The world's first high-voltage, large-capacity, low-frequency conversion station was successfully put into operation-NR Electric Co. Ltd

The world's first high-voltage, large-capacity, low-frequency conversion station was successfully put into operation

Tingshan Frequency Converter Station of Hangzhou Flexible Low Frequency Transmission Pilot Project has been officially put into operation. It is the first time in the world to realize 220kV voltage level power frequency and low frequency controllable transformation.

Flexible low-frequency transmission is a new type of AC transmission technology whose frequency is lower than the power frequency, which can effectively improve the transmission capacity, distance and efficiency of transmission lines. It has certain application advantages in medium and long distance offshore wind power transmission.

In order to optimize the power grid layout in Hangzhou, and explore the application prospect of flexible low-frequency transmission technology in urban high-density load areas, State Grid Zhejiang Company has planned and built Hangzhou flexible low-frequency transmission Pilot project in Hangzhou.

The two high-voltage and high-capacity frequency converter stations in Tingshan and Zhongbu constructed in the project will form flexible low-frequency interconnection, which can realize flexible power flow mutual aid and asynchronous interconnection of the two major power grids in Fuyang and the south of Xiaoshan, improve the transmission capacity and flexibility of the two major power supply sections of 500kV Fuyang substation and 500kV Shengguang substation, improve the security and stability of the regional power grid.

Tingshan Frequency Converter Station is the first high-voltage and high-capacity low-frequency converter station in the world, and also an important part of Hangzhou flexible low-frequency transmission project. The NR project team has tailored flexible low-frequency protection & control system, frequency conversion valve, low-frequency AC protection device, measuring equipment and other core complete sets of equipment for Tingshan frequency conversion station. In view of the high voltage and large capacity application scenario of Hangzhou Flexible Low Frequency Transmission Project, the project team put forward efficient start stop control strategy, steady state control strategy, low-frequency open phase operation control strategy, fault ride through strategy, frequency converter protection strategy and low-frequency AC protection scheme, which solved many problems such as low-frequency decoupling control, bridge arm balance control, fault current suppression, low-frequency open phase operation, etc. At the same time, the project team overcame the problems of synchronous pressurization of converter valve at power frequency and low-frequency, completed the insulation test between high-voltage and high-capacity frequency converter valve power frequency and low-frequency terminals for the first time.

To build an advance power system with renewable energy as the main body has become the main development direction of the power industry. As a key high-tech enterprise, NR has carried out fruitful research and exploration in the field of building an advance power system. The complete set of flexible low-frequency equipment developed by NR has been successfully applied to Taizhou flexible low-frequency transmission project, and continues to serve the grid connected transmission of offshore wind power in Dachen Island. Hangzhou Flexible Low Frequency Power Transmission Project is an active attempt to apply flexible low frequency complete equipment to the construction of high elastic power grids in urban areas, and also provides a practical model for high-voltage and high-capacity offshore wind power transmission through low frequency. NR will continue to maintain high standards and quality to serve the project construction, give full play to its advantages, ensure the overall operation of the project, and continue to contribute to the construction of an advance power system.

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