Water turbine is a kind of turbine machinery in fluid machinery. As early as about 100 BC, the prototype of water turbine – water turbine has been born. At that time, the main function was to drive machinery for grain processing and irrigation. Water turbine, as a mechanical device powered by water flow, has developed to the current water turbine, and its application scope has also been expanded. Then where are modern water turbines mainly used?
The water turbine is mainly used for pumped storage power station. When the load of the power system is lower than the basic load, it can be used as a water pump to use the excess power generation capacity to pump water from the downstream reservoir to the upstream reservoir and store energy in the form of potential energy; When the system load is higher than the base load, it can be used as a water turbine to generate electricity to adjust the peak load. Therefore, pure pumped storage power station can not increase the power of power system, but can improve the operation economy of thermal power generation units and improve the overall efficiency of power system. Since the 1950s, pumped storage units have been widely valued and developed rapidly all over the world.
The pumped storage units developed in the early stage or with high water head mostly adopt the three machine type, that is, they are composed of generator motor, water turbine and water pump in series. Its advantage is that the water turbine and water pump are designed separately, which can have high efficiency, and the rotation direction of the unit is the same when generating and pumping, which can be quickly converted from power generation to pumping, or from pumping to power generation. At the same time, the turbine can be used to start the unit. Its disadvantages are high cost and large investment in power station.
The blades of the inclined flow pump turbine runner can rotate and still have good operation performance when the water head and load change. However, limited by the hydraulic characteristics and material strength, its maximum water head was only 136.2m in the early 1980s (Kogen No. 1 power station in Japan). For higher water heads, Francis pump turbines are required.
The pumped storage power station is equipped with upper and lower reservoirs. Under the condition of storing the same energy, increasing the head can reduce the storage capacity, increase the unit speed and reduce the project cost. Therefore, high head energy storage power stations above 300 meters are developing rapidly. The Francis pump turbine with the highest water head in the world is installed in beinabashta power station in Yugoslavia. Its single unit power is 315 MW and the water head of the turbine is 600.3 meters; The pump has a head of 623.1m and a rotating speed of 428.6 R / min. it was put into operation in 1977. Since the 20th century, hydropower units have been developing towards high parameters and large capacity. With the increase of fire capacity in the power system and the development of nuclear power, in order to solve the problem of reasonable peak shaving, countries all over the world are actively building pumped storage power stations in addition to vigorously developing or expanding large-scale power stations in major water systems. Therefore, pump turbines have developed rapidly.
As a power machine that converts the energy of water flow into rotating mechanical energy, water turbine is an indispensable part in water turbine generator set. Nowadays, the problem of environmental protection is becoming more and more serious. Hydropower, a power generation method using clean energy, is increasing its application and promotion. In order to make full use of various hydraulic resources, tides, plain rivers with low drop and even waves have also attracted widespread attention, which has led to the rapid development of tubular turbines and other small units.
Post time: Apr-06-2022
