Derivative HPPs: description, principle of operation, where they are used

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

Hydrotechnical structures have been used since ancient times to generate energy. Nowadays, a separate direction of derivation stations is also successfully developing. These are structures characterized by a special drainage infrastructure that allows for more effective flow control even in difficult geographical conditions. At the basic level, the decoding of the hydroelectric power station is applicable to them - a hydrological power plant.

Main components of derivational systems

The functional infrastructure of HPPs of this type is formed by water and power facilities. The basis of the water-pressure part is made up of intakes, spillways and storage tanks. Between these waterworks, water is transferred from the upper range of the rivers through artificial channels to reservoirs. As for energy facilities as part of diversion HPPs, they are more often represented byspecial conduits that ensure the flow of flows to the receiving equipment in hydraulic buildings.

Equipment of such buildings with mechanisms that generate energy is of key importance in terms of energy production. In particular, these can be hydraulic turbines with transformers, as well as mechanical equipment that acts as the final consumer of energy. In both cases, part of the generated electricity is sent to service the operation of the common infrastructure, which includes control systems with automation, switchgear and emergency shutdown systems.

Auxiliary components in diversion hydropower plants

This group of structural parts and structures of the station is designed to provide basic conditions for the operation of functional hydroelectric facilities. These can be sewer channels, trays, tunnels, administrative facilities, etc. The basis is made up of technical structures, due to which the drainage from the river occurs. In such a system, structures for dewatering with jumpers and barrier control valves are provided. For example, in some diversion HPPs there are fish protection and fish passage structures, thanks to which fish of a certain size can pass to spawning grounds, as well as in the opposite direction. During the construction period of the station, temporary structures are also used to provide technical capabilities and conditions for the construction, installation and repair activities.

Station operation principle

Unlike the classic dam system, diversion involves the creation of a completely artificial channel with diverted flow. The working unit in the form of a drainage branch transfers part of the stream away from the riverbed towards the downstream. Moreover, the downstream section is not always able to 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 power generation, the principle of operation of a diversion hydroelectric power station corresponds to a dam scheme. Bypassing the drainage channel, the flow is directed to hydroelectric generators, where, due to mechanical work, current is generated. Again, mechanical energy can be targeted at the final object of water delivery - this already depends on the purpose of the station.

Types of diversion HPPs

There are the following signs of the classification of diversion hydropower plants:

• By power. Low power plants generate 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 head force of up to 30-50 m, medium ones - up to 100 m, and high-power ones - from 300 m.
• By design. Usually, diversion HPPs of closed tunnel and open type are distinguished, but in practice there are often combined systems with partial inclusion of upper closing structures.
• Height of jumpers. An individual parameter that is set in the projectdocument based on studies of the HPP construction site. However, channel, coastal and floodplain systems are fundamentally distinguished. The last two layouts differ in that they provide the highest cofferdams, designed to contain or pass flows in the event of an uncontrolled rise in water levels.

Application areas

Hydropower plants of this type can be used for various needs of industry and economy. The selection of characteristics for the construction of a particular facility is determined by local geographical and climatic conditions, as well as requirements for the source of energy consumption. Where are diversion HPPs used in Russia? Traditionally, places with a large slope of the river flow are chosen, after which artificial conditions for derivation are created. Mountainous terrain and, in particular, the North Caucasus, is considered not the most favorable region for the placement of energy facilities in principle, but it is here that the main capacities are concentrated due to favorable conditions for creating a natural drainage system with strong pressure. Also, in areas with difficult terrain, part of the structures included in the infrastructure of the hydroelectric power station are carried out underground. This solution provides not only structural, but also economic advantages. On the Kola Peninsula and in Karelia, open mid-mountain hydroelectric facilities are used.

Conclusion

As a source of alternative energy, diversion hydropower plants have many advantages. These are environmentally friendly and sufficiently powerful generators capable ofperiods of time to reach peak performance. The problems of using such HPPs, in turn, are due to their structural complexity and high maintenance costs. In addition, stringent requirements for the location of diversion hydropower plants also create additional logistical difficulties in the transmission of electricity over long distances. Despite this, the schematic diagrams of such hydroelectric power plants are still considered promising and in some industries fully justify themselves as an excellent model for a reliable source of cheap energy.