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I. Economic development and power demand
The development of the national economy and the improvement of people's lives are inseparable from electrical energy. Electrical energy can be easily converted into mechanical energy, thermal energy, magnetic energy, light energy, chemical energy, etc. It is expected that electricity will remain the most modern in the 21st century (at least 2050 years ago). The driving force is an important material basis for modern technology, people's lives and the development of new industries. The level of economic development of a country or region is compatible with its degree of electrification. In 1949, the total installed capacity of power generation equipment in mainland China was only 1.85 GW (1 GW = 1000 MW = 1 million kW), and the annual power generation was 4.3 TWh = 1 billion kWh = 1 billion kWh, ranking 21st and 25th respectively in the world. By the end of 1999, the total installed capacity of power generation equipment in China reached 298.8GW, and the annual power generation reached 1233.1TWh, ranking second in the world. However, by the end of 1999, China's per capita power generation capacity was only 0.24kW, ranking 80th in the world. The per capita electricity consumption is 979kWh, which is less than half of the world average. There are still 28 million people who do not have access to electricity. The contradiction between power supply and demand has not been fundamentally resolved.
Since the second half of 1996, the growth rate of power generation in the country has slowed down. In 1998, the power generation increased by only 2%. In some areas, the electricity supply is too high. This is related to China's electricity structure and industrial adjustment. In 1994, China's industrial electricity consumption accounted for 76.68% of the total electricity consumption, and the per capita electricity consumption of residents in the year was only 73kWh, which is far lower than the level required by our development stage. In the United States, electricity consumption in the 1960s accounted for 25.3% of the electricity used in society, and in 1986, electricity consumption in India accounted for 19%. The per capita power generation equipment in developed countries is 2 to 3 kW, and the per capita annual electricity consumption is 9 to 20 MWh. The current per capita power generation equipment and power generation in mainland China are more than 10 times different, and the difference between Hong Kong and Taiwan is more than 5 times. In 1998, Hong Kong's total installed capacity of power generation equipment was 11.255GW, with an annual power generation of 36.39TWh and a population of more than 600 million. In 1998, Taiwan's total installed capacity reached 32.634GW, with a power generation of 142.96TWh and a population of about 22 million.
Per capita installed capacity represents the level of power development in a country or region, and is generally proportional to its level of economic development and people's living standards. The higher the per capita electricity consumption, the higher the gross national product (GNP) and the higher the degree of economic development.
According to the planning and forecast of the power sector and experts, by 2050, the installed capacity of power generation equipment in China is 2TW, the population of the mainland is 1.53 billion, the annual electricity consumption per capita is about 6200kWh, and the per capita electricity consumption is about 1240kWh. It is equivalent to the per capita electricity consumption in West Germany, the former Soviet Union, France, the United Kingdom, and Hong Kong and Taiwan in the late 1990s. That is, in the first 50 years of the 21st century, we need to manufacture nearly 1.5 to 2.0 TW of power generation equipment to reach the level of moderately developed countries or regions in the world.
So far, power generation equipment and power generation in the world are mainly composed of thermal power generation (including coal, fuel, natural gas), nuclear power and hydropower. In recent years, power generation equipment using wind energy, solar energy and other energy sources has been actively carried out. The development of electric power on the basis of energy supply, China's water resources rank first in the world, and can be used for power generation between 300 and 378 GW. China's thermal power generation will mainly rely on coal and natural gas supply in the future. In addition to developing and developing natural gas, developing nuclear power and developing other energy sources such as wind, solar and geothermal, it also needs to save energy and reduce environmental pollution. In order to meet the application of electricity and electricity required for the development of China's national economy and the improvement of people's lives in the 21st century, it is necessary to develop high-efficiency power generation equipment and electrical equipment from the perspective of motor manufacturing, and to develop power generation equipment needed for new energy. Develop new materials, new structures, and new processes to create new varieties of motors.
