Efficiency of Hydroelectric Power 20, Efficiency of Hydroelectric Power

Flush a turbine with water with potential or kinetic energy, the turbine starts rotating, and if we connect the generator to the turbine, the generator starts generating electricity. If we raise the water level to flush the turbine, we can see that the turbine speed increases. Therefore, it can be seen that the greater the difference in water level, the greater the kinetic energy obtained by the turbine and the higher the convertible electrical energy.

This is the basic principle of hydroelectric power.

The energy conversion process is: the gravitational potential energy of the upstream water is converted into the kinetic energy of the water flow, and the kinetic energy is transferred to the steam turbine when the water flow passes through the water turbine, and the water turbine drives the generator to rotate to convert the kinetic energy into electrical energy. Hence the process by which mechanical energy is converted into electrical energy.

Due to the different natural conditions of hydropower stations, the capacity and speed of hydro-generator units vary widely. Generally, small hydro generators and high-speed hydro generators driven by impact turbines mostly adopt horizontal structures, while large and medium-sized speed generators mostly use vertical structures (see figure). Since most hydropower stations are located far away from the city and usually need to supply power to the load through a long transmission line, the power system puts forward higher requirements for the operational stability of the hydro generator

Motor parameters need to be carefully selected; The moment of inertia of the rotor is required to be large. Therefore, the appearance of the hydro generator is different from that of the steam turbine generator, with a large rotor diameter and a short length. In addition to general power generation, it is especially suitable for peak shaving unit and accident standby unit.

The maximum capacity of hydro-generator units has reached 700,000 kilowatts.

As for the principle of generators, high school physics is very clear, and their working principles are based on the laws of electromagnetic induction and electromagnetic force. Therefore, the general principle of its construction is to use appropriate magnetic and conductive materials to form magnetic circuits and circuits that carry out electromagnetic induction with each other, so as to generate electromagnetic power and achieve the purpose of energy conversion.

The efficiency of hydropower is less than 50%, while the transmission over long distances loses 10% to 30%.

It should be that the conversion from potential energy to kinetic energy is less lost and more friction is lost

Hello dear, it is a pleasure to solve the problem for you, the cost of power generation for hydropower? Answer: The main reason for hydropower generation is that the construction cost is high, the operating cost is relatively low, and the cost of medium-sized hydropower stations is about about yuan per kilowatt-hour, and the profit is about about about that.

On average, the unit cost of large-scale hydropower stations in China is about 7,000 yuan. In recent years, with the continuous increase in the cost of raw materials and other costs, the unit cost is more than 10,000 yuan kw, while the domestic unit of thermal power 30 600,000 kilowatts is 3,500-4,500 yuan kw, and the cost of ultra-supercritical million kw unit is 5,000 yuan kw, and the cost of hydropower is significantly higher than that of thermal power. In terms of construction cycle, the preparation period of the 300,000 kilowatt main unit of thermal power is half a year to one year, and the unit will be put into operation for power generation after three years; The construction period of large-scale hydropower is generally 2 years to intercept the flow, and the unit will be put into operation after 5 years.

However, the operating cost of hydropower is very low, and the long operation period and low operating cost of hydroelectric generating units are basically only labor and depreciation. At present, the operating cost of hydropower in China is generally yuan-yuan kilowatt-hours, which does not calculate such as environmental costs and resource costs, and the cost of thermal power is yuan-kilowatt-hours, and fluctuates up and down with the fluctuation of coal prices. The construction cost of nuclear power plants is 10,000 yuan per kilowatt at the 2005 price, which is calculated based on the localization rate of 70%, and is expected to be reached next year, and the operating cost is roughly equivalent to that of coal power.

In 2002, the total cost of nuclear power in France was 84,70 for coal power and 105,75 for natural gas. In 2001, the cost of nuclear power generation in the United States was 114 times that of coal power generation and 64 percent of that of natural gas power generation.

Summary. Advantage 1: High efficiency of hydroelectric power generation, low power generation cost, fast start of the unit, and easy adjustment. Due to the use of natural water flows, it is greatly affected by natural conditions.

Hydropower is often an important part of the comprehensive utilization of water resources, and forms a comprehensive utilization system of water resources with shipping, aquaculture, irrigation, flood control and tourism. 2. Hydropower is a renewable energy source with little impact on the environment. In addition to providing cheap electricity, it also has the following advantages:

Flood control, irrigation water and river navigation improvements are also needed to improve the region's transportation, electricity** and economy, especially tourism and aquaculture.

Advantage 1: High efficiency of hydroelectric power generation, low power generation cost, fast start of the unit, and easy adjustment. Due to the use of natural water flows, it is greatly affected by natural conditions. Hydropower is often an important part of the comprehensive utilization of water resources, and forms a comprehensive utilization system of water resources with shipping, aquaculture, irrigation, flood control and tourism.

2. Hydropower is a renewable energy source with little impact on the environment. In addition to providing cheap electricity, it has the following advantages: flood control, irrigation water, improved river navigation, and the project also improves transportation, electricity** and economy in the area, especially for tourism and aquaculture.

