SerpApi.Org
A major part of the world’s first 500-megawatt impulse hydropower unit has reached an important engineering milestone in southwest China. Recently, the inlet spherical valve for Unit 1 at the Datang Zhala Hydropower Station in Xizang passed its hydrostatic pressure test, demonstrating that its seal operates as designed under all conditions.
According to a report by Securities Times, the successful test marks the end of on-site assembly and testing for the first large-inlet spherical valve at the hydropower station.
The Zhala project is the first approved megawatt-level hydropower project in Xizang. It is also set to become a key power source for China’s national clean energy demonstration base, which brings together hydropower, wind, and solar energy in southeastern Xizang.
Giant valve clears critical pressure test
The spherical inlet valve is a crucial safety component in a high-head hydropower plant. It manages the flow of water into the turbine and must handle very high water pressure while keeping a secure seal.
For Unit 1, the valve is 9.5 feet (2.9 meters) wide and is made to work at a pressure of 9 megapascals. It includes several main parts: the large valve body, the small valve body, the valve disc, and the valve shaft.
Once assembled, the valve body weighs more than 300 tons. According to Dongfang Electric Corporation, the successful hydrostatic pressure test confirms the valve can work safely under the tough conditions expected at the power station.
Built for the world’s first 500 MW impulse units
The Datang Zhala Hydropower Station will operate two 500 MW impulse hydropower units with Pelton turbines. Each unit can generate 500 MW and is designed to operate under high-head conditions at high altitudes.
Dongfang Electric is in charge of researching, developing, and supplying one full generating unit. According to the company, the project has been included in the National Energy Administration’s first group of major technical equipment projects for the energy sector.
It is currently China’s only hydropower project that is conducting research, development, and demonstration of 500-MW-class high-head, large-capacity impulse hydropower units. The company also calls it the world’s most technically challenging impulse hydropower project currently under construction.
The project is expected to help develop new technologies for future large-scale hydropower projects in similar conditions.
Open-air assembly posed major engineering challenges
Installing the huge valve needed a different method than the usual factory assembly. Rather than assembling it in the workshop, the whole spherical valve was put together outside the assembly yard. Engineers had to deal with limited space, tight lifting areas, and changing weather during the installation.
According to Dongfang Electric, these conditions significantly increased the complexity of the work compared with standard assembly methods. The company said that designing, making, and installing the valve has raised the industry’s technical abilities for main inlet spherical valves.
The successful completion of the pressure test is also expected to boost China’s capabilities in manufacturing key components for high-head, large-capacity impulse hydropower units.
The company added that the achievement will “propel China’s research and development capabilities for core components of high-head, large-capacity impulse hydropower units to a new level.”