At present, in China's energy consumption, electricity accounts for about 32%, coal energy consumption dominates, environmental pollution is serious, and the area of ​​acid rain has reached 1/3 of the country's land area. From 1990 to 1995, the national SO2 emissions increased from 15.71Gt to At 23.7 Gt, the economic loss caused by SO2 emissions alone accounts for 1.98% of GNP. Developed countries have used about 80% of coal for power generation, compared with less than 33% in China. Therefore, it is necessary to increase the proportion of electricity in energy consumption, and convert coal consumed in various industries, domestic boilers and civilians into electrical energy as much as possible to improve energy efficiency and protect the environment.
China's coal resources have accumulated proven reserves of more than 1,000 Tt, of which the recoverable amount is above 100Tt, which objectively forms a pattern of coal-based fuels in China's thermal power generation in the future.
There is no direct relationship between the design, manufacture and power generation of steam turbine generators and the clean combustion of coal. However, the large size of thermal power plants and nuclear power plants cannot be randomized due to the inherent characteristics of turbine generator design. The increase in capacity will increase accordingly, and the design and safety margins brought about by this need to be carefully analyzed. Turbine generators used in combined steam turbines also have fatigue life problems due to frequent starting. In any case, no matter what kind of thermal power or nuclear power, the last is the conversion of mechanical energy into electrical energy by steam turbine generators for the power grid and humans. Up to now, 75%-80% of the electricity in China and the world is Provided by a steam turbine generator. According to the analysis of the power sector and experts, by 2050, at least about 70% of China's electric energy is still provided by thermal power or nuclear power, that is, finally provided by steam turbine generators. Therefore, in the 21st century, the design of steam turbine generators, Manufacturing and operation technology should still receive corresponding attention.
In the 1990s, China's construction of power stations has been dominated by 200MW and 300MW units. At the beginning of the 21st century, thermal power construction should be gradually transitioned to 600MW units, mainly domestically. In addition to further optimizing 300MW, 600MW thermal power units and developing turbine generators required for combined cycle to reduce coal consumption, reduce pollution and increase availability, the important development direction of China's 21st century steam turbine generator manufacturing technology is to keep up. The development of the national economy and people's lives have increased the need for electricity, keeping pace with the large-capacity of nuclear power and thermal power, and gradually achieving "design autonomy" and "design localization."
Second, improve the availability and localization rate of 300MW and 600MW generators and manufacture a steam-steam combined cycle generator set
(1) Improve the availability and manufacturing quality of domestic 300MW and 600MW steam turbine generator sets, making it an internationally advanced and competitive product.
China will develop supercritical units to reduce coal consumption. As long as the size of the connection between the low-pressure cylinder and the generator of the steam turbine is constant, the turbine generators do not need to be modified with subcritical or supercritical, as long as they are accounted for with the supercritical gas turbine shaft system.
China's existing 300MW, 600MW water-hydrogen cooled steam turbine generator; 300MW dual-water internal cooling turbo generator has high efficiency, weight, parameters, annual operating hours, etc. have reached the international advanced level. In recent years, the state has stipulated that sub-critical 600MW and below capacity units that can be produced in China are generally not imported. This is crucial for the development of China's power station construction manufacturing industry and has a great impact on the development of China's national economy. The power station manufacturing industry is one of the important basic industries of the country. Most of the large nuclear power plants and thermal power plants in France, Germany, Japan, Russia, and the United States are manufactured in China. China plans to launch 70GW of large and medium-sized generators in the Ninth Five-Year Plan. Among them, 31.354 GW of imported equipment has been set up, and 70 GW of large and medium-sized generator sets of the "10th Five-Year Plan" have been put into operation at the end of the "Ninth Five-Year Plan" period, of which 31.354 GW has been set for import and export, and the end of the "Nine-Five" period is the first two years of "Five-Year" Preparing foreign capital to build a power station will also import 14.2GW. The import of these equipments has the reasons for utilizing foreign capital, opportunities for people to go abroad, high wages for imported unit power plants, and the fact that some technologies are not yet in the country, and the power sector does not trust the quality of domestically produced units.
