Miatlinskaya HPP: description, history and interesting facts

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

The Miatlinskaya HPP belongs to the Sulan cascade of HPPs. 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 counter-regulator of the Chirkeyskaya hydroelectric power station (located upstream of the river), 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 being reconstructed.

Getting Started

During the construction of the Chirkey hydroelectric power station, it became clear that the amount of discharged water needed to be adjusted, so in 1973 it was decided to start building another station. All work was carried out in difficult mountain conditions. The first project leader was the best arch dam specialist D. A. Shandalov, who left the country shortly after the start of work, without seeing how the Miatlinskaya HPP would be launched.

The history of the construction of the station was quite complex. In 1976, the excavation of the highway was started, which led to a slope shift and a landslide on the right bankrivers, where several objects of the future station already stood. Experts made an attempt to correct the situation with the help of engineering structures, but the risk of collapse remained.

Relocation of construction

To ensure the safety of the future object, they found a place two kilometers below the dam. These changes led to the complication of the entire system, it required the construction of a surge reservoir shaft (diameter 25 meters, depth - 76 meters), a diversion conduit (1700 meters), and an autotunnel (1500 meters) on the left bank.

Overlapping the alignment of the Sulak River occurred in 1980, which redirected the flow of water through a dug diversion tunnel. To the honor of the builders is the fact that the most complex structure of the arch dam was erected in just one season. At the same time, a new tiered technology of concrete work was mastered, the first pouring took place in 1983, in the same period the autotunnel was cut. The motorway and bridge were opened to vehicular traffic in 1984.

First launches

In 1985, the installation of the first unit was started, at the end of the year there was a planned flooding of the reservoir. The Miatlinskaya HPP launched the first hydroelectric unit in December 1985, in January 1986 it gave industrial current, in the summer the second hydroelectric unit was launched at the station, which was the start of the full load of the station.

The hydroelectric reservoir was filled to the planned mark of 154 kilometers in 1987. The surge tank of the Miatlinskaya HPP hasthe length is about 15 kilometers with a width of 300 meters, the depth reaches 60 meters. The catchment area at the mouth occupies a volume of 13.3 km. cubic meters, and in the alignment is about 14 m³, the total useful catchment capacity is from 16.2 to 32.7 km. cube The discharge water flow through the facilities is 3000 m^{3/s at maximum load. During the construction of the reservoir, 151 hectares of agricultural land fell under flooding.}

Miatlinskaya HPP: overview

Description of station facilities:

• Arch dam. The design implemented at the station is one of the unique and complex. Only three arch dams were built in the USSR - the Meatlinskaya HPP, the Chirkeyskaya HPP, and the Gunibskaya HPP. The dam is 86.5 meters high and 179 meters long.
• Construction tunnel.
• HPP building on the banks of the Sulak River.
• Equational reservoir.
• Turbine conduits.
• Diversion tunnel from the dam.

Miatlinskaya hydroelectric power station is a relatively small plant, its capacity is 220 MW, almost 700 million kWh is generated per year. The hydroelectric power plant has two hydro turbines, each with a capacity of 110 MW, with a water pressure of 46 meters per second. The station was designed by the Lengidroproekt Institute.

Problems of water turbines

The Miatlinskaya HPP on the Sulak River has been under reconstruction since 2014. From the beginning of operation, it turned out that on the blades of hydraulic turbines quickly appearcracks, which required constant repair. The installed hydro turbines did not differ in quality from the rest of those operating at other stations, but the conditions in which they were located were extreme, the speed of water movement was 46 meters per second, which caused the blades to quickly become unusable.

In addition, due to the increased demand for electricity, it became necessary to increase the production of electricity. As part of a comprehensive modernization program, RusHydro entered into an agreement with the Austrian manufacturer Voith Hydro for the supply and replacement of impellers for both hydroelectric 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 with 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 control system was increased to 63 atmospheres (it was 40 atm.), This step made it possible to reduce the amount of oil consumed and improve environmental performance. The measures taken have provided an increase in throughput, and in the future promises an increase in capacity.

In addition to the wheel of the hydroturbine, the control system, the electrical protection of the generator and the cover of the hydroturbine were replaced. Turbine power increased to 113 MW. The second hydro turbine was supposed to go through the same phase of reconstruction, but work has been delayed.

Planned work

The place where the Miatlinskaya hydroelectric power station is located belongs to a rocky area, and the Sulak River is often "naughty", so it is vital to carry out a scheduled inspection, repair and cleaning of the diversion canal 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 its width is about 15 meters, its length is 1.7 kilometers. To drain the conduit, it was necessary to go down under the water and prepare the gates and trash-retaining systems for lifting, then close the sections and start draining the conduit. Gates are lifted with cranes, they are multi-ton structures that can only be set in motion with the help of technology.

The inspection of the tunnel was carried out with the help of laser scanning and in the traditional way - by personal inspection. Global problems (cracks, voids) were not identified, the thickness and solidity of concrete casting were not violated in any place. Minor repairs were still needed. The filling of the conduit took place as planned - the shutter gates open only 15 centimeters, but this is enough for tons of water to begin to flow into the system. Today, the Miatlinskaya HPP is operating as normal.