Renewable Energy China Develops the World's Largest Direct Current Transformer

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A calm day almost led to a nationwide blackout. A year later, Chinese engineers have introduced an "intelligent transformer" designed to better integrate renewable energy into the power grid in the future.

The Chinese manufacturer Changzhou Xidian from Jiangsu Province announced in mid-December 2025 that it had developed a high-voltage direct current transmission transformer with a capacity of 750 million volt-amperes. According to the Chinese specialist portal Jinbaonet, it is the world's largest HVDC transformer, built using a series of proprietary technological innovations.

On August 3, 2024, strong fluctuations in the feed-in of wind power in the western Chinese region of Xinjiang nearly caused a nationwide blackout. Such incidents are to be prevented in the future by increasingly transporting electricity via flexible direct current transmission.

"The technology can effectively address the instability associated with a high share of renewable power generation on the feed-in side," writes Jinbaonet. Additionally, it improves the safety, stability, and operational flexibility of large power grids.

Transformer Remains Stable Even Under Extreme Conditions

The transformer converts alternating current, where the direction of current periodically changes, into direct current. The company stated that its developers had implemented innovative methods for controlling magnetic stray fluxes and for temperature monitoring using fiber optic technology. During tests, the system remained stable even under extreme conditions, such as simulated lightning strikes.

China has begun building massive solar and wind farms in the sun- and wind-rich deserts in the north of the country. The electricity is then transmitted via ultra-high voltage lines, known as UHV corridors, to the densely populated and "energy-hungry" coastal regions in the east of the country.

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Transport Electricity Over 1,243 Miles

The newly completed transformer was developed for the national west-east power transmission project, which transports electricity over 1,472 miles from Gansu Province to the coastal province of Zhejiang.

After commissioning, around 36 billion kilowatt-hours of green electricity are expected to flow annually, transmitted via direct current and at ultra-high voltage.

China is rapidly increasing the share of wind and solar power in its energy mix. Similar to other countries, grid operators face the problem of highly variable feed-in, as sun and wind do not provide reliable power levels throughout the day or across seasons. Additionally, green electricity cannot always be generated where it is most urgently needed.

The new facility is regarded in expert circles as evidence of the technological advancements of Chinese manufacturers in the energy sector.

Expand the Network of UHV Lines Further

A central part of the solution is the rapid expansion of an extensive network of UHV lines that spans China from west to east and from north to south.

With the help of these UHV lines and modern HVDC technology, renewable energy can be transported over long distances with comparatively low losses.

The new facility is regarded in expert circles as evidence of the technological advancements of Chinese manufacturers in the energy sector. In 2018, China ordered and imported a comparable transformer with 1,100 kilovolts and 12 gigawatts from Siemens. Today, China develops and builds such facilities itself and continues to improve them, experts say.

Several Reasons for Investing in Modern Energy Systems

China is investing heavily in modern energy systems for several reasons. On the one hand, the government in Beijing has committed to ambitious climate goals and is working on the gradual decarbonization of its industry. On the other hand, electricity demand in the People's Republic continues to grow, which is likely to persist in the coming years, especially due to advancing digitalization and the introduction of artificial intelligence.

Furthermore, energy in China is always considered a matter of national security. The aim is to become independent from imports, viewing renewable energy and nuclear power as important elements of its self-sufficiency.

Henrik Bork, longtime China correspondent for the Süddeutsche Zeitung and the Frankfurter Rundschau, is Managing Director at Asia Waypoint, a consulting agency specializing in China and based in Beijing. "China Market Insider" is a joint project of the Vogel Communications Group, Würzburg, and Jigong Vogel Media Advertising in Beijing.