Since the onset of the Sanfu period (the hottest spell of the year), persistent high temperatures have gripped many regions across China, driving a continuous rise in power loads. As a key power source for the West-East Power Transmission Project and the South-North Power Transaction Project, the Three Gorges Hydropower Plant (“TGHPP”), with a total installed capacity of 22.5 GW, can generate 540 GWh of clean electricity per day under full-load operation. Faced with the prolonged heatwave, operation personnel of TGHPP have stood firm at their posts and fully delivered all O&M support tasks, including equipment monitoring, routine patrol inspections, peak regulation operations, inspection and maintenance.

Early in the morning, DONG Qi’ao, a duty operator with the Operation Department of TGHPP, put on his safety helmet, picked up an infrared thermometer, and started the first round of patrols of the day. The patrol route spanned primary and auxiliary equipment across the plant, covering the generator slip ring chamber, air duct, main transformers and the 500 kV GIS room, with three full patrol rounds carried out every day. “During high-temperature weather, we prioritize temperature monitoring of key unit components. Temperatures of the three bearing pads, stator bars and slip ring carbon brushes must all be closely tracked.” said DONG Qi’ao. Inside the slip ring chamber, DONG Qi’ao and his colleague CHI Jianing used infrared thermometers to take “temperature readings” of each piece of operating equipment one by one. During the major flood period, TGHPP staff intensified the frequency of equipment patrol inspections. Besides manual patrols, the plant’s Computer-based Supervisory Control System (CSCS) covered all equipment and facilities on site. Operation personnel conducted round-the-clock monitoring via CSCS. In the event of any abnormality, O&M personnel can spot it immediately via alarm signals and take corresponding measures. 

Meanwhile, ZHANG Canxin, shift director on duty, kept a close eye on the CSCS screens in the central control room of TGHPP, coordinating and directing the entire shift to carry out their tasks in an orderly manner. “Since July, extreme weather events including high temperatures, strong winds and thunderstorms have occurred frequently. Upon receiving meteorological warnings, we activate the emergency response in strict accordance with emergency plans.” said ZHANG Canxin. During gale and thunderstorm weather, attention is focused on transmission lines. The 500 kV outgoing lines, stretching dozens to hundreds of kilometers, may suffer temporary outages in the event of faults such as short circuits or lightning overvoltage. Operation personnel will conduct accident anticipation. “We have corresponding plans ready whether line reclosure succeeds or fails.” Under all circumstances, the top priority is to guarantee the safe operation of generating units.

Since the start of the flood season, frequent unit start-stop operations have been carried out for peak regulation. “In June, we recorded an average of more than 20 unit start-stop cycles per day, with a maximum of 35 cycles, representing heavy peak regulation tasks.” ZHANG Canxin stated. As the installed capacity of renewable energy continues to grow, TGHPP gives full play to its flexible peak regulation capability during the daytime peak of photovoltaic power output when power supply on the grid is sufficient. The plant proactively cuts generation load and stores water by retaining runoff, providing regulatory space for the accommodation of regional wind and solar power. When the evening power consumption peak arrives and photovoltaic output declines, it quickly raises unit output to fill the power shortfall. Frequent peak regulation imposes higher requirements on unit response performance. By delivering high-quality fundamental work including screen monitoring, patrol inspections, equipment operations and work ticket issuance, operation personnel monitor and maintain unit operating conditions in a timely fashion, to effectively secure reliable standby capacity and safe operation of the units.

Securing power supply amid high temperatures is no makeshift measure. JIANG Yu, Director of Operation Mode and Reliability, Production Management Department, TGHPP, explained: “Extreme weather events including heatwaves, torrential rains, gales and thunderstorms have struck frequently in summers of recent years. Rules governing equipment inspections and periodic rotation were established long ago. As external environmental conditions shift rapidly, equipment management needs to keep up. We re-identify equipment operation risks under special weather scenarios. In May 2025, we revised and issued the Detailed Rules for the Management of Equipment Inspection and Periodic Work of the Three Gorges Hydropower Plant, further specifying equipment inspection requirements, intervals and the division of responsibilities among departments.” The flood season constitutes the key front for enhanced equipment operation and maintenance. The Operation Department shall comprehensively step up inspections of primary equipment, including generator air ducts, outgoing transmission lines, DC equipment and flood discharge facilities, with all patrols conducted in strict compliance with regulations. Equipment rotation, tests, and other activities are carried out in strict accordance with periodic work regulations, ensuring that every task has a solid basis. In alignment with equipment management regulations, the Electrical Maintenance Department and the Mechanical & Hydraulic Maintenance Department have also conducted intensified inspections, as well as equipment diagnostics and operational analysis. During the flood season, this complete periodic equipment O&M system has effectively ensured the safe and stable long-term operation of the plant under heavy load.

From the infrared thermometers held by DONG Qi’ao and CHI Jianing to institutional documents, and from three rounds of on-site patrols each day to intensified special inspections amid the flood season — systems provide a lasting guarantee, while personnel stand fast on the front line. As the heatwave lingers on, CTG staff are channeling their sweat and perseverance into delivering a steady stream of clean electricity to households across the region, bringing much-needed relief to the public in the sweltering summer.