Hydropower uses the mechanical energy of flowing water to produce electricity. The flowing water drives the turbine, causing the generator's magnetic windings to rotate, producing a changing magnetic field which then induces current in the surrounding coil windings, so that the generator emits electricity.
In order to obtain a greater flow of energy to push the turbine, the water flow acting on the turbine must have greater potential energy. The faster the water flow and the greater the head, the greater the potential energy of the water flow and the greater the kinetic energy obtained by converting the potential energy by the turbine.
People can use the difference in height of rivers or natural waterfalls to generate electricity. However, there are not many rivers or waterfalls with big drops on earth,and the river water is divided into flood period and dry water period, so it is impossible to achieve stable power generation.
Therefore, people use artificial methods to increase the fall and speed of water flow, that is, to build embankments in the narrowest sections of the river, to dam the river and store the water, so that the river water can flow out of the high embankment. It pours from above and drives the turbine to produce electricity. For example, the aforementioned Three Gorges, Gezhouba and Xiaolangdi are all large hydroelectric power stations. In addition, on small rivers in some mountainous areas, small hydroelectric power stations equipped with small turbines can be built to solve the problem of electricity consumption of dispersed populations. Compared to other methods of electricity production, hydropower hashas the characteristics of low cost, low pollution and low electricity price.
Manman Dam
(1) When hydropower is operating, water flows from upstream and impacts the turbine impeller, transferring the mechanical energy from the water to the wheel, then the turbine. The wheel drives the generator to produce electricity, converting the mechanical energy of the wheel into electrical energy. Therefore, mechanical energy is converted into electrical energy during the electricity generation process.
(2) When transmitting electric power over long distances, the loss of electric power on the transmission line mainly refers to the thermal effect of the current
According to Q=I2Rt, she. It can be seen that when the resistance remains unchanged. In the case of , the lower the current, the lower the power loss on the transmission line.
How to reduce the current? According to the forummule for calculating the electrical power P=UI, when the electrical power is constant, to reduce the current, the voltage must be increased.
The answer is therefore: mechanical (ultra) high pressure.