With the successful replacement of the No. 2 air tank on Unit 19, Gezhouba Hydropower Plant has officially concluded its comprehensive pressure vessel renewal and upgrading project. Spanning eight years and encompassing 110 vessels across the station, the initiative has not only eliminated potential safety hazards associated with aging equipment at their source, but also laid a solid hardware foundation for digital upgrades. This milestone marks another practical step by Gezhouba Hydropower Plant in implementing the national strategy for large-scale equipment renewal and enhancing the inherent safety of energy infrastructure.

Can Aging "Veteran" Equipment Relies Solely on Patchwork Repairs?

Pressure vessels are critical equipment for ensuring the oil and gas supply and buffer pressure regulation of hydropower units. A failure can trigger a chain reaction affecting the entire gas and oil system and unit protection devices, causing cascading safety risks and directly impacting the safe and stable operation of the station. The over one hundred pressure vessels at Gezhouba Hydropower Plant, much like "veterans" that have stood guard for over four decades, have long shouldered high-load operations, supporting the stable running of the units throughout their service life. As their service life approached the design lifespan, issues such as material fatigue of the vessels themselves gradually emerged, making potential safety hazards impossible to ignore. To hold the red line for work safety, in 2018, Gezhouba Hydropower Plant made the resolute decision to launch the largest-ever comprehensive renewal of its pressure vessels. By choosing complete renewal over repeated patching, the Plant sought to address the problem of equipment aging at its root.

How is the Renewal of One Hundred Pressure Vessels Tied to National Energy Security?

As the ballast and regulator of China's clean energy system, hydropower is seeing its strategic position become increasingly prominent in building a new-type power system. Especially now, with the large-scale integration of new energy sources and the pressing task of ensuring power supply, the ability of backbone hydropower stations to remain stable, regulate output, and ramp up at a moment's notice directly affects cross-regional power security and grid resilience. For Gezhouba Hydropower Plant—a backbone hydropower hub in the Yangtze River basin and a key node for ensuring clean energy supply—the inherent safety of its equipment is of paramount importance. Aligned with the new national energy security strategy and guided by the macro policy for large-scale equipment renewal, this renewal consolidates the hardware foundation of the country's strategic infrastructure by replacing obsolete equipment and enhancing operational efficiency. It safeguards national energy security and high-quality socioeconomic development with intrinsic equipment safety and concrete gains in quality.

How were Safety and Power Supply Assurance Balanced During the Eight-Year Coordinated Campaign?

To prevent concentrated construction from compressing maintenance windows and compromising power supply security, Gezhouba Hydropower Plant carefully designed a phased renewal plan starting with pilot projects. Between 2018 and 2019, a pilot upgrading was first completed for Unit 13, thoroughly testing and validating the process route, welding inspection standards, disassembly and assembly procedures, and safety measures, thereby establishing replicable construction procedures and maintenance standards. In the following years, by adopting an incremental, fast-paced approach instead of an all-out push, the Plant traded time for greater operational flexibility. This not only avoided systemic risks but also built up well-honed technical expertise for the large-scale upgrade of the entire station. For high-risk combined scenarios involving depressurization, air replenishment, and heavy lifting, the Plant enforced round-the-clock closed-loop inspections and cross-departmental coordination, using procedural certainty to lock down risk uncertainty and truly achieving both equipment upgrades and stable power supply without compromise.

Not Just "Replacement" But Also "Upgrading": Building a Digital Line of Defense for Compliance of Special Equipment!

This renewal was by no means a simple "new-for-old" swap; it was a quality-driven project that ensured compliance with special equipment standards while advancing digital upgrades. During the overhaul of the medium- and low-pressure air systems, complementary sensors were installed alongside the tank replacements. Online monitoring modules for key parameters such as pressure and oil level were upgraded, and a hardware system for real-time monitoring and control was established. This brought about a fundamental shift in the management of special equipment operations—from manual periodic inspections and post-fault handling to 24/7 real-time monitoring, early warning of anomalies, and precise data control—further consolidating the foundation for compliant special equipment operation and enhancing the station's digital O&M capabilities.

Eight years of dedication have paid off: 110 pressure vessels have been renewed and put back into service, achieving a qualitative leap in the safety and stability of the station's oil and gas systems. Going forward, Gezhouba Hydropower Plant will continue to intensify its efforts in fine management, standardized maintenance, and smart O&M, ensuring that this strategic national asset, which has weathered over forty years of challenges, continues to deliver clean energy to the nation's energy sector in a safe, stable, and efficient manner.