Today, Kyrgyzstan is one of the three leading producers and exporters of electricity among the CIS countries, but this was not always the case. Until 1917, only 5 tiny coal and diesel stations operated on the territory of the country, which were enough only for street lighting, by 1940 several hydroelectric power plants appeared, but they were not enough. Everything changed in 1975, when the Toktogul HPP was commissioned.
Power plant location
To cover the needs of the republic in electricity, it was decided to build the Toktogul hydroelectric power station on the Naryn River in Kyrgyzstan, which began in 1962. The place for the construction of the station was a narrow gorge with a depth of 1,500 meters in the mountains of the Central Tien Shan at the exit of the Naryn River from the Ketmen-Tyube valley, with a slope of 65 - 70 °. The structures of the future power plant were developed taking into account the increased seismicity of the area.
Building Technology
The complexity of the conditions in which it was supposed to conductconstruction required non-standard engineering solutions. Here, for the first time, the technology of layer-by-layer laying of concrete over large areas was applied using special-design electric tractors. The method of craneless concreting, implemented at the construction of the Toktogul HPP dam, allowed to significantly reduce costs, reduce work time and increase labor productivity. This technique of building large-scale concrete structures became known as the Toktogul method.
Dam and Power Plant
The result of incredible efforts was a dam with a height of 215 and a length of 292.5 meters, consisting of a central and six coastal sections. The entire volume of concrete laid in the structure is 3.2 million cubic meters. Today, more than two thousand devices monitor the state of the dam. The impressive dimensions of the dam and the complexity of its design can be understood even from the photo of the Toktogul HPP.
The building of the power plant itself with four hydraulic units located in two rows adjoins the dam from the downstream side. The plant's radial-axial turbines drive hydrogenerators with a total capacity of 1,200,000 kW. Power is supplied by four step-up transformers connected to the generators, located in special chambers at the level of the machine room.
Toktogul waterworks
In addition to the dam and the power plant building, the Toktogul hydroelectric complex includes turbine water conduits, a reservoir, a switchgear, two deep and onesurface spillway.
Water to the turbines of the Toktogul HPP comes through four conduits located in the central segment of the dam and having a diameter of 7.5 meters. Emergency spillway is carried out using a surface drain with a capacity of 900 cubic meters per second, and deep spillways with a diameter of 30 meters, overlapped by special gates.
The open switchgear of the Toktogul hydroelectric complex is built according to a quadrangular scheme. Features of the terrain, increased danger of rockfalls, lack of flat ground and the width of the gorge caused this part of the hydroelectric complex to be located 3.5 kilometers from the power plant, in the valley of the Kara-Suu River.
Toktogul reservoir
Surrounded by majestic mountains, the reservoir of the Toktogul hydroelectric power station is located in the Ketmen-Tyube valley and is the largest in Central Asia. The dimensions of this water body are impressive - it has a length of 65 kilometers, and in some places the depth reaches 120 meters. The surface area of the reservoir is about 285 square kilometers, the volume of water is 195 billion cubic meters. Its filling began in 1973 and ended only by the time the power plant was launched.
Mysterious accident
The first wear and tear problems came to light in February 2008, when the plant's on-duty personnel stopped one of the units after noticing a high level of oil in the turbine bearing due to cracked tubes.oil coolers.
December 27, 2012 in Kyrgyzstan was declared a mode of limited energy consumption. The reason was an emergency situation at the Toktogul HPP. The accident occurred at hydroelectric unit No. 4. As experts later reported, it turned out that the labyrinth seal in the generator wheel was torn off, preventing water from entering under the turbine cover, due to which excess pressure formed there, which disabled the mechanisms. Despite the first statements about the insignificance of the incident, it was later said that the promptly identified problems made it possible to avoid a major accident similar to the one that happened at the Sayano-Shushenskaya HPP.
2015-2016 Incidents
The events of 2012 were not the only ones in a series of disasters at the Toktogul HPP. During the last week of December 2015, two emergencies occurred at the power plant. On December 23, the transformer of hydroelectric unit No. 2 broke down, and on December 28, due to the deterioration of cable lines, oil leaked from high-voltage cables. As a result, energy production was halved - to 600 MW. A year later, on December 15, 2016, an accident occurred again at the Toktogul HPP. Power engineers again let down hydroelectric unit No. 2 - its auxiliary equipment failed.
Regular technical problems at the power plant prompted the Kyrgyz government to decide to start reconstruction and modernization at the country's largest hydroelectric power station. It is expected that after the completion of the work, the capacity of the Toktogul HPP will increase by 240 MW, and the total durationservice life will increase by 35-40 years. The reconstruction is being carried out with the involvement of foreign specialists, the planned costs will exceed $400 million.
