Localized DC Dry Capacitors Break Technological Monopoly Enabling Independent Innovation

On May 30, China achieved another critical milestone in the localization of high-end power capacitors with the successful on-site acceptance test of domestically produced 2.8 KV 3 mF DC dry capacitors for STATCOM at the 500 KV Zongjiang Substation. This marks the second major breakthrough in core equipment within six months, following the March commissioning of 4 KV UHV-grade capacitors at the ±800 KV Liuzhou Converter Station. These advancements signal China’s progress toward a fully independent innovation chain—from material R&D to system integration—reducing reliance on imports.

From Zero to One: Breaking Foreign Monopolies

DC dry capacitors, a core component of flexible DC converters, were long dominated by foreign suppliers. To overcome this, Southern Power Grid partnered with Sinopec, Foshan Plastics Group, Huazhong University of Science and Technology, Sichuan University, and others to develop a groundbreaking "one-step" synthesis technology for ultra-clean polypropylene pellets. Using world-leading high-activity catalysts, this innovation slashes production steps, cuts washing pollution, and reduces energy consumption by 30%. It also represents the first global application of such technology in UHV projects.

Collaborative Innovation Drives Industrial Clusters

Since the first domestically produced flexible DC dry capacitor entered service in 2023, China’s high-end capacitor industry has rapidly expanded. Localized polypropylene films (5.5μm, 4.8μm, and 3μm) are now mass-produced, with participating enterprises growing from 10+ to 28, spanning industrial controls, renewable energy, and other strategic sectors. Southern Power Grid Research Institute has partnered with CRRC Ningbo Herong, Wuxi CRE, Lion Great Exploit, Nissei Electronics, and others, with annual DC dry capacitor deployments expected to exceed 100,000 units.

Ecosystem Leadership: From R&D to Standards

"This success exemplifies cross-industry chain collaboration," said Lu Yong, Deputy Director of Southern Power Grid Research Institute. As the industrial "chain leader," the company has driven intelligent upgrades and technological iteration across the sector, yielding 30+ core patents and 5 new standards. Next, the team will focus on high-temperature capacitor materials to further support China’s new power systems and carbon neutrality goals.

The 2.8 KV capacitor’s successful testing provides a replicable "Southern Power Grid model" for localizing critical technologies and paves the way for large-scale adoption.