Imported power station equipment will seriously affect the task of domestic manufacturing power plant equipment factories. At present, domestic power supply exceeds demand, and the power station manufacturing industry is facing a serious situation of less production tasks (thermal power, nuclear power), while the power station manufacturing industry, including its supporting raw materials, the downturn of the supporting parts production plant, will affect China's power supply further low. The excess of the level, the bad cycle of this industrial system will affect the sustainable development of the national economy, should cause serious attention to analysis, and take measures to prevent it. The loss of technical power in the power station manufacturing industry and the possible sluggishness or abandonment of equipment have attracted the attention of some leaders.
However, in terms of power plant equipment manufacturing units, it is necessary to improve product quality and reassure the power sector. Although it can be seen from the statistics of the Power Reliability Management Center in May 1999, the equivalent availability coefficient of China's 100MW and above thermal power coal-fired units increased from 88.19% in 1997 to 88.33% in 1998, but the product quality is still poor. The main reason for the equivalent unplanned outage of the generator set is that the 300MW generating unit is the most in operation in China. In 1998, the equivalent unplanned outage caused by the poor quality of the domestic thermal power unit accounted for 57.42 of the total equivalent unplanned outage hour. %. In addition, quality problems, major manufacturing and light quality problems still occur from time to time, mainly because raw materials and purchased parts are not strictly controlled, the design is unreasonable, the implementation process is not strict, the quality inspection is not strict, and the technology diffusion factory and the external The quality supervision of the factory is out of control.
1. The main materials and parts used in generators need to reach international level and localization
China's national economy continues to develop, power station equipment must be localized, and the main materials and components of steam turbine generators should also be made of high quality. In the past 20 years, the relevant units have done a lot of work in this area, and have achieved certain results, but there are still some gaps with the use requirements. For example, stator solid conductors and insulated hollow conductors used in generators are anaerobic in foreign countries. Copper, which is made by extrusion of hollow conductors. Oxygen-free copper has good welding performance and high electrical conductivity (2% to 4% higher than electrolytic copper). China has made hollow conductors. In recent years, the blanks have been used to make blanks and have been drawn several times. The above-mentioned production of oxygen-free copper rods may have intermittent points. It cannot be eliminated in the process of drawing. If the eddy current flaw detection is not detected, it becomes a hidden danger of hollow conductors. The Westinghouse purchase regulations require hollow conductors. Made by extrusion. Foreign large copper products factories all have vacuum smelting, continuous casting and extrusion equipment. Therefore, some products still use imported insulated hollow conductors. It is necessary to formulate plans and implement measures to make domestically-made wires and insulated hollow conductors reach the world advanced level. . At present, the solid wires of generators in China are still made of electrolytic copper, and no oxygen-free copper is used. Similarly, the electrical, mechanical strength and creep resistance of insulating materials used in steam turbine generators are also different from those of foreign products. The performance of rotor forgings has basically reached the foreign level, but in the forging manufacturing process, the yield is poor. Therefore, there are still quite a few imports, which causes cost increase and spare parts difficulties.
2. Strict process and quality inspection to improve product cleanliness
Summarize the experience and lessons of the quality problems that have occurred in China's domestic and foreign 300MW and 600MW turbine generators, and the corresponding measures taken in the design, implementation process and quality inspection. In addition to the design structure process, the cleanliness is also affected. An important cause of generator quality failure. It is mainly about the assessment of indicators and rewards and punishments.
3. Verify the replacement of the tester
During the manufacturing process, the inspection tester and the instrument for running online testing should reach the international advanced level. In the manufacturing process of steam turbine generators, the key processes such as stator burr burrs, film measurement methods and instrument updates, there are local hot spots after iron core stacking, in addition to the traditional winding current to achieve the rated magnetic density, with heat In addition to the image inspection, the ELCID instrument is used to measure and compare the measurement data of each core. Some solid wires are also eddy-detected. On-line detection, such as fiber winding vibration at the end of the stator winding, more effective water leakage alarm, fatigue damage life detection of torsional vibration axis, generator insulation life prediction and fault warning system.
(II) Renovation design of 300MW and 600MW steam turbine generators and consider designing and developing 800MW 3000r/min turbine generators.
