The First Converter Transformer for the Chongqing-Guizhou Back-to-Back Interconnection Project Arrives at the Site

On October 30, a key project under China's 14th Five-Year Plan for Power Development—the Chongqing-Guizhou back-to-back interconnection project—reached a key milestone: the first converter transformer successfully arrived at the construction site of the Chongqing-Guizhou converter station in Longsheng Town, Qijiang District.

As the core equipment of the Chongqing-Guizhou converter station, the converter transformer plays a key role in enabling bidirectional power conversion and interconnection between the power grids of Chongqing and Guizhou. Its primary task is to reduce the voltage of the AC grid to the optimal operating voltage level required by the converter valve, ensuring that electricity can be transmitted precisely and efficiently.

This converter transformer set out from Changzhou, Jiangsu, on September 18. It first traveled along the Beijing-Hangzhou Grand Canal and the Yangtze River waterway to Changshou, then was transferred to rail transport to reach Wansheng, and finally was transported by specialized heavy-haul vehicles into the Chongqing-Guizhou converter station. The entire journey involved four transfer operations, lasted 42 days, and covered nearly 2,193 kilometers.

The converter transformer arrives at the Longsheng toll station in Qijiang District

Photo by Li Keyi

The first converter transformer to arrive is 10.564 meters long, 4.01 meters wide, and 4.83 meters high, weighing 344 tonnes. Throughout the transfer process, the construction team, taking into account fluctuations in waterway levels, railway scheduling and coordination, complex road conditions, and the four critical transfer operations, developed specialized support plans in advance. Dedicated personnel monitored the entire process, with controls implemented at each stage and seamless coordination between operations, ensuring strict risk control throughout every transportation and transfer procedure.

The converter transformer is transported along the Yangtze River

Photo by Li Keyi

It is understood that the Chongqing-Guizhou back-to-back interconnection project will have a total of 13 converter transformers at the station, and the last one is expected to arrive at the site in January 2027. After the project is completed, it will effectively establish an interconnection channel between State Grid and China Southern Power Grid, enable bidirectional peak shaving and mutual power supply between Chongqing and Guizhou, facilitate the efficient integration of clean energy from Southwest China, and strengthen regional power supply security.