Unipro PJSC Berezovskaya GRES Branch has completed scheduled repairs of Power Unit No. 1. The power unit has successfully passed in-process tests during a twelve-hour connection to the unified energy system of Siberia. These activities qualify as medium repairs of the power unit.
The power unit technical refurbishment program included a non-standard activity – repair of the boiler involving partial replacement of the convection reheater (CRH). Over the course of a 4-month campaign, the Branch dismantled and replaced 198 tons of equipment.
The project proved quite challenging due to the fact that installation of the boiler provided for the installation of all convective heating surfaces as part of a single subassembly, while the CRH is located in the middle of this subassembly, and therefore, it is impossible to replace the CRH using prefabricated subassemblies.
The old CRH packages have been dismantled and the new CRH packages have been installed using a monorail system inside the convective shaft. Over the course of these works, the power engineers developed and implemented a number of optimization initiatives, which made it possible to replace the equipment 15 days before the scheduled completion date.
The quality of the welds on the new reheater has been controlled by hydraulic testing with a test pressure of 49.5 kgf/cm2, and the quality of the welds on the convective shaft suspension pipes – with a test pressure of 392.5 kgf/cm2. All 4682 welded butt joints passed the tests with no remarks whatsoever. Currently, both operating power units of Unipro PJSC Berezovskaya GRES Branch have been successfully repaired as part of the scheduled maintenance campaign and are ready for reliable operation under maximum load during the winter season.