Carry forward the spirit of innovation and absorb new experiences from abroad, and carry out new series design or modular design of 300MW, 600MW and 800MW on the basis of the development of new materials and new technologies in the 21st century. The new series should first be combined with the development of China's power grid on the basis of the components with the best reliability of domestic operation, to meet the needs of various operating conditions, and to properly consider the possible requirements in the international market. Simplify structure and process, reduce costs and shorten manufacturing time.
(3) Cooperating with steam turbine reconstruction, 125MW, 200MW and 300MW improve output and perfection.
(4) Cooperating with gas turbine power generation peak shaving and gas combined cycle technology to improve the capacity of dual-water internal cooling turbine generators to withstand peaking and shutdown, and to develop large-capacity air-cooled steam turbine generators.
The development of gas power peaking units, or the development of integrated gasification combined cycle (IGCC) and pressurized fluidized machine tool combustion combined cycle must develop gas turbine generator sets (GT), currently GT units between 50MW ~ 300MW, within this range The hydrogen-cooled steam turbine generator set that was commonly used in the world. Hydrogen-cooled generator sets have complicated start-ups and high requirements for operators. Therefore, since the 1980s, some foreign motor manufacturing companies have developed 50MW-250MW air-cooled steam turbine generators, and the capacity of air-cooled generators has increased from 50MW to 250MW. Left and right, the main measure is the use of thinned, thermally conductive insulation and vacuum solventless pressure (VPI) immersion and improved ventilation systems for stator winding insulation. The air-cooled turbo generator system is the simplest. It has no complicated structure of hydrogen charging, hydrogen discharge and hydrogen oil sealing. It is easy to operate and maintain, and there is no danger of hydrogen explosion. The disadvantage is that the stator winding temperature is high, the copper-iron temperature difference is large, and the efficiency is higher. The hydrogen cooling is low, the ash is easily accumulated in the rotor copper wire, and the effective part of the generator is large in size. The stator windings of modern large-scale steam turbine generators are mostly water-cooled, and the maximum temperature of the stator winding copper is generally below 90 °C. The temperature difference between copper and iron is very small. The stator windings of air-cooled turbine generators are cooled by pressurized air to generate electricity. The ventilation loss of the machine will be too large. The thermal conductivity of air is low (7 times smaller than the thermal conductivity of hydrogen pressure) and the air density is high (10 times that of hydrogen) under the same pressure. As a result, in an air-cooled generator, when the same amount of heat is dissipated It requires more volume of air and has a large ventilation loss. If the end of the rotor winding of the large-capacity air-cooled turbo generator is not internally cooled, the hot spot temperature is higher. If the end is cooled by internal cooling, the ash accumulation problem will be more difficult to remove than the groove.
China has 500-600 water-air-to-air turbine generators operating in power stations. Many power plants have installed and operated dual-water internal and cold steam turbine generators, and the rotor shaft windings have low temperature rise and insulation life. Long, the rotor coil is not easily deformed, and the insulation between the turns of the rotor coil is not in contact with the cooling medium, and it does not move or short-circuit with foreign matter, and the operation is reliable. Although the structure of the stainless steel rotor water diversion foot has been tested and can withstand the 10,000-time start of the unit, there is no practical experience of long-term peak-shaving operation. From the 100MW gas generator (hydrogen cooling) group installed by Shanghai Zhabei Power Plant in recent years, after running for more than 900 times in two years, the fatigue fracture of the thin copper skin at the joint between the rotor lead and the rotor coil occurred in July 1997, and there are foreign countries. The experience reported in the literature is that the stator and rotor windings are prone to damage after the peaking operation. Whether it is a dual-water internal cooling generator or an air-cooled turbo generator, the adaptability of the design structure must be re-examined.
It is necessary to cooperate with the development of gas turbine-generator set in China, and use double-water internal-cooled steam turbine generator and air-cooled steam turbine generator to analyze and demonstrate in the range of 50-250MW. In any case, at present, foreign markets need air-cooled steam turbine generators of this capacity range, and we should be able to design and manufacture. Therefore, in the 21st century, one of the manufacturing directions of large-scale steam turbine generators in China is to cooperate with the development of gas turbines-generator sets. While researching and improving the dual-water internal cooling turbine generators, it is also necessary to study the design and development of large-capacity air cooling. Turbine generator.
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