China recently announced the activation of the world’s most powerful smart direct current (DC) transformer, enhancing its power grid capabilities. This significant development, revealed in late 2025, comes as part of China’s ongoing efforts to improve electricity transmission and accommodate renewable energy sources.
The new transformer, rated at an impressive 750 million volt-amps (MVA), was manufactured by Changzhou Xidian Transformer. Unlike traditional alternating current (AC), DC is more efficient for transmitting large quantities of electricity over long distances. This latest unit is classified as “smart” due to its advanced real-time control systems. These systems enable operators to adjust key parameters such as current, temperature, and voltage dynamically.
Addressing Challenges in Power Transmission
The introduction of this transformer is particularly timely, given the challenges faced by China’s northwest power grid. In fall 2024, the region experienced a significant failure attributed to “low-frequency power oscillation.” This phenomenon involved fluctuations in electricity supply and demand, jeopardizing the stability of the grid, especially in the Xinjiang region, which hosts some of the largest wind and solar farms globally.
Wind and solar energy production is inherently variable, influenced by weather conditions. For instance, solar panels generate less energy on cloudy days, while wind turbines rely on specific wind speeds to operate effectively. This variability necessitates robust power converter stations capable of balancing supply and demand, making the new transformer essential for maintaining grid stability.
The previous generation of high-voltage direct current (HVDC) transformers, with a capacity of 587.1 MVA, set records at their time of installation but now fall short compared to the current unit. The new 750 MVA transformer is a crucial upgrade that addresses earlier limitations and strengthens the overall reliability of the power grid.
Renewable Energy and Grid Limitations
China’s ambitions to expand renewable energy have seen considerable success, but the ability to effectively integrate this energy into the power grid has emerged as a pressing concern. In 2025, certain regions were unable to utilize all the electricity generated, prompting government officials to limit output in specific areas. This situation highlights a critical need for infrastructure that supports not only generation but also efficient distribution.
As China continues to invest in renewable energy technologies, the integration of smart transformers like the new 750 MVA unit will play a vital role in future-proofing the nation’s energy infrastructure. By improving the stability and reliability of long-distance power transmission, this innovation positions China to better manage the complexities of a rapidly evolving energy landscape.
