Which technologies are essential for global energy interconnection?

China Energy Storage Network News : Global Energy Internet is a major breakthrough and integrated innovation in modern energy and power technology. Its essence is "smart grid + UHV grid + clean energy". The key to accelerating the construction of global energy Internet and improving the safety and economy of large power grid operation lies in technological innovation. UHV AC and DC transmission, flexible transmission, clean energy, energy storage, large power grid operation analysis and control and other technologies are the technical fields that need to be focused on research and development at present and in the future.

UHV AC technical equipment

In the second half of the 1960s, the United States, the former Soviet Union, Japan, Italy and other countries successively built UHV test stations and test lines, but most of them remained in the test stage or stepped-down operation and were not put into commercial operation. In recent years, China's UHV AC technology has developed rapidly, and the key technologies of 1000 kV UHV AC (including system voltage control, sub-supply current suppression, external insulation coordination, electromagnetic environment control, etc.) and complete sets of equipment with completely independent intellectual property rights have matured and been widely used in engineering.

China has developed the world's first 1100 kV controllable shunt reactor and the world's largest 400 Mvar/1100 kV UHV reactor, the world's first 1500 MVA field-assembled transformer prototype, and the world's first UHV gas-insulated transmission pipeline.

UHV DC technology equipment

From the commissioning of China's first ±800 kV UHV DC transmission project to the present, key UHV DC technologies (including overvoltage and insulation coordination, external insulation configuration, electromagnetic environment and noise control, DC system design, etc.) and complete sets of equipment have matured and have been widely used. On this basis, we are moving towards ±1100 kV UHV DC technology.

At present, China has developed a ±1100 kV DC gas-insulated wall bushing prototype, made breakthroughs in the key technologies of ±1100 kV UHV DC converter valve complete set design and testing, and developed the world's first ±1100 kV/550A UHV DC converter valve. The development level of key technical equipment such as DC cables, DC bushings, and converter transformers has continued to improve.

Clean energy technology equipment

Since the 1970s, countries around the world have accelerated research on clean energy development and utilization and grid-connected operation technologies.

In terms of wind power generation, onshore wind power technology has become relatively mature, offshore wind power has begun commercial operation, and the capacity of a single unit has reached 8 megawatts. High-altitude wind power generation systems have also begun to be developed. The latest high-altitude wind power system has a power of 600 kilowatts. Direct-drive technology, variable-pitch and variable-speed power regulation technology and full-power conversion technology have been applied.

In photovoltaic power generation, the efficiency of monocrystalline silicon solar cells can reach up to 25%, and that of polycrystalline silicon solar cells can reach up to 20%; the efficiency record of thin-film solar cells has also reached 22.3%. In solar thermal power generation, the solar concentrator field system can reach up to 200,000 mirrors, the main steam parameters of trough units can reach about 380 degrees Celsius, and the working fluid parameters of tower units can reach about 500 degrees Celsius.

In terms of ocean energy power generation, a number of experimental prototypes and engineering prototypes have been developed internationally, and application tests have been carried out; tidal power stations have achieved commercial operation, and tidal energy and wave energy technologies have a foundation for demonstration and application.

In terms of grid-connected operation, China has mastered core technologies for new energy power generation control, such as resonance suppression of multiple photovoltaic machines connected to the grid, and completed the development of a virtual synchronous machine prototype.