RusHydro Informs on Ongoing Restoration Work Status at SS HPP
OREANDA-NEWS. Ongoing restoration work status at JSC RusHydro’s Sayano-Shushenskaya HPP as of August 26th, 2009 at 12:00, reported the press-centre of RusHydro.
Water passage regime and the condition of the spillway dam
Water inflow to the dam at the Sayano-Shushenskaya HPP is 2,950 cubic meters per second, and water is released through the spillway portion at a rate of 3,325 cubic meters per second. Nine of the spillway dam bays are open to the second degree and two of them are open to the first degree. The level of the upper pool and the release of water through the hydro-engineering structures at the HPP station fully comply with the water release regime recommended by the Angaro-Yenisei Basin Water Administration, appropriately adjusted in the operating mode.
The upper pool level is 537.57 meters (compared to a normal headwater level of 539 meters), and this level is dropping by 3 - 5 centimeters per day. Currently, the lower pool level is 324.62 meters.
Energy supply
The 500 kW outside switchgear has live voltage. Repair workers at the Sayano-Shushenskaya HPP are receiving power from the reserve transformer to supply and meet the switchgear-500's own needs. Cranes operating at the upper pool are being powered from an electrical power sub-station at the shore spillway construction site, with 0.4 kW being fed to the upper pool cranes in the usual manner.
Five 6/0.4 kW transformer sub-stations have been set up and connected in the area of the HPP's turbine room (three times 400 kWA and two times 630 kWA), as well as two 6/0.4 kW Package Transformer Sub-stations that have been set up at the end of the turbine room in the vicinity of hydro-turbine 10. A 35/6 kW transformer has been connected near the transformer area of block No. 5 and power has been supplied to busbars Sh-1 and Sh-3. Street lighting has been switched on at the site next to the station, as well as in the work zone in the turbine room.
A 10 MWA sub-station is being set up. The Н26 circuit-breaker panel for its own needs is being reviewed and the 6/0.4 KW T67 and T68 are being dried out. Work is currently under way to restore the Р6 and Р8 switch and control gears and the direct current board which feeds the H17 transformer sub-station. Work has also begun on restoring the Н2 and Н3 boards to satisfy its own needs. High voltage testing is being carried out on the Р10, Р8 and Р6 switch and control gears, as well as on the Н26 and Н30 boards and the Sh-2 busbar.
Power is now running to section 2 of the P-1 direct current board in the HPP's turbine room from the P-3 direct current board (using outside switchgear-500).
State of principal equipment
Based on the results of a visual examination, the accident completely destroyed hydro-turbines 2, 7 and 9. Turbines 1, 3, 4 and 10 have sustained damage to individual parts, while turbines 5 and 8 were somewhat damaged. Turbine 6 is in satisfactory condition.
Transformer groups 1T and 2T were damaged, but transformers 3T, 4T and 5T remain in satisfactory condition.
Current repair work
At present, work is under way to restore power equipment to a sufficient level to meet the HPP's own needs, and work is also continuing on clearing all dried out levels of the HPP's structure. Water is still constantly being pumped out of the power station's building.
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