Hydrotechnical facilities have been used since ancient times to generate energy. Today, a separate area of derivation stations is also developing successfully. These are structures characterized by a special drainage infrastructure that provides the ability to more effectively control flows even in difficult geographical conditions. At the basic level, the decoding of hydropower plants - a hydrological power station - is applicable to them.
The main components of derivational systems
The functional infrastructure of hydropower plants of this type is formed by water and energy facilities. The main part of the water part is made up of intakes, spillways and storage tanks. Between these waterworks, water is transported from the upper river cross section through artificial channels to reservoirs. As for energy facilities as part of derivational hydroelectric power stations, they are often represented by special water conduits that ensure the flow of flows to the receiving equipment in hydraulic structures.
Of key importance from the point of view of energy production is the equipping of such buildings with mechanisms that generate energy. In particular, it can be hydroturbines with transformers, as well as mechanical equipment that acts as the ultimate consumer of energy. In both cases, part of the generated electricity goes to the maintenance of the work of the common infrastructure, which includes control systems with automation, switchgears and systems for emergency shutdown.
Auxiliary components in derivational hydroelectric stations
This group of structural parts and structures of the station is designed to provide basic working conditions for functional waterworks. It can be sewer canals, trays, tunnels, administrative facilities, etc. The basis is technical facilities, due to which there is a drain from the river. In such a system, constructions for water reduction with jumpers and barrier control valves are provided. For example, in some derivational hydroelectric power stations there are fish protection and fish access facilities, thanks to which fish of certain sizes can go to spawning grounds, as well as in the opposite direction. For the period of construction of the station, temporary structures are also used that provide technical capabilities and conditions for the production of construction, installation and repair activities.
Station principle
Unlike the classical dam system, derivation involves the creation of a fully artificial channel with a diverted flow. A work unit in the form of a drainage branch throws part of the stream away from the river channel towards the lower reaches. Moreover, the lower target cannot always provide sufficient head power in natural conditions, therefore, additional pumps are often connected, as a rule, in closed systems. With regard to approaches to the mechanics of energy production, the principle of operation of the derivational hydroelectric station corresponds to the dam circuit. Bypassing the drainage channel, the flow is directed to hydrogenerators, where current is generated due to mechanical work. Again, mechanical energy can also be targeted at the final water delivery facility - this already depends on the purpose of the station.
Types of derivational hydroelectric power stations
There are the following signs of the classification of derivational hydropower plants:
- By power. Small power plants produce energy up to 30 MW, medium - up to 300 MW, and high-power - up to 1000 MW.
- By force of pressure. Low-pressure ones give out a pressure force of up to 30-50 m, medium ones - up to 100 m, and high-power - from 300 m.
- By design. Derivative hydropower plants of closed tunnel and open type are usually distinguished, but in practice, combined systems with partial inclusion of upper closing structures are often found.
- The height of the jumpers. An individual parameter that is set in the project document based on studies of the construction site of the hydroelectric power station. However, channel, coastal, and floodplain systems are fundamentally distinguished. The last two layouts are distinguished by the fact that they provide the highest jumpers designed to contain or allow flows in the event of an uncontrolled rise in water level.
Fields of application
Hydropower plants of this type can be used for various needs of industry and economy. The selection of the characteristics of the construction of a particular object is determined by local geographical and climatic conditions, as well as the requirements for the source of energy consumption. Where are derivational hydropower plants used in Russia? Traditionally, places with a large slope of the river flow are chosen, after which artificial conditions for derivation are created. The mountainous terrain, and in particular, the North Caucasus, is not considered the most favorable region for locating energy facilities in principle, but it is here that the main capacities are concentrated due to favorable conditions for creating a natural drainage with strong pressure. Also, in areas with difficult terrain, some of the structures included in the hydroelectric power station infrastructure are carried out underground. Such a solution provides not only structural, but also economic advantages. On the Kola Peninsula and in Karelia, open mid-mountain waterworks are used.
Conclusion
As a source of alternative energy, derivational hydropower plants have many advantages. These are environmentally friendly and powerful enough generators capable of reaching peak operating parameters in short periods of time. The problems of using such hydropower plants, in turn, are due to their structural complexity and high maintenance costs. In addition, the stringent requirements for the placement of derivational hydroelectric stations also create additional logistical difficulties in the transmission of electricity over long distances. Despite this, the schematic diagrams of such hydropower plants are still considered promising and in some sectors they are fully justified as an excellent model of a reliable source of cheap energy.