The Yarlung Zangbo River Hydropower Project is one of the largest hydropower projects in the world. Its complex geographical conditions (high altitude, large drop and strong geological activities) and long construction period (estimated to be more than 20 years) put forward extremely high requirements for the performance of pump equipment. Combining industry practice and engineering particularity, this project will involve the following core pump types and technical schemes:

First, the core pump equipment in the construction stage

1. Large-flow drainage and emergency rescue pump set

During the construction period, it is necessary to cope with the challenges such as water gushing in tunnel and water accumulation in foundation pit, and it is necessary to configure a diesel-driven double-suction centrifugal pump (such as YP series of Southern Pumps) and an emergency drainage pump truck, with a single flow rate of more than 2,000 m/h and rapid deployment capability. In view of the high altitude hypoxia environment, plateau diesel engine is needed, and the power compensation technology can keep the performance of the equipment above 80% at an altitude of 4000 meters.

2. High-lift multistage centrifugal pumps are used for construction water supply, concrete curing and equipment cooling. For example, CDM series multistage centrifugal pumps in Southern Pump Industry have a single-stage lift of 150 meters and a total lift of 600 meters, which can meet the vertical water supply demand of tunnels with a depth of 3,000 meters. Impeller is made of cavitation-resistant stainless steel (such as 316L), and with frequency conversion speed regulation technology, it can adapt to the working condition of flow fluctuation of 30%.

3. High wear-resistant slurry pump concrete mixing station needs to transport aggregate mortar. NKIH series slurry pump adopts bimetallic impeller and tungsten carbide coated volute, which can tolerate solid particles with particle size ≤50mm, and its service life is more than 3 times higher than that of ordinary pumps.

4. Long-axis deep-well pump, Zangmu Hydropower Station and other built projects require that the long-axis deep-well pump should have a rated flow of ≥ 650 m/h and a lift of ≥60m for pumping and draining the leakage water of underground powerhouse. This kind of pump needs bronze impeller and rubber bearing to adapt to the long-term operation of sediment-bearing water.

Second, the key pump system during the operation period of the power station

1. Special pump for auxiliary system of hydraulic turbine

Main shaft sealing pump: CDMF series multistage centrifugal pumps provide high-pressure sealing water of 0.8-1.2MPa for the main shaft of water turbine to prevent leakage between high-speed rotating shaft and guide bearing.

Technical water supply pump: NISF series single-stage centrifugal pump provides constant pressure cooling water for generator air cooler and transformer cooler, and the flow accuracy is controlled within 5% to ensure that the equipment temperature difference is ≤2℃.

2. High altitude environmental adaptive pump

Aiming at the altitude of 3100 meters in Linzhi area, it is necessary to use air pressure compensation submersible pump. For example, U-flo series products balance internal and external pressures through automatic air supply system to avoid cavitation, and the impeller wear is reduced by 70% compared with traditional pumps. At the same time, the cooling circulating pump should be equipped with plateau motor and adopt forced air cooling system, which can still run stably at the low temperature of-30℃.

3. DRL non-negative pressure water supply equipment is adopted in the domestic water supply system of intelligent energy-saving pump set, and water supply is realized on demand through the linkage of pressure sensor and frequency converter, and the energy-saving rate is over 35%. The TD pipeline circulating pump of heating and cooling system integrates the Internet of Things module, which can remotely monitor parameters such as vibration and temperature, and the predictive maintenance period is extended to 12 months.

4. Wear-resistant mixed-flow pump The average annual sediment transport capacity of Yarlung Zangbo River is 150 million tons, so it is necessary to use wear-resistant mixed-flow pump, such as the vertical volute pump developed by Dongfang Electric in Gaoxinsha Pumping Station. The blade profile is optimized by CFD and sprayed with ceramic coating, and the efficiency is kept above 85% under the condition of sediment concentration ≤ 5 kg/m.

III. Special Technical Challenges and Solutions

1. Reliability design under extreme working conditions

For the ultra-high-speed water flow of 16m/s at a big bend, it is necessary to adopt a centrifugal pump with double volute, the outer pressure-bearing shell is made of high-strength ductile iron, and the inner flow channel is lined with ultra-high molecular weight polyethylene, which can withstand instantaneous pressure impact up to 10MPa.

2. Environmental protection and ecological protection requirements The fish multiplication station needs a low shear axial flow pump. For example, VTM series products are designed with large blade spacing, and the fish passing rate is ≥95%. At the same time, WQ series sewage pump of sewage treatment system is equipped with oil-water separation device, and the oil content can be reduced to below 10ppm.

3. All pumps in the intelligent operation and maintenance system are connected to the intelligent pump station management platform. Through AI algorithms such as vibration spectrum analysis and energy efficiency monitoring, the fault early warning accuracy is ≥90%, and the energy consumption optimization range is 15%-20%. For example, by predicting the wear cycle of guide bearings through machine learning and changing the planned maintenance into condition-based maintenance, the downtime can be reduced by more than 400 hours every year.

Fourth, industrial chain coordination and localization breakthrough

The project will promote the upgrading of domestic pump technology. For example, the stainless steel centrifugal pump of Lingxiao Pump Industry has passed the CE certification of the European Union, accounting for 15% of the hydropower station market in Southeast Asia, and it is expected to undertake cross-border power transmission supporting projects. The pump technology of Dongfang Electric's high-tech sand pumping station has achieved 15m/s super-large flow transportation, and its hydraulic efficiency has reached the international advanced level, which will be extended to the field of multi-stage pumps in the future. Core patents such as air pressure compensation technology and anti-abrasion coating technology of plateau pumps will form independent intellectual property barriers and break the monopoly of foreign brands in the high-end pump market.

To sum up, the demand for pump equipment in Yarlung Zangbo River hydropower project is characterized by "high parameters, multi-scenarios, intelligence and localization". It is estimated that the total procurement scale will exceed 5 billion yuan, involving more than 80 specifications in 12 categories, including centrifugal pumps, axial flow pumps and mixed flow pumps. The relevant technical breakthroughs will provide a benchmark example for the development of high-altitude hydropower in the world. (This article is from Daodao www.seetao.com, official website. It is not allowed to reprint without permission, otherwise it will be prosecuted. Please indicate Daodao. com+original link for reprinting.) See Editor of Daodao. com Infrastructure Project/Wang Xia.