Technicians reinstall repaired stator and rotor at Czech Dlouhé stráně power plant

In recent days, technicians reinstalled the repaired stator and rotor in generating unit TG1 at the Dlouhé stráně pumped-storage hydropower plant in the Šumperk region. This was one of the key milestones in this year’s modernisation of the plant. The stator weighs 280 tonnes and the rotor 410 tonnes. For each operation, technicians had to use two overhead cranes, each with a lifting capacity of 250 tonnes, and connect them with a special lifting beam. Vladislav Sobol, spokesperson for ČEZ Group, told the Czech News Agency today.

ČEZ invested more than 800 million crowns in repairs and investment at Dlouhé stráně this year and last year. Technicians had to work with millimetre precision when reinstalling the stator and rotor. “It was a real masterpiece,” said plant manager Ludvík Štrobl.

During the plant upgrade, experts also replaced the stator winding and realigned the entire generating unit. “The excitation system and the plant’s control system have also been modernised, and the hydraulic motor repaired. Further repairs and smaller investments across the plant site are now being completed,” Sobol said.

The repairs are part of the gradual renewal of key components of the turbine-generator sets, which have been in service for almost 30 years. “The main goal is to ensure the plant continues to operate reliably in the future. It is becoming increasingly important to the Czech energy sector: in addition to meeting morning and evening peaks in electricity demand, Dlouhé stráně is now used much more frequently as an energy storage facility, helping to maintain balance in the transmission system as electricity generation from renewable sources increases,” the spokesperson said.

The Dlouhé stráně pumped-storage hydropower plant began operating in 1996. Its machine hall and other technology are located deep underground.

In 2023, ČEZ invested 111 million crowns in improving the plant’s operational safety and reliability, compared with 60 million crowns in 2022. In 2021, energy sector workers raised the operating level of the upper reservoir by 70 centimetres, making it possible to store around six percent more electricity in a single generating cycle than before.