water-power

What is the principle of hydroelectric power generation?

When the gravitational potential energy of water is converted into kinetic energy, the turbine starts to rotate. If we connect the generator with the turbine, the generator can start generating electricity. If we raise the water level to wash the turbine, we can find that the speed of the turbine increases. Therefore, as we all know, the greater the water level difference, the greater the kinetic energy obtained by the turbine and the higher the convertible electric energy. This is the basic principle of hydropower. The process of energy conversion is that the gravitational potential energy of upstream water is converted into kinetic energy of water flow. When water flows through the turbine, it transfers kinetic energy to the turbine, which drives the generator to rotate and converts kinetic energy into electrical energy. Therefore, it is a process of converting mechanical energy into electrical energy. Due to the different natural conditions of hydropower stations, the capacity and speed of hydro-generator sets vary widely. Usually, small hydro-generators and high-speed hydro-generators driven by impulse turbines mostly adopt horizontal structures. Large and medium-sized generators mostly adopt vertical structure. Because most hydropower stations are far away from cities, they usually need to supply power to loads through long transmission lines, so the power system puts forward higher requirements for the operation stability of hydro-generators: the motor parameters need to be carefully selected; There is a great demand for the moment of inertia of the rotor. Therefore, the appearance of hydro-generator is different from that of turbo-generator. Its rotor has a large diameter and a short length. The start-up and grid-connection time of hydro-generator is short, and the operation and scheduling are flexible. In addition to general power generation, it is especially suitable for peak shaving unit and emergency standby unit.

What is the principle of hydroelectric power generation?

The basic principle of hydropower generation is to use the water level difference to generate electricity with the hydro-generator, that is, to convert the potential energy of water into the mechanical energy of the hydro-generator, and then use the mechanical energy to drive the generator to obtain electricity. Taking advantage of this natural condition of water level difference, scientists effectively use fluid engineering and mechanical physics to achieve the highest power generation and let people use cheap and pollution-free electricity.

Advantages: Water energy is inexhaustible renewable and clean energy. However, in order to make effective use of natural water energy, it is necessary to artificially build hydraulic structures, such as dams, diversion pipes, culverts, etc., to concentrate the flow drop and adjust the flow. Therefore, the project investment is large and the construction period is long. However, hydropower has high efficiency, low power generation cost, fast start-up and easy adjustment. Because of the use of natural water flow, it is greatly influenced by natural conditions. Hydropower is often an important part of comprehensive utilization of water resources, which forms a comprehensive utilization system of water resources with shipping, aquaculture, irrigation, flood control and tourism.

Disadvantages:

1. Due to the terrain limitation, it is impossible to build too much capacity. The single machine capacity 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 swamps, it is vulnerable to feng shui disasters and affects other water conservancy undertakings. Power output is easily affected by weather, drought and rain.

It is not easy to increase the production capacity after the factory is completed.

5. Ecological destruction: the water erosion under the dam is intensified, the river changes and its influence on animals and plants.

6. Dams are needed, immigrants are needed, and investment in infrastructure construction is large.

7. Due to erosion, the fertile alluvial soil in the downstream is reduced.

What is the basic principle of hydropower generation?

The basic principle of power generation is to use the kinetic energy of running water to drive turbine blades to rotate.

Usually, a dam is built in the middle of the river to make use of this energy. A new invention is to supply power to portable equipment by using hydropower on a small scale.

Robert, an inventor from Ontario, Canada? Kamarika came up with the idea of installing a small hydraulic engine on the sole. He believes that these micro turbines can provide enough power for any portable equipment.

When the user walks, the conductive liquid in the heel liquid bag generates pressure, which urges the liquid to flow through the conduit and enter the hydropower generation module. The user continues to walk, the heel is lifted, and the liquid bag is subjected to downward pressure.

The flow of liquid drives the rotor and rotating shaft to rotate, generating electric energy.

What are the advantages and disadvantages of thermal power generation and hydropower generation?

The advantages of thermal power generation are easy site selection, less land occupation, less investment and short construction period.

