The installation of high-voltage DC circuit breaker demonstration application project in Nanao is the first batch of "Made in China 2025" major landmark projects of the National Energy Administration. The project adopts a scientific and technological innovation model of "production, learning, research, and use", aiming at the DC of multi-end flexible DC transmission system. The side faults quickly cleared the problem. The China Southern Power Grid Corporation, Huazhong University of Science and Technology, and Siyuan Electric Co., Ltd., have for the first time developed 160 kV mechanical HVDC circuit breaker equipment. It is based on coupled high-frequency artificial zero-crossing technology to realize bi-directional DC current breaking. It has simple control and high reliability. It has bi-directional breaking capacity of 0~9 kA and the breaking time is about 3.5 milliseconds. Under complex outdoor island conditions such as salt, high humidity, and strong wind, the area is only 34 square meters, and its overall technology has reached the international advanced level, which is of great significance for China to seize the high ground of the high-end electrical equipment manufacturing industry.

First, autonomously pioneering the topology and pushing mechanical HVDC breakers into reality. South Australia's 160 kV mechanical high-voltage DC circuit breaker is the world’s first mechanical high-voltage DC circuit breaker for engineering application. To eliminate intellectual property risks, it uses its own advanced advanced topology to overcome the traditional mechanical DC circuit breaker high-voltage pre-storage energy, High-voltage rapid triggering, rapid breaking and other technical problems, the rapid opening and breaking of high-voltage DC current of a hundred years of dreams into reality.

Second, the technical and economic advantages are prominent and help promote the flexible DC power grid. South Australia 160 kV mechanical high-voltage DC circuit breakers are mainly based on mature and static power equipment components, and all components have been fully domesticated. Compared with the hybrid HVDC circuit breakers of the same voltage class, it has the advantages of high reliability, low loss, low cost, small footprint, and direct outdoor layout, which greatly reduces the cost of construction, operation, and maintenance. Promote the development of a flexible DC grid.

Relying on China Southern Power Grid's multi-terminal flexible DC transmission system platform, China has realized the first demonstration application of mechanical HVDC breakers. The project team has overcome the rapid fault location technology of multi-terminal flexible DC transmission system with DC circuit breakers, and can complete DC-side fault location in 2 milliseconds, and achieve rapid isolation of the third station and DC line faults through DC circuit breakers, avoiding The complete stop of the multi-end flexible DC transmission system satisfactorily solved the existing problems of on-line switching and fault removal of the DC line at the third station of the existing South Australian multi-terminal flexible DC system, effectively improving the flexibility and reliability of the multi-terminal flexible DC transmission system in Nanao. .

In recent years, China Southern Power Grid Corporation has vigorously implemented innovation-driven development strategies, always regarded science and technology innovation as the primary driving force for development, and mastered core technologies in UHV DC, flexible DC, and large AC/DC power grids, and fully achieved international leadership. Significantly increased the technological content of China's power grid. At present, China Southern Power Grid Corporation has thoroughly implemented the spirit of the Nineteenth Party Congress, accelerated the construction of innovative companies, combined with the needs of the power grid development strategy, and promoted the development and implementation of major equipment through the implementation of key projects to promote the development of “Made in China” and new equipment industries. The successful operation of the 160 kV mechanical HVDC circuit breaker in South Australia provides better protection for the integration of new energy sources such as wind power, and provides a more economical solution for the development of the new equipment industry for DC circuit breakers. Transmission and application of future DC grid technology provide demonstration and reference.

(Original title: The world's first mechanical HVDC breaker was put into operation in South Net)