On December 20, the world's first mechanical HVDC circuit breaker was successfully put into operation in the ±160kV Nanao multi-terminal flexible DC transmission system of China Southern Power Grid. It is based on coupled high-frequency manual zero crossing technology to achieve rapid switching of two-way DC current, its control is simple, high reliability, and its overall technology has reached the international leading level, which is of great significance for China to seize the commanding heights of high-end electrical equipment manufacturing industry.

This is China's first fully self-developed mechanical HVDC circuit breaker equipment for flexible DC transmission system, and its successful operation is another important milestone in China's continuous innovation in the field of DC transmission.