Recently, the State Grid Shanghai Municipal Electric Power Company (SMEPC) has successfully completed its annual maintenance work for the ±500kV Nanqiao Converter Station.
The most crucial task is to conduct a comprehensive initial inspection of the "Chinese Heart" -- the world's first controllable line - commutated converter (CLCC) with full independent intellectual property rights inside the converter station, further improving the health level of the equipment and laying a solid foundation for reliable power supply during this year's peak electricity consumption in the summer season.
The Nanqiao Converter Station, commissioned in 1989, serves as the receiving end of the nation's inaugural commercial DC transmission project, the Gezhouba- Shagnhai Nanqiao (Ge'nan) DC. It boasts a maximum transmission power of 1.16 million kilowatts and a maximum transmission capacity of approximately 8.2 billion kilowatt hours in a year. It serves as a vital entry point for clean hydroelectric power from the Southwest to Shanghai.
In June 2023, SMEPC undertook a comprehensive technical upgrade of the core components at Nanqiao, transitioning from fully imported to domestically produced equipment. This involved replacing the conventional converters, which were originally imported, with CLCC, addressing the persistent issue of "commutation failure" that impacted the station's operational reliability, thereby significantly enhancing the operational reliability of Shanghai's primary power grid.
"Since its operation, 'Chinese Heart' has been operating well, successfully avoiding six 'commutation failures' caused by power grid fluctuations, withstanding the test of continuous high loads in summer and winter, and significantly improving operational reliability compared to the original imported converters. This first inspection is not only a 'comprehensive physical examination' of the equipment, but also will accumulate valuable experience for the continuous and safe operation of the equipment in the future," said Zhu Zhengyi, director of Nanqiao Converter Station.
It is reported that CLCC, the colossus within the converter station, is assembled from nearly 10,000 components and is among the most precise and intricately structured power equipment. To ensure the high-quality completion of this initial inspection work, State Grid Shanghai ExtraHigh Voltage Company has summarized and analyzed the operating data of the CLCC since its commissioning, tailored maintenance plans, and formed a "core team" composed of model workers, senior experts, and other technical backbone members, which can solve "difficult and miscellaneous problems" encountered during the maintenance process at any time.
Based on the on-site arrangements, the annual inspection of Nanqiao Converter Station and the initial inspection of CLCC were divided into eight work categories, with a total of 151 tasks accomplished. Nearly half of the maintenance and technical renovation tasks are associated with CLCC. SMEPC ensures that maintenance work is flawless through strict on-site control and quality supervision, complemented by digital methods such as big data analysis and simulation operations.
"The CLCC technology represents a revolution in traditional DC transmission technology. SMEPC will effectively utilize and adapt this internationally-leading innovation, guiding industrial innovation with technological advancements, and actively transitioning research outcomes from the laboratory to the front lines of power grid operations. Tailoring strategies to local conditions, we aim to foster new quality productive forces, thereby providing robust power support for Shanghai's development of its 'Five Centers' initiative," said Lu Zhihao, deputy director of the Equipment Department at SMEPC.
(Source: State Grid Shanghai Municipal Electric Power Company)
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