The disadvantage is that the fuels used in thermal power plants, such as coal and oil, cannot be regenerated. It is a pity to burn them as fuel, and some pollution will also occur in production, which will lead to high power generation cost. The unit takes a long time to start, and it takes several hours to more than ten hours from cold start to grid-connected power generation.

The advantages of hydropower are renewable water resources and low production cost, which is only 1/5~ 1/3 of that of thermal power. There is no pollution, the unit starts quickly, and it only takes a few minutes for the unit to be connected to the grid for power generation.

Considering hydropower, shipping, irrigation and aquaculture comprehensively, building a water control project can improve its economic benefits. The disadvantage of hydropower is the difficulty in site selection. Dam construction requires high geological conditions. Building a reservoir will flood a large number of farmland and a large number of immigrants. Large reservoirs will destroy the ecological balance of local areas, with more investment and long construction period.

With regard to the investment and construction period of thermal power and hydropower, the research and practice in recent years have proved that the traditional theory that thermal power has less investment and shorter construction period than hydropower is one-sided. Thermal power generation needs a lot of coal and oil. In order to produce coal or oil, mines or oil fields should be built and railways or oil pipelines should be built to transport oil or coal.

If the investment in exploiting fuel and building railways or oil pipelines is included, the investment in hydropower is close to or even lower than that in thermal power. Therefore, giving priority to the development of hydropower is the correct policy.

Industrially developed countries give priority to the development of hydropower, and the utilization rate of hydropower resources is very high, reaching more than 90%, and hydropower accounts for a large proportion. Only by developing all hydropower resources can thermal power be developed. The exploitable hydraulic resources in China are as high as 3.

7.8 billion kilowatts, ranking first in the world. With the increasing shortage of energy and the growing voice of environmental protection, China has established the correct policy of giving priority to the development of hydropower, increased the investment and development of hydropower, and become the largest hydropower engineering market in the world.

According to statistics, at present, there are 58 large-scale hydropower stations built or under construction in China, among which there are 19 hydropower stations with installed capacity above 1000MW. By the end of 1997, China's total installed hydropower capacity was 60000MW, ranking third in the world after the United States and Canada.

At present, China's hydropower development rate is only 15%, far below the world average of 24%, and the hydropower development potential is still great.

Why can water generate electricity?