Disadvantage 1: Due to the limitation of the terrain, it is impossible to build too large capacity. The capacity of a single machine is about 300MW. 2. The construction period is long and the construction cost is high.

3. Because it is located in natural rivers or lakes and marshes, it is susceptible to feng shui disasters and affects other water conservancy undertakings. Electricity output is susceptible to weather, drought and rainfall. 4. It is not easy to increase the capacity after the factory is built.

5. Ecological damage: the erosion of water below the dam is intensified, the changes of rivers and the impact on animals and plants, etc.

It is generally combined heat and power.

Converted efficiency of heat supply. Sixty to seventy percent is combined heat and power.

Thermal power plant.

The production process can be summed up as the chemical energy of the fuel through high-temperature combustion.

It is converted into heat energy, which heats the fire into steam with a certain pressure and temperature, and then converts the heat energy into mechanical energy.

Through the electromagnetic induction of the generator, the mechanical energy is converted into electrical energy, and the steam turbine bypass system has become an important part of the thermal system of the intermediate reheat unit in the thermal system of the thermal power unit.

Generally 30, the world's best thermal power plants can convert about 40% of thermal energy into electrical energy; The thermal energy utilization rate of large heating power plants can only reach 60 70. In addition, thermal power generation burns a large amount of coal and fuel oil, causing environmental pollution, which has also become an increasingly concerned problem. An important issue in thermal power generation is to improve thermal efficiency by increasing the parameters of the boiler (pressure and temperature of steam).

Hydropower is actually a process of energy conversion.

1. Hydroelectric power generation uses rivers, lakes and other rivers and lakes with potential energy to flow to low places, converts the potential energy contained in them into the kinetic energy of the hydro turbine, and then uses the hydro turbine as the prime mover to drive the generator to generate electric energy.

2. Use the modified hydraulic power (with water head) to promote the rotation of hydraulic machinery (hydraulic turbine), convert water energy into mechanical energy, if another machinery (generator) is connected to the hydraulic turbine with the rotation of the hydraulic turbine, it can send electricity, and then the mechanical energy is converted into electrical energy.

3. Hydroelectric power is a conversion process in which the potential energy of water becomes mechanical energy and then becomes electrical energy.

Due to the low voltage of the voltage distributed by the hydroelectric power plant, in order to transmit to long-distance users, the voltage must be increased by the transformer, and then transmitted to the substation in the user concentration area by the overhead transmission circuit, and then reduced to the voltage suitable for household users and factory electrical equipment, and transmitted to the factories and household users by the distribution hall.

Hydroelectric power generation is a system that uses water with potential energy from rivers and lakes located at the top of the office to a low place, converts the potential energy contained in it into the kinetic energy of a hydraulic turbine, and then uses the hydroelectric turbine as the prime mover to drive the generator to generate electrical energy. If another machine (generator) is connected to the turbine to generate electricity when the turbine rotates, and then the mechanical energy is converted into electrical energy. In a sense, hydropower is the process of converting the potential energy of water into mechanical energy and then into electrical energy.

Due to the low voltage of the power generated by the hydroelectric power plant, in order to transmit to the long-distance users, the voltage must be increased by the transformer, and then transmitted to the substation in the user concentration area by the overhead transmission circuit, and then reduced to the voltage of the electrical equipment suitable for household users and factories, and transmitted to the factories and household users by the distribution line.

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Problem description: What are the pros and cons of hydroelectric power?

Analysis: Hydroelectric power.

Hydroelectric power generation uses rivers and lakes and other rivers and lakes that have potential energy at high places to flow to low places, converts the potential energy contained in them into the kinetic energy of the water turbine, and then uses the turbine as the prime mover to drive the generator to generate electricity. Use water power (with a water head) to drive the hydraulic machinery (water turbine) to rotate, the water energy is converted into mechanical energy, if another machine (generator) is connected to the water turbine to rotate with the water turbine can send out electricity, then the mechanical energy is converted into electrical energy. In a sense, hydroelectric power is the transformation of the potential energy of water into mechanical energy and then into electrical energy"Change the process.

Due to the low voltage of the electricity generated by the hydroelectric power plant, in order to transmit it to long-distance users, the voltage must be increased by the transformer, and then transmitted to the substation in the user concentration area by the overhead transmission circuit, and then reduced to the voltage of the electrical equipment suitable for household users and factories, and transmitted to the factories and household users by the distribution line.

Pros: clean energy, long-term benefits from a single investment, large energy reserves, inexhaustible, inexhaustible. Divert water to alleviate floods and droughts. The water level rises after impoundment, which is conducive to shipping. Vital energy sources**.

Disadvantages: Blocking fish return routes and hindering spawning (e.g. Chinese sturgeon). Rising water levels damage the upstream landscape, inundate some towns and dampen the ecological environment.

Rising water levels change local crustal pressures and may trigger geological disasters. Passing through the Shuixiang Dam requires locks, troublesome. Dams are strategic facilities that are targeted in wartime.

Dam collapse can seriously affect downstream safety.