Main body installation of China's first domestically produced variable-speed pumped storage unit completed

en.Wedoany.com Reported - On October 1, the rotor of the variable-speed unit at the Guangdong Zhaoqing Langjiang Pumped Storage Project was successfully hoisted, marking the completion of the main body installation of China's first domestically produced variable-speed pumped storage unit and accelerating the development of China's high-end energy equipment.

In the underground powerhouse of the Zhaoqing Langjiang Pumped Storage Project, a rotor nearly 5.2 meters tall and weighing 445 tons was steadily lifted and translated under the close coordination of crane operators and ground commanders, then slowly lowered into the foundation pit. The component hoisted this time was the last core functional part of the variable-speed unit, and the equipment weight, installation precision, and hoisting difficulty all ranked first among the unit's components. "This is the most difficult hoisting in a pumped storage project, and the hoisting precision must be controlled within a tolerance of 4.5 millimeters. Using a series of technical measures such as laser positioning and center calibration, we completed the hoisting in 6 hours," said He Zheng, manager of the Electromechanical Project Department of the Zhaoqing Langjiang Pumped Storage Project of Sinohydro Bureau 4 Co., Ltd.

In May 2022, the domestically produced variable-speed pumped storage unit installed at the Zhaoqing Langjiang Pumped Storage Project was officially included in China's list of first-of-its-kind major technical equipment in the energy sector. By changing its rotational speed by 7%, the unit can achieve real-time adjustment across 50% of its power range, more flexibly converting surplus electricity generated by wind and solar power into 280,000 cubic meters of stored water energy each hour and generating electricity steadily when the power system requires it.

After four years of technical design, equipment manufacturing, and on-site assembly, the unit has filled domestic technical gaps in multiple fields, including control system development, stable retaining ring manufacturing, and precision coil installation, achieving a localization rate of 100%. Take China's first AC pumped storage excitation system installed on the unit as an example: its capacity reaches more than 10 times that of conventional fixed-speed pumped storage units, breaking the long-term foreign technological monopoly. To stabilize the series of "impacts" on the equipment caused by variable speed under high-speed rotor rotation, the first domestically produced oversized-diameter non-magnetic metal retaining rings were installed at both ends of the rotor. Their material yield strength of 750 megapascals is equivalent to an area the size of a fingernail withstanding the pressure of three cars stacked together.

The successful hoisting of the rotor this time has advanced the engineering application of the variable-speed pumped storage unit into the final stage of functional commissioning. "Next, we will also carry out more than 50 tests to comprehensively verify the unit's performance and ensure quality control for the commissioning of China's first major energy technology equipment," introduced Zhao Lei, deputy general manager of the Zhaoqing Langjiang Pumped Storage Project Department of China Southern Power Grid Energy Storage Co., Ltd. At present, the construction of the Zhaoqing Langjiang Pumped Storage Project has entered the sprint stage before commissioning and is expected to be fully commissioned in the first half of 2027, with an annual capacity to absorb 2.16 billion kilowatt-hours of clean energy and a corresponding reduction of about 1.9 million tons of carbon dioxide emissions.