Mainskaya HPP is a little helper of energy giants

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

If you carefully look at the Yenisei River on the map, you can easily notice the Yenisei cascade of hydroelectric power plants. A very important stage is the Mainsky hydroelectric complex, located in Khakassia, next to the village of Maina.

Tasks of the Mainskaya HPP

Mainskaya power plant fully covers the electricity needs of the Sayanogorsk aluminum smelter. However, the main task of the station is to smooth out water level fluctuations in the Yenisei, caused by a change in the operating modes of the Sayano-Shushenskaya HPP, located 22 kilometers upstream of the river.

The Main hydroelectric power station and its "big sister" in the Yenisei HPP cascade are united by a close technological relationship. Depending on the needs of the power grid, the Sayano-Shushenskaya HPP promptly increases or decreases its output every day, discharging different volumes of water.

The Mainskaya HPP, being its counter-regulator, receives the flow into its reservoir, and then evenly passes excess water, protecting the underlying land and settlements from flooding. This complex of hydraulic structures has no analogues in Russia.

Main stages of construction

The project of the Mainskaya hydroelectric power station was carried out by the legendary "Lenhydroproekt", which has developed 89 hydroelectric power plants over its 100 years of existence. The builders of the HPP were lucky to do without the "tent romance" typical of large construction projects in the USSR.

By the time construction work began in the village of Maina in 1979, ready-made residential buildings and socially significant facilities were waiting for hydro builders. The village is located on the left bank of the Yenisei River. The map shows that today the village has grown and became part of the city of Sayanogorsk.

Already in 1980, the first cubic meters of concrete were laid in the facilities of the Main hydroelectric complex, and on November 24, 1984, the builders completed the overlapping of the Yenisei alignment. The station gave its first current on December 31, 1984, when the 1st hydroelectric unit was launched. The 2nd and 3rd units of the Mainskaya HPP started operating on September 28 and December 10, 1985, respectively. Construction was completed in 1987.

Main Specifications

The building of the Mainskaya hydroelectric power station is of the channel type, that is, the flow of water passes directly through the station. There are 3 hydraulic units with a design capacity of 107 MW each in the engine room. The generators are set in motion by rotary-blade turbines, designed for a pressure of 16.9 meters. The design average annual output of the station is 1.72 billion kWh, the total capacity is 321 MW.

After the launch of the power plant, it turned out that the turbines were designed incorrectly and could not work normallyrotary-blade mode. The blades had to be fixed in a certain position, reducing the efficiency of the station.

A mistake did not allow the Mainskaya HPP to develop its design capacity, and in 2006 one of the turbine wheels was replaced. This increased the efficiency of the plant, and the future plans of RusHydro, which owns the HPP, included the reconstruction and modernization of equipment.

Hydroelectric Main power plant

The length of the pressure front of the structures of the Mainskaya HPP is 750 meters. The hydraulic unit is:

• Power plant building.
• Concrete weir with 5 spillways 132.5 meters long and 31 meters maximum height.
• Left bank earthfill dam 120 meters long and 24 meters maximum height.
• Channel and right-bank embankment earth dams with a total length of 502.5 meters and a maximum height of 30 meters. A motor road runs along the crests of the dams.

The pressurized hydraulic structures of the Mainskaya HPP form the Mainskoye Reservoir. The filling of the reservoir basin began in 1985. With a normal retaining level of 324 meters, the total volume of the reservoir is 116 million cubic meters, the useful volume is 70.9 million cubic meters. The surface area of the reservoir is 11.5 square meters. kilometers, length 21.5 kilometers, width 500 and maximum depth 13 meters.

Reconstruction of the Mainskaya HPP

Mistakes in the development of turbines and long-term wear and tear of hydroelectric equipment caused the start of a deepreconstruction of the Main station, which should be completed by 2022. The modernization promises to increase the safety of hydraulic structures, reduce idle discharges of the station by 20% and increase the power of generators by one and a half times.

As part of the modernization, which began in 2011, all turbines, generators, power transformers, auxiliary pneumatic and oil systems, technical 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 an additional onshore concrete spillway with 2 pressure tunnels on the left bank of the Yenisei.

To date, all hydroelectric units have been replaced with generator switches, relay protection devices, a vibration control system has been installed, and a modern 220 kV SF6 control and distribution device has been installed instead of an open switchgear.

The partially renovated Mainskaya HPP continues to honestly fulfill its duties, playing the role of a small but necessary assistant, without which the correct operation of the energy giants of the Yenisei cascade is impossible.