Question 2: A
Question 3: C
A generator usually consists of a stator, a rotor, an end cap . The seat and bearings and other components.
The stator consists of the seat . Stator core, wire wrapped windings, and other structural parts that hold these parts in place.
The rotor consists of a rotor core (with a magnetic choke. Magnetic pole winding) slip ring, (also known as the copper ring. Collector ring). Fan and rotor shaft and other components.
By the bearing and end cover of the generator stator, rotor connection assembly, so that the rotor can rotate in the stator, do cutting magnetic lines of motion, thus generating induced potential, through the terminal lead, connected to the circuit, the current is generated.
Turbine generator The generator that goes with the steam turbine. In order to get high efficiency, the turbine is generally made into a high-speed, usually 3000 rpm (frequency of 50 Hz) or 3600 rpm (frequency of 60 Hz). In nuclear power plants, the turbine speed is lower, but also above 1500 rpm. High-speed turbine generator in order to reduce the mechanical stress due to centrifugal force and reduce the wind friction consumption, the rotor diameter is generally made smaller, the length of the larger, that is, the use of long and thin rotor. Especially in the 3000 rpm or more high-capacity high-speed units, due to the relationship between the strength of the material, the rotor diameter is strictly limited, generally can not exceed 1.2 meters. And the length of the rotor body is subject to critical speed limitations. When the length of the body reaches more than 6 times the diameter, the second critical speed of the rotor will be close to the operating speed of the motor, operation may occur larger vibration. So the large high-speed turbine generator rotor size is subject to strict limitations. 100,000 kilowatts of air-cooled motor rotor size has reached the above limit size, to increase the motor capacity, only by increasing the electromagnetic load of the motor to achieve. For this reason, the cooling of the motor must be strengthened. Therefore, 5 ~ 100,000 kilowatts above the turbine generator are used in the cooling effect of hydrogen cooling or water-cooled technology. 70 years, the maximum capacity of the turbine generator has reached 1.3 ~ 1.5 million kilowatts. Since 1986, major breakthroughs have been made in the research of superconducting materials at high critical temperatures. Superconducting technology is expected to be applied in the turbine generator, which will produce a new leap in the history of turbine generator development.
[Edit]3. Diesel generators
Diesel generators Generators driven by the internal combustion engine. It starts quickly and is easy to operate. However, the internal combustion engine power generation cost is high, so diesel generator sets are mainly used as emergency backup power, or in mobile power stations and some large power grids have not yet reached the region. Diesel generator speed is usually below 1000 rpm, the capacity of a few kilowatts to several kilowatts between, especially 200 kilowatts below the unit more applications. It is relatively simple to manufacture. The output torque on the diesel engine shaft is periodically pulsating, so the generator is working under the condition of severe vibration. Therefore, the structural components of the diesel generator, especially the rotor shaft should have sufficient strength and rigidity to prevent these components from breaking due to vibration. In addition, in order to prevent the torque pulsation caused by the generator rotational angular velocity is not uniform, resulting in voltage fluctuations, caused by flickering lights, diesel generator rotor is also required to have a large moment of inertia, and should be so that the shaft system's intrinsic torsional vibration frequency and the diesel engine's torque pulsation of the frequency of any one of the alternating component of the frequency difference of 20% or more, so as to avoid the occurrence of *** vibration, resulting in the accident of broken shafts.
Diesel generator sets are mainly composed of diesel engines, generators and control systems, diesel engines and generators have two types of connection, one for flexible connection, that is, the use of couplings to the two parts of the docking up, the second is a rigid connection with high-strength bolts will be the generator steel connecting piece and diesel engine flywheel disk connected to the use of rigid connection is more more at present, diesel and generator are connected to the public installation in the public *** bottom frame, and then equipped with a variety of sensors, such as water temperature sensors, through these sensors, the running status of the diesel engine is displayed to the operator, and with these sensors, you can set an upper limit, when reached or exceeded the limit value of the control system will be pre-alarm, at this time, if the operator did not take measures, the control system will automatically shut down the unit, the diesel generator set is to take Diesel generator sets are adopted in this way to play a role in self-protection. The sensor receives and feeds back all kinds of information, the real display of these data and the implementation of the protection function is the control system of the unit itself.
[edit]4. Diesel generator principle
The diesel engine drives the generator to run, the diesel energy into electricity.
In the diesel engine cylinder, after the air filter filtered clean air and injector nozzles injected high-pressure atomized diesel fuel fully mixed, in the piston upward pressure, the volume shrinks, the temperature rises rapidly, reaching the ignition point of diesel fuel. Diesel fuel is ignited, the gas mixture burns vigorously, the volume expands rapidly, pushing the piston downward, known as 'work'. The cylinders according to a certain diesel generator order in order to work, acting on the piston thrust through the connecting rod into the crankshaft to promote the power of rotation, thus driving the crankshaft rotation.
Brushless synchronous alternator and diesel engine crankshaft coaxial installation, you can use the rotation of the diesel engine to drive the generator's rotor, the use of 'electromagnetic induction' principle, the generator will output induced electromotive force, through the closed loop of the load can produce current.