Their explanations are too professional. In fact, it is very simple, that is, power generation is the kinetic energy generated by water, and the electricity generated by turbines cannot be generated by static water itself. It can conduct electricity. Ha ha! Water is the most useful force in nature because it is the easiest to control. Tap water can be delivered through sluices or pipes. More importantly, a river can be divided into reservoirs, which can store a large amount of water and release the required amount when needed. Hydropower is usually planned as a hydropower station, usually based on a dam. The best geographical location is in a narrow valley with steep mountains. A dam built in such a valley can produce a reservoir with a length exceeding 100 km. Large-scale plans may be more than just a simple dam and reservoir. In the snow-capped mountains of Australia, water from the He Xue River is transported to 16 power plants through a series of underground tunnels. Water power is also used to store the surplus energy of other power plants, which can be handled by the so-called pumped storage power plant, using two independent reservoirs with different water levels. Under normal operation, the water in the higher reservoir is used to drive the turbine to generate electricity, while the water passing through the turbine is stored in the lower reservoir. Once there is surplus electricity, it is used to pump water from the lower reservoir back to the higher reservoir. Power demand peaks during the day, which also means that most power stations usually finish pumping water at night. Hydroelectric power generation is to use water with potential energy, such as rivers and lakes, to flow from high to low, and convert the potential energy contained in it into kinetic energy of the turbine, that is, to turn the turbine by using water flow and drop. Then the turbine is used as the prime Mover to drive the generator to generate electricity. Because the power voltage generated by hydropower plants is low, it is necessary to transmit it to remote users. After the transformer is boosted, it must be transported to substations in areas where users are concentrated through overhead transmission lines, and then reduced to a voltage suitable for household users and factory electrical equipment, and then transported to factories and household users through distribution lines. Use natural water flow as resources. Hydroelectric power generation is to use the dam to store water, choose day and night, inexhaustible, convenient and economical. Therefore, in the past 50 years, most countries in the world have focused on thermal power generation and tried to develop hydropower resources. At the beginning, more than 80% of power generation in the United States used firepower, and so far hydropower has accounted for nearly half, which shows the importance of developing hydropower. In countries lacking fuel, such as Switzerland and Italy, it is necessary to develop hydropower to make up for the shortage. According to its development function and operation mode, hydropower can be divided into conventional hydropower and pumped storage hydropower. There are 36 conventional hydropower stations in Taiwan Province Province with a total installed capacity of 6.5438+0.57 million kilowatts, which can be divided into three types according to their modes of transportation, such as reservoir-type power stations such as Deji, Shimen, Zengwen and Wushe. Adjustable power plants: such as Jianlong, Wu Li Power Plant and Chuanliu Power Plant. Due to the rapid increase of electricity consumption in Taiwan Province Province in recent years, in order to meet the needs of national economic construction, Taiwan Electric Power Company actively develops excellent hydraulic resources and provides sufficient power supply capacity. Therefore, according to the principle of water level difference, Tan Ming Pumped Storage Power Station Project was developed in Huariyuetan Scenic Area. Six 267 kW pumped storage hydro-generators are installed in Tan Ming Pumped Storage Hydropower Plant. The upper pool is Sun Moon Lake, and the lower pool is located in the downstream water chestnut valley. Pumped storage hydropower generation is carried out by using the drop of about 380 meters between the upper pool and the lower pool. In this way, the surplus power pumps the water from the lower pool to the upper pool for storage at night, and then releases the high-level water stored in the upper pool during the peak period of power consumption during the day. At first, the cost of building dams and transmission lines in hydropower plants driven by generators was higher than that in thermal power plants, but this difference has gradually approached in the last decade. Thirty years ago, the average construction cost of thermal power plants was $65,438+000 ~ $65,438+050 per kilowatt. So far, this figure has increased to $65,438+050 ~ 200 per kilowatt, and the construction cost of hydropower station is $65,438+080 ~ 250 per kilowatt. Although the construction cost is different, if the fuel cost and transportation cost are estimated, the total cost of hydropower generation is lower than that of thermal power plants, which is a great convenience. By the end of 1940, the hydropower stations built by countries around the world using their hydropower resources were about 70 million horsepower, but by the end of 1955, it had increased to 1.2 1 100 million horsepower. 15 years increased by more than 50 million horsepower, an increase of about 73%, which is really amazing. Hydroelectric power generation is to discharge water with high potential energy such as rivers and lakes to lower places, and use the kinetic energy of water to drive turbines, and then drive generator sets to generate electricity, which is supplied to users through power transmission and distribution systems. Therefore, the basic elements of hydropower generation are the flow and drop of rivers. With the change of power system, hydropower generation modes can be divided into the following four types: 1. It is used to block the flow of water in rivers and introduce it into power plants to generate electricity. Power generation depends on the natural flow of rivers, and it is generating electricity 24 hours a day. Early hydropower plants used this form to supply power to users all day, such as Wulai' Rough Pit' Gaoping' Zhumen' and other power plants. 2. Adjust the pool-type power plant, build small reservoirs in appropriate places of rivers, adjust the daily flow, and generate electricity for about 6 hours during peak hours. For example, power plants such as Wu Li of Stegosaurus. 3. Reservoir-type power plants build large reservoirs at appropriate locations of rivers to regulate and store the annual flow of rivers for daily power generation. Due to the limited river flow in the province, only peak power is provided most of the time. This location also has the function of flood storage and poverty alleviation. In addition to power generation, it has made great contributions to people's livelihood water supply and downstream irrigation.

Principle of hydroelectric power station

Hydroelectric power generation is to use water power (with water head) to drive hydraulic machinery (water turbine) to rotate and convert water energy into mechanical energy. If another machine (generator) is connected to the turbine, it can generate electricity with the rotation of the turbine, and then the mechanical energy is converted into electrical energy. In a sense, hydropower is a process in which the potential energy of water is converted into mechanical energy and then into electrical energy.

