On December 30, 2020, after 168 hours of trial operation, Qinghai-Henan ± 800kV UHVDC transmission project was officially put into operation.
The Qing-Henan project is the first UHVDC project built for clean energy outsource in China. It is an important measure to achieve China's commitment to carbon peak in 2030 and the carbon neutral target in 2060.
The project starts from Hainan Prefecture of Qinghai Province and ends in Zhumadian area of Henan Province. It passes through Qinghai, Gansu, Shaanxi and Henan provinces. The total length of the line is 1587 km and the transmission capacity is 8 GW. After it is fully put into operation, it can transmit 40TWh of green and clean power to Henan every year, which has greatly promoted the development and utilization of renewable energy in the south of Qinghai Province.
NR provides a complete set of core equipment for Qing-Henan project, including HVDC converter valve, protection & control, valve cooling tower, synchronous condenser secondary system, measurement system, DC voltage divider, stability control system, AC protection, CAFS control system, fire automation, grounding electrode online monitoring , etc.
NR has comprehensively researched and developed the key technology of UHVDC transmission application in high altitude areas. As the only UHVDC transmission project in the world that mainly transports photovoltaic, wind power and other renewable energy, the overvoltage of power at the sending end will seriously affect the stability of power grid and limit the transmission capacity of DC.
Aiming at this problem, NR has carried out a number of special protection & control strategy studies, and carried out more than 300 verification tests, which ensured the safety & reliability and made the new strategy become the "centering agent" for the stable operation of Qing-Henan DC project.
In view of the special harsh environment of high altitude and severe earthquake magnitude where Qingnan converter station is located, the converter valve system experts have carried out a special project to optimize the design, check the primary and secondary equipment from the main parameters, insulation, heat dissipation, electric field and other aspects. All products have passed the third party verification, which provides a solid technical guarantee for the reliable output of renewable energy.
The valve cooling system developed by NR provides stable and reliable cooling support for the converter valve. The new design reduces the site area, makes the maintenance convenient and the service life of the equipment long.
NR provides a complete secondary solution for the 4 sets of * 300Mvar synchronous condenser, which optimizes and improves the integration of synchronous condenser monitoring and DC protection & control, reactive power coordination control between the condenser and DC protection & control, overcomes the problem of long-distance transmission of renewable energy, significantly improves the convenience of operation and maintenance in the station, and improved the dynamic reactive power support capacity of condenser.
In order to adapt the flexible operation mode of AC power grid, aiming at the characteristics of high proportion of renewable energy in power grid, the stability control system adopts the scheme of region, type and multi resource collaborative optimization to ensure the delivery and consumption of clean energy to the maximum extent.
NR PCS-9119CAFS fire linkage control system can realize the automatic start of the compressed air foam spray and firefighting system in the whole station and the equipment monitoring.
The successful implementation of Qing-Henan project shows the technical advantages of multi-disciplinary integration and the implementation ability of team cooperation of NR, highlights the outstanding comprehensive strength of NR in the field of UHV equipment in high altitude and cold regions.
NR will continue to research and provide reliable and flexible HVDC soluton for our customer.