Only the most basic working principle of a genset is described here. A range of diesel engine and generator control and protection devices and circuits are also required to obtain a usable and stable power output.
Diesel generator set is an independent power generation equipment, refers to the diesel fuel, such as diesel engine as the prime mover to drive the generator to generate power machinery. The whole set is generally composed of diesel engine, generator, control box, fuel tank, starting and control battery, protection devices, emergency cabinets and other components. The whole can be fixed on the foundation, positioning use, can also be mounted on a trailer for mobile use. Diesel generator sets are non-continuous operation of power generation equipment, if continuous operation for more than 12h, its output power will be lower than the rated power of about 90%. Although the power of the diesel generator set is low, but because of its small size, flexible, lightweight, complete, easy to operate and maintain, so it is widely used in mines, railroads, field construction sites, road traffic maintenance, as well as factories, enterprises, hospitals and other departments, as a standby power supply or temporary power supply. At the same time, this small generator set can also be used as a small mobile power station, become a backup power supply for many enterprises to use.
[edit]5. Types
Because of the different forms of primary energy, can be made into different generators.
The use of water resources and turbines with the water turbine can be made into a water turbine generator; due to the reservoir capacity and head fall height is different, can be made into different capacity and speed of the water turbine generator.
The use of coal, oil and other resources, and boilers, turbine steam engine with, can be made into a turbine generator, this generator is mostly high-speed motor (3000rpm).
In addition, there are various types of generators that utilize energy from wind, atomic energy, geothermal energy, and tidal energy.
In addition, due to the different operating principles of generators are divided into direct current generators, asynchronous generators and synchronous generators. Currently in widespread use of large generators are synchronous generators.
[Edit]6.roller DC generator precautions
1, the purchase and use of generators, should be consistent with the technical requirements on the nameplate, such as voltage, power and rated output current. For example, for Harvest-27 tractor, Dongfanghong-40 tractor, etc., commonly used 150-watt generator, rated output current of 13 amps; for Tiehiu-55 tractor commonly used 220-watt generator, rated output current of 18 amps.
2, for the tractor generator is usually parallel excitation, that is, the generator excitation coil is connected in parallel, so there must always be an end through the casing and armature coil is connected in parallel, so there must always be an end through the casing and armature coil. If the excitation coil is connected to the armature coil through the casing inside the generator, it is called the internal lap (Figure 5-1), which is called "internal lap generator"; if the excitation coil is connected to the armature coil outside the generator through the regulator lap (Figure 5-2), which is called "external lap generator". External iron generator". Domestic tractor DC generator are currently used for internal iron. When wiring, be sure to connect the lead wire of the excitation coil to the carbon brush holder of the lap iron, the excitation coil will have no current through, the generator will not generate electricity. In addition, some imported tractors use external iron generator, if you change to internal iron generator, as long as the generator excitation coil tap wiring can be changed.
3, the generator shell on the two terminals, generally have "armature" "magnetic field" words indicate. If the text labeling is not clear, the following methods can be identified.
1) Armature terminal: thicker diameter; is connected to the insulated brush holder.
2) Magnetic field terminal: diameter is thin; magnetic field coil an end is pressed on it.
4, in the tractor generator is driven by the engine, so the direction of rotation is certain, in the overhaul if the generator will be rotated in the reverse direction will not generate electricity, this is because the positive rotation armature coil in the role of the magnetic field induced by the current through the regulator and the excitation coil connected. The direction of the magnetic field after energizing the excitation coil is the same as the direction of the residual magnetism of the iron core, thus the magnetic field is continuously enhanced and the voltage increases rapidly. Reversal of the current direction and positive rotation of the opposite direction, so that the direction of the magnetic field after the excitation coil is energized and the direction of the iron core remanent magnetism is opposite, the magnetic field is getting weaker and weaker, so that the generator can not generate electricity.
5, when the generator armature is not short-circuited by the load, the generating field is not burned out. This is because the DC generator used on the tractor are parallel-excited. Generator in the rated power work, the armature windings produce most of the current lost to the external circuit, a small part of the input excitation winding to produce a magnetic field. When the armature terminals and chassis short circuit, the generator current increases rapidly, at this time in the motor to produce a large voltage drop and a strong armature reaction, so that the output voltage drops sharply, the excitation current quickly disappears, the generator voltage tends to zero. Therefore, when the armature terminals and chassis short circuit will not burn the generator.
6, in use, sometimes found in the generator polarity suddenly change the phenomenon (that is, the direction of the current issued by the change). This is because the output current suddenly increased, the strong armature reaction within the motor to change the direction of the iron core residual magnetism caused. Encountering this situation must be changed to make the charging circuit work normally. The method of change is: connect the positive pole of the battery with the chassis, the negative pole and the magnetic field terminal touch 2-3 seconds, that can change the magnetic pole iron core remanent magnetism direction. (In systems with positive pole lapping). Sometimes, in the overhaul of the battery as a power supply, spark method to check the excitation coil faults, such as not paying attention to the polarity of the connection, the negative pole of the battery as the iron pole, changing the direction of the current in the excitation coil, thus changing the direction of the residual magnetism of the iron core. Due to the change in the direction of the residual magnetism, the generator voltage polarity is also changed. This should be noted.
