If you carefully examine the Yenisei River on the map, you can easily see the Yenisei cascade of hydroelectric power stations. A very important step is the Maine hydroelectric facility, located in Khakassia, in the vicinity of the village of Maina.
The tasks of the Main hydroelectric station
Maine Power Station fully covers the electricity needs of the Sayanogorsk Aluminum Plant. However, the main task of the station is to smooth out water level differences in the Yenisei, caused by changes in the operating modes of the Sayano-Shushenskaya hydroelectric station, located 22 kilometers upstream of the river.
The Maine Hydroelectric Power Station and its "elder sister" in the Yenisei cascade of hydroelectric power plants are united by a close technological relationship. Depending on the needs of the power grid, the Sayano-Shushenskaya hydroelectric power station daily increases or decreases its output by dumping different volumes of water.
The Mainskaya hydroelectric power station, being its counter-regulator, receives the flow into its reservoir, and then evenly passes excess water, protecting the underlying lands and settlements from flooding. This complex of hydraulic structures has no analogues in Russia.
The main stages of construction
The project of the Maine Hydroelectric Power Station was completed by the legendary Lenhydroproject, which in its 100 years of existence has developed 89 hydroelectric power stations. The builders of the hydroelectric power station were lucky to get by without the “tent romance” typical of large Soviet construction projects.
By the time construction began in 1979 in the village of Main, hydro-builders were waiting for finished residential buildings and socially significant objects. The village is located on the left bank of the Yenisei River. The map shows that today the village has grown and become part of the city of Sayanogorsk.
Already in 1980, the first cubic meters of concrete were laid in the structures of the Maine hydroelectric complex, and on November 24, 1984, builders completed the closure of the Yenisei site. The station gave the first current on December 31, 1984, when the 1st hydraulic unit was launched. The 2nd and 3rd units of the Main Hydroelectric Power Station were launched on September 28 and December 10, 1985, respectively. Construction was completed in 1987.
Key Specifications
The building of the Main hydroelectric station belongs to the riverbed type, that is, the flow of water passes directly through the station. In the turbine room there are 3 hydraulic units with a design capacity of 107 MW each. Rotary-vane turbines, designed for a pressure of 16.9 meters, set in motion the generators. The design average annual generation of the station is 1.72 billion kWh, and the total capacity is 321 MW.
After starting the power plant, it turned out that the turbines were designed incorrectly and could not work in the normal rotary-blade mode. The blades had to be fixed in a certain position, reducing the efficiency of the station.
The error did not allow the Mainskaya hydroelectric power station to develop its design capacity, and in 2006 one of the turbine wheels was replaced. This increased the plant’s efficiency, and the future plans of RusHydro, which owns the hydroelectric power station, included reconstruction and modernization of equipment.
Hydroelectric Power Station
The length of the pressure front of the facilities of the Main hydroelectric station is 750 meters. Waterworks comprise:
- The building of the power plant.
- A concrete spillway dam with 5 spillways 132.5 meters long and a maximum height of 31 meters.
- The left-bank bulk earth dam is 120 meters long and with a maximum height of 24 meters.
- Channel and right-bank loose earth dams with a total length of 502.5 meters and a maximum height of 30 meters. Along the crests of the dams is a road.
Pressure head hydraulic structures of the Main hydroelectric station form the Main reservoir. The filling of the reservoir bowl began in 1985. With a normal retaining level of 324 meters, the total volume of the reservoir is 116 million cubic meters, and the useful volume is 70.9 million cubic meters. The surface area of the reservoir is 11.5 square meters. kilometers, a length of 21.5 kilometers, a width of 500 and a maximum depth of 13 meters.
Reconstruction of the Main hydroelectric station
Mistakes in the development of turbines and long-term deterioration of hydroelectric power station equipment led to the beginning of a deep reconstruction of the Main Station, which should be completed by 2022. The modernization promises to increase the safety of hydraulic structures, reduce idle plant discharges by 20% and increase the capacity of generators by one and a half times.
As part of the modernization that began in 2011, all turbines, generators, power transformers, auxiliary pneumatic and oil systems, and water supply equipment will be replaced. In addition to updating equipment, it is planned to install modern seismometric instruments. There are also plans to build on the left bank of the Yenisei an additional coastal concrete spillway with 2 pressure tunnels.
To date, all hydraulic units have been replaced by generator switches, relay protection devices, a vibration control system has been installed, instead of an open switchgear, a modern gas-insulated control and distribution device for 220 kV has been installed.
The partially renewed Mainskaya Hydroelectric Power Station continues to honestly fulfill its duties, playing the role of a small but necessary assistant, without which the correct work of the energy giants of the Yenisei cascade is impossible.