New breakthroughs have been achieved in the research on key technologies for external insulation of power transmission and transformation equipment in high-altitude areas of Qinghai Power Grid

On April 8, the "Key Technology Research on External Insulation of High-altitude ±800 kV (±1100 kV) DC Ultra-High Voltage Transmission and Transformation Equipment" project led by State Grid Qinghai Electric Power Research Institute successfully passed the acceptance.
The results of this project are a major breakthrough in the research on key technologies for external insulation of power transmission and transformation equipment in high-altitude areas around the world. They will be directly applied to the construction of domestic high-altitude DC and ultra-high voltage power transmission and transformation projects to efficiently serve clean energy transmission and transmission channel structure optimization.

It is understood that with the construction of the national Shago Desert Clean Energy Base, construction of new UHV clean energy transmission projects such as Jinshang-Hubei, Longdong-Shandong, Hami-Chongqing, Ningxia-Hunan has started, with multiple routes and UHV power transmission channels starting in Qinghai Province have also been deployed and planned. UHV has become an important means to promote the optimal allocation of energy resources and promote the accelerated development of clean energy.

According to Wang Shengfu, project leader of the State Grid Qinghai Electric Power Research Institute, in high-altitude areas, the climate environment is complex and the air is thin, and the gap discharge voltage will gradually decrease as the altitude increases, bringing many problems to the construction and operation and inspection of UHV projects. Problems. On the one hand, with the increase of altitude, the insulation strength of the air gap will become more prominent with the characteristics of supersaturation and large dispersion. If the end fittings in low altitude areas are simply enlarged, it will not be possible to meet the requirements for clear air distance value. It is necessary to accurately calculate the increase ratio of the gap size to ensure its safety and economy; On the other hand, there is currently no long-term operation experience of ±800 kilovolt UHV DC projects in high-altitude areas in China, insufficient accumulation of live working technology, and no experience in commissioning ±1100 kilovolt UHV DC projects.

The reporter learned that in the absence of corresponding scientific research results, design specifications, and engineering and design experience, in order to ensure the safe operation of ±800 kV and ±1100 kV transmission lines in high-altitude areas, the State Grid Qinghai Electric Power Academy took the lead and collaborated with China Electric Power Research Institute Co., Ltd., State Grid Qinghai Province Power Company Ultra-High Voltage Company, and the Equipment Management Department of State Grid Qinghai Electric Power Company for three years. The "Research on Key Technologies for External Insulation of High Altitude ±800 kV (±1100 kV) DC Ultra-High Voltage Transmission and Transformation Equipment" project was carried out.

The research results of this project have systematically obtained the corona initiation characteristics of typical shielding fittings in valve halls and DC fields of high-altitude UHV converter stations, optimized the size parameters of the converter station's shielding fittings, and provided important technical support for the optimal design and configuration of external insulation for UHV DC power transmission and transformation projects in high-altitude areas in China.

"This project has carried out relevant characteristic tests in high-altitude areas to obtain the discharge characteristics of various insulation gaps in high-altitude areas, providing a basis for the configuration of external insulation in high-altitude areas, providing safe distances for live working, minimum effective lengths of insulating tools and appliances, etc. Recommended values are provided." Wang Shengfu said that the project results will serve the construction, operation and maintenance of DC UHV power transmission and transformation projects in high-altitude areas, and play an important role in building a clean energy industry highland in Qinghai Province.

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