This is the first time a new hydraulic unit rotor has been installed at the station. The refurbishment of the station is part of the comprehensive "New Energy" modernisation programme at En+ Group’s Siberian hydropower plants.
The new hydraulic unit was delivered to the Irkutsk HPP in parts. The final assembly of the generator and rotor was carried out at the assembly site and in the power plant's turbine hall. The assembled generator rotor weighing 477 tons was moved into the generator’s stator bore with the help of two powerful turbine hall cranes, each with a lifting capacity of 275 tons.
The operation of transferring a generator rotor requires specialist skills. The rotor is almost 11 meters in diameter, therefore installation requires a high level of accuracy: crane operators move down the rotor into the bore of the generator stator, which is only 4 centimetres wider than the rotor. Once in, the mounting holes of the turbine and generator shafts have to be lined up, requiring accuracy to within a fraction of a millimetre.
The new generator rotor is structurally different from the old model: the height, the number of poles and the mass have all been reduced. Modern, more durable and efficient types of steel were used in its design, and this will improve the reliability and efficiency of the station equipment. The capacity of the entire hydraulic unit will also increase significantly: from 82.8 MW to 105.7 MW. The assembled unit meets all of the latest environmental requirements, as well as the operational reliability and safety requirements for hydropower equipment at HPPs.
The replacement of hydraulic unit No. 2 at the Irkutsk HPP is part of En+ Group’s comprehensive "New Energy" programme to modernise hydropower plants on the Angara and Yenisei cascade. The modernization of the HPPs’ equipment will increase their efficiency, reduce the cost of repair work, and improve the performance of the units and stations in general. The programme includes a comprehensive replacement of not only the main (hydraulic units, impellers) but also auxiliary equipment. The programme is designed to run until 2046. Investments up to 2026 including costs already incurred will amount to 21 billion rubles.
As a result of the programme, starting from 2022 the power output from En+ Group’s Siberian hydropower plants is expected to increase by 2 TWh, with the same water volumes passing through the turbines. This will reduce greenhouse gas emissions by 2.3 million tons per year, which will have a positive impact on the ecology of the Siberian regions.