impact-type hydropower test bench of the National Key Laboratory of Hydropower Equipment, they innovatively integrated computational fluid dynamics flow analysis, high-speed photography and flow state observation techniques. Through continuous optimization, they ultimately achieved the ultimate design of the flow parameters.
It is known that the entire research and development process lasted for four years and went through five reviews. The research team systematically evaluated over a hundred schemes and manufactured six observation rotors with different design directions and six performance test model rotors. These were verified by a high-precision impact test bench. Their optimal efficiency and weighted average efficiency both set new world records, providing a solid guarantee for the safe, efficient and stable operation of the unit.
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