A comprehensive engineering facility that converts water energy into electric energy. Also known as hydroelectric power plant. It includes a series of hydropower station buildings and various hydropower station equipment built for producing electric energy by using water energy. The head is formed by collecting and adjusting the flow of natural water by using the drop of concentrated natural water flow in these buildings and transmitting it to the hydraulic turbine. Through the joint operation of hydraulic turbine and generator, the concentrated water energy is converted into electric energy, which is then input into the power grid through transformers, switching stations and transmission lines. In addition to the buildings needed for power generation, some hydropower stations often have other buildings that serve the purposes of comprehensive utilization such as flood control, irrigation, shipping, tree crossing and fish farming. The complex of these buildings is called hydropower station hub or water conservancy hub.

There are many classification methods for hydropower stations. According to the nature of water resources used by hydropower stations, they can be divided into three categories. ① Conventional hydropower station: using natural rivers, lakes and other water sources to generate electricity; (2) Pumped storage power station: when the power grid load is low, the surplus power is used to pump the water from the lower reservoir to the upper reservoir for storage, and when the power grid load is high, the water is released for power generation, and the tail water is discharged to the lower reservoir to meet the needs of power grid load such as peak shaving; (3) Tidal power station: use tidal energy formed by tidal fluctuation to generate electricity.

According to the utilization mode and regulation capacity of natural water flow, hydropower stations can be divided into two categories. (1) Radial-flow hydropower station: a hydropower station with no reservoir or small reservoir capacity and no or little regulation capacity for natural water; (2) Reservoir hydropower station: a hydropower station with a certain storage capacity and different regulation capabilities for natural water flow.

In the construction of hydropower stations, the following classification methods are often used. ① According to the development mode of hydropower stations, that is, according to the means of centralized head and the engineering layout of hydropower stations, it can be divided into three basic types: dam hydropower stations, diversion hydropower stations and dam-diversion hybrid hydropower stations. This is the most common classification method in engineering construction. ② According to the utilization head of hydropower station, it can be divided into high head, medium head and low head hydropower stations. There is no uniform regulation on the specific division of water head in the world. In some countries, hydropower stations with water heads below 15m are considered as low-head hydropower stations, 15~70m are medium-head hydropower stations, 7 1~250m are high-head hydropower stations, and those with water heads above 250m are ultra-high-head hydropower stations. China usually refers to high-head hydropower stations with a water head greater than 70m, low-head hydropower stations with a water head less than 30m and medium-head hydropower stations with a water head of 30~70m. This classification standard is applicable to the classification of main buildings of hydropower stations and the classification range of hydro-generator sets. ③ According to the installed capacity of hydropower stations, they can be divided into large, medium and small hydropower stations. Generally, hydropower stations with installed capacity less than 5000kW are classified as small hydropower stations, 500-654.38+ 10,000 kW are medium-sized hydropower stations, 654.38+10,000-654.38+10,000 kW are large hydropower stations, and those with installed capacity greater than 654.38+10,000 kW are giant hydropower stations. According to China's regulations, hydropower stations are divided into five levels, of which the installed capacity is above 750,000 kilowatts (large-scale (1) hydropower station), 750,000-250,000 kilowatts (large-scale (2) hydropower station), 250,000-25,000 kilowatts (medium-scale hydropower station) and 25,000-05 kilowatts (small-scale). But statistically, it is often considered as a small hydropower station below10.2 million kilowatts.

What are the advantages and disadvantages of hydropower?

water-power

Advantages:

(1) Use high water level to keep potential energy and convert it into kinetic energy to drive the prime mover.

(2) The potential energy of water quantity is converted into kinetic energy by using guide channel and penstock.

(3) The favorable hydraulic position is far away from the load center, far away from electricity, and the transmission cost is high.

(4) The efficiency of hydropower generation is over 90%.

(5) The cost per unit output power is the lowest.

(6) Power generation starts quickly and can be completed in a few minutes.

Disadvantages:

(1) Due to the terrain limitation, it is impossible to build a large capacity. The single machine capacity is about 300MW.

(2) The construction period is long and the construction cost is high.

(3) Being located in natural rivers or lakes and swamps, it is easily affected by geomantic disasters and affects other water conservancy undertakings. Power output is easily affected by weather, drought and rain.

(4) After the factory is completed, the production capacity is not easy to increase.