Somthing About Hydroelectric Power Plant (1)
Author: source: date: 2020-05-15 11:06:05
Hydropower plant is a hydroelectric power plant. It is a factory that converts the potential energy and kinetic energy of water into electrical energy. Its basic production process is: drawing water from a high place in a river or other reservoirs, using the pressure or velocity of the water to impulse the turbine to rotate, transforming gravitational potential energy and kinetic energy into mechanical energy, and then the turbine driving the generator to rotate, converting mechanical energy into electrical energy. The power station is generally composed of four major parts: water-retaining structures (dams), flood discharge structures (spillways or gates), water diversion structures (diversion channels or tunnels, including surge shafts), and power plant buildings (including tailraces and booster stations). composition. The main components are: hydraulic structures, hydraulic machinery equipment, power generation equipment, substation equipment, power distribution equipment, power transmission equipment and control and auxiliary equipment.
While the world economy continues to grow rapidly and industrial modernization is accelerating, resource and environmental constraints are tightening, energy supply is becoming tight, and ecological and environmental pressures continue to increase. Accordingly, accelerating the development of hydropower resources in the west and realizing the transmission of electricity from west to east are undoubtedly of great significance for solving the energy shortage problem in the development of the national economy, improving the ecological environment, and promoting the coordination and sustainable development of the regional economy. In addition, vigorously developing hydropower will help narrow the gap between urban and rural areas, improve rural production and living conditions, and play an irreplaceable role in promoting local agricultural production, increasing farmers' income, accelerating the pace of poverty alleviation, promoting national unity, and maintaining social stability. The development of hydropower through investment promotion, tax increase and related service industry development will transform local resource advantages into economic advantages and industrial advantages, thereby driving the development of other industries, forming a strong supporting industrial cluster, and effectively promoting the overall development of the local economy .
Principles of hydropower
Hydroelectric power is the use of hydraulic power (with a head) to drive hydraulic machinery (turbines) to turn, turning water energy into rotating mechanical energy. If another machinery (generator) is connected to the turbine, electricity can be generated as the turbine rotates. At this time, mechanical energy is transformed into electrical energy .
In a sense, hydropower is the conversion process of the potential energy of water into rotating mechanical energy, and then into electrical energy. According to the principle, the output formula of hydropower can be calculated as follows:
P = 9.81ηHQ
P: Output unit: kW (kw) The power transmitted from the unit side.
H: water head unit: m (meter) the effective water head acting on the turbine, it is equal to the difference between the reservoir water level and the downstream water level (ie: gross water head) minus the water head loss of the diversion part, the water head loss △ h, according to experience, generally Hg 3% to 10% of (Mao Shui Tau), the short value of the water channel is short.
Q: Flow unit: m3 / s (cubic meter / second) The reference flow of the hydropower plant's turbine.
Η: The efficiency of the hydro-generator set, including the efficiency of the hydro-turbine and the generator. Η is not only related to the type and parameters of the hydro-turbine and generator, but also changes randomly with the change of the operating conditions of the group. To simplify the calculation, let k = 9.81η, then the output formula can be simplified to:
P = kHQ
K: The output coefficient of the hydropower station. Large and medium-sized hydropower stations k = 8.0 ~ 8.5; small and medium-sized hydropower stations k = 6.5 ~ 8.0, for small power plants: k = 6.0 ~ 6.5.
Countries generally designate hydropower stations with an installed capacity of less than 5,000 kW as small hydropower stations, 5,000-100,000 kW as medium-sized hydropower stations, 100,000-1 million kW as large hydropower stations, and more than 1 million kW as giant hydropower stations.