Miatlinskaya hydroelectric power station belongs to the Sulan cascade of hydroelectric power stations . The station is located on the Sulak River in Dagestan, near the village of Miatli. It performs three main functions - it generates electricity, is the regulator of the Chirkey hydropower plant (located upstream), supplies water from the reservoir to the city of Makhachkala (the capital of Dagestan). The station, in comparison with many objects of this type, is small in size, but unique in structure and complexity of construction. As part of the modernization program for the entire energy complex of Russia, the station is undergoing reconstruction.
Beginning of work
During the construction of the Chirkey hydroelectric station, it turned out that the amount of discharged water needed to be adjusted, so in 1973 it was decided to start the construction of another station. All work was carried out in difficult mountain conditions. The first project manager was D.A. Shandalov, who left the country shortly after the start of work, never having seen how the Miatlinskaya hydroelectric power station will be launched.
The history of the construction of the station was quite complicated. In 1976, a motorway was launched, which led to a shift in the slope and the emergence of a landslide on the right bank of the river, where several objects of the future station were already standing. Experts made an attempt to rectify the situation with the help of engineering structures, but the risk of a collapse remained.
Construction transfer
To ensure safety, the future facility was found a place two kilometers below the dam. These changes entailed the complexity of the entire system, it required the construction of an equalization tank shaft (25 meters in diameter, 76 meters in depth), a diversion water conduit (1700 meters), and a car tunnel (1,500 meters) on the left bank.
The overlapping of the Sulak river section took place in 1980, which redirected the flow of water along the dug derivational tunnel. To the honor of the builders is the fact of erecting the most complicated construction of an arch dam in just one season. At the same time, a new tiered technology of concrete work was mastered, the first pouring took place in 1983, and in the same period a tunnel failure occurred. Road traffic on the highway and the bridge was opened in 1984.
First starts
In 1985, installation of the first unit was started; at the end of the year, a planned flooding of the reservoir took place. The Myatlinskaya HPP launched the first hydraulic unit in December 1985, in January 1986 it gave industrial current, in the summer the second hydraulic unit was launched at the station, which became the start of the station’s full load.
The reservoir of the hydroelectric power station was filled to the planned mark of 154 kilometers in 1987. The equalization tank of the Myatlinskaya HPP has a length of about 15 kilometers with a width of 300 meters, a depth of up to 60 meters. The catchment at the mouth occupies a volume of 13.3 km. cubic meters, and in the range of about 14 m 3 , the total useful catchment capacity is from 16.2 to 32.7 km. cube The discharge flow rate of water through the facilities is 3000 m 3 / s at maximum load. During the construction of the tank, 151 hectares of agricultural land fell under flooding.
Miatlinskaya hydroelectric power station: overview
Description of station facilities:
- Arch dam. The design implemented at the station is one of unique and complex. Only three arched dams were built in the USSR - Meatl hydroelectric power station, Chirkei hydroelectric power station, Gunib hydroelectric power station. The height of the dam is 86.5 meters, a length of 179 meters.
- Building tunnel.
- The building of the hydroelectric station on the banks of the Sulak River.
- Equalization reservoir.
- Turbine conduits.
- Derivation tunnel coming from the dam.
The Myatlinskaya HPP is a relatively small station, its capacity is 220 MW, almost 700 million kW / h are generated per year. Two hydro turbines are installed at the hydroelectric power station, each of which has a capacity of 110 MW, with a water head of 46 meters per second. The design of the station was carried out by the Lengidroproekt Institute.
Turbine problems
The Myatlinskaya hydroelectric power station on the Sulak River has been under reconstruction since 2014. From the beginning of operation, it turned out that cracks quickly appeared on the blades of hydraulic turbines, which required constant repair. The installed hydraulic turbines did not differ in quality from the others working at other stations, but the conditions in which they were located were extreme, the water speed was 46 meters per second, which is why the blades quickly become unusable.
In addition, due to increased demand for electricity, the need arose to increase the output of electricity. As part of a comprehensive modernization program, RusHydro has entered into an agreement with the Austrian manufacturer Voith Hydro for the supply and replacement of impellers for both hydraulic units.
Reconstruction
In 2015, the reconstruction of the first hydraulic turbine was carried out, where, as planned, the impeller was replaced. It is equipped with seven blades having increased strength (2 tons more on each blade), the total weight of the wheel reaches 128 tons. To ensure uninterrupted operation, the oil pressure in the regulatory system was increased to 63 atmospheres (it was 40 atm.), This step allowed to reduce the amount of oil consumed and improve environmental performance. The measures taken have provided an increase in throughput, and in the long term, an increase in capacity is promised.
In addition to the turbine wheel, the control system, electrical protection of the generator and the cover of the turbine were replaced. Turbine capacity increased to 113 MW. The second hydraulic turbine was supposed to go through the same stage of reconstruction, but the work was postponed.
Scheduled work
The place where the Miatlinskaya Hydroelectric Power Station is located is a rocky area, and the Sulak River is often “naughty”, so conducting a routine inspection, repair and cleaning of the derivation canal is vital to ensure the operation of the hydroelectric power station. Preventive work is carried out once every thirty years, which happened in October 2016.
Since the launch of the station, the diversion tunnel has never been drained, its height is 12 meters and a width of about 15 meters, a length of 1.7 kilometers. To drain the water conduit, it was necessary to go down under the water and prepare the gates and the trash-holding systems for lifting, then close the sections and proceed to drain the water conduit. The gates are lifted using cranes, they are multi-ton structures, which can only be set in motion with the help of technology.
Inspection of the tunnel was carried out using laser scanning and in the traditional way - personal inspection. There were no global problems (cracks, voids), the thickness and monolithicity of concrete casting were not violated in any place. Minor repairs were still required. The filling of the water conduit took place as planned - the gate gates open only 15 centimeters, but this is enough for tons of water to flow into the system. Today Myatlinskaya HPP is operating normally.