State Grid's Zhejiang branch leverages science and technology to help solve peak summertime electricity load

Personnel from a low-frequency operation and inspection team conduct routine inspections of the water-cooling system of the frequency converter in the Yanchang Substation of Taizhou 35 kV Flexible Low-Frequency Transmission Demonstration Project, May 22, 2023. (Photo provided to People's Daily Online)

The operation and maintenance personnel conducted optimal inspection of low-frequency equipment in the Yanchang Substation of Taizhou 35 kV Flexible Low-Frequency Transmission Demonstration Project, and recorded the parameters of low-frequency equipment such as temperature, pressure, and humidity on May 22. This process facilitated the preparation of regional supply of electricity earmarked for the summertime spike in electricity. The project has operated steadily and reliably for one year, transmitting nearly 7 million kWh of electricity generated from offshore wind energy.

In June 2022, the project, the first of its kind in China, was put into operation, creating the inaugural frequency reduction and direct transmission of clean energy at sea. Multiple sets of new equipment, such as M3C frequency conversion valve, low-frequency circuit breaker, and control and protection device, have been applied to the demonstration project. The resulting formation of a "Land-Island-Wind Power" interconnection system converted the wind on Dachen Island into 20 Hz low-frequency alternating current continuously sent to the inland.

State Grid Zhejiang Electric Power Co., Ltd. has always promoted the research on cutting-edge technologies. By reducing transmission frequency, improving transmission capacity and increasing transmission distance, the company greatly reduced the investment, operation, and maintenance costs of power transmission equipment for islands.

Not only does the project actuate efficient utilization of surplus wind power resources in islands, but it also provides "double insurance" for power supply in Dachen Island. After it was put into operation nine months ago, the project has been running smoothly. A total of 2,763,300 kWh in accumulated offshore wind energy has been transmitted. Forecasted to generate electricity with a capacity of 4.5 million kWh annually, equivalent to the annual electricity consumption of 2,000 households, this project can save 1,800 tonnes of standard coal and reduce carbon dioxide emissions by 4,480 tonnes every year.

Facing the technical challenges resulting from the construction of new power system, the company has, in recent years, prioritized its philosophy of scientific and technological self-reliance. Apart from planning the resolution of key technical problems, it also focused on leading demonstration project research, building a high-level R&D platform, establishing 21 laboratories at all levels, offering full play to the advantages of the Industry-University-Research power system, enhancing the experimental research ability in emerging fields, and producing numerous landmark scientific and technological innovations in the core links of new power system construction such as virtual power plants, hydrogen-electricity coupling, and new energy storage.

Upon becoming cognizant of the “power plus quantum” field, the company has carried out comprehensive research on quantum application in the power field. By deploying "wireless public network plus quantum encryption" technology, some areas in Zhejiang, such as Xinchang in Shaoxing and Hengdian in Jinhua, can effectively realize the flexible regulation of new power systems. As a result, the enhancement of the power grid’s power supply capacity can address the peak electricity load this summer.