7, the general DC generator rectifier copper mica sheet between the copper sheet are lower than the copper sheet. This is because the copper sheet than the mica sheet wear faster, use a period of time mica sheet will be higher than the rectifier copper sheet, so that the carbon brushes are suspended. This will result in strong sparks between the rectifier and the carbon brushes. In order to avoid this phenomenon, the mica should be cut lower than the rectifier copper by about 0.8mm after the rectifier is lightened by a saw blade. However, some DC generators such as ZF-28 and ZF-33 type, rectifier copper piece between the use of artificial mica, it is similar to the copper wear rate, so the factory did not cut the mica piece low, overhaul of this generator does not need to cut low.
[edit]7, synchronous generator
Synchronous motor for generator operation. Is one of the most commonly used alternator. In the modern power industry, it is widely used in hydroelectric power generation, thermal power generation, nuclear power generation and diesel power generation. Because synchronous generators generally use DC excitation, when its stand-alone independent operation, by adjusting the excitation current, can easily adjust the generator voltage. If connected to the grid operation, because the voltage is determined by the grid, can not be changed, at this time the result of regulating the excitation current is to regulate the power factor of the motor and reactive power.
The stator and rotor structure of synchronous generators is the same as that of synchronous motors, and generally adopts the three-phase form, and the armature winding adopts the single-phase only in some small synchronous generators.
Operating characteristics The performance of synchronous generators is mainly characterized by no-load characteristics and load operation characteristics. These characteristics are an important basis for the user to choose the generator.
No-load characteristics When the generator is not connected to the load, the armature current is zero, known as no-load operation. At this time, the three-phase winding of the motor stator only excitation current If generated by the no-load electromotive force E0 (three-phase symmetrical), the size of which increases with the increase of If. However, the two are not proportional because of the motor magnetic circuit core saturation phenomenon (Figure 1). The curve reflecting the relationship between the no-load electromotive force E0 and the excitation current If is called the no-load characteristic of the synchronous generator.
Armature reaction When the generator is connected to a symmetrical load, the three-phase currents in the armature windings produce another rotating magnetic field, called the armature reaction field. Its speed is exactly equal to that of the rotor, and the two rotate synchronously.
Synchronous generator armature reaction magnetic field and rotor excitation magnetic field can be approximated that are distributed according to the sinusoidal law. The spatial phase difference between them depends on the temporal phase difference between the no-load electromotive force E0 and the armature current I. The armature reaction field is also related to the load. The armature reactive magnetic field is also related to the load condition. When the load of the generator is inductive, the armature reaction magnetic field plays the role of demagnetization, which will lead to the generator voltage reduction; when the load is capacitive, the armature reaction magnetic field plays the role of helper magnetism, which will make the generator output voltage increase.
Load operating characteristics mainly refers to the external characteristics and adjustment characteristics. External characteristics is when the speed for the rated value, the excitation current and load power factor is a constant, the generator terminal voltage U and load current I relationship, as shown in Figure 2. The adjustment characteristic is the relationship between the excitation current If and the load current I when the rotational speed and terminal voltage are rated and the load power factor is constant, as shown in Fig. 3. Three types of loads, resistive, capacitive and inductive, are also shown in Fig. 2. The curves of the three are different due to the difference in the armature reaction to the magnetic field influence. In the external characteristics, the degree of change in voltage from no-load to rated load is called the rate of change of voltage ΔU, often expressed as a percentage
The rate of change of voltage of a synchronous generator is about 20 to 40%. General industrial and domestic loads require the voltage to remain essentially unchanged. For this reason, as the load current increases, the excitation current must be adjusted accordingly. Figure 3 shows the adjustment characteristics under three different types of loads. Although the trend of the adjustment characteristic is opposite to the external characteristic, for inductive and purely resistive loads, it is rising, while under capacitive loads, it is generally falling.
Structure and classification The structure of synchronous generators is divided into two types according to their speed: high speed and low (medium) speed. The former is mostly used in thermal power plants and nuclear power plants; the latter is mostly linked with low-speed hydraulic turbines or diesel engines. In terms of structure, high-speed synchronous generators mostly use hidden pole type rotor, low (medium) speed synchronous generators mostly use convex pole type rotor.
High-speed synchronous generator Because most generators and prime movers coaxial linkage, thermal power plants use high-speed turbines as prime movers, so the turbine generator is usually used with high speed 2-pole motors, its speed up to 3,000 rpm (in the grid frequency of 60 Hz, for 3,600 rpm). Nuclear power plants mostly use 4-pole motor, speed of 1500 rpm (when the grid frequency of 60 H, for 1800 rpm). In order to adapt to high speed, high power requirements, high-speed synchronous generators in the structure of a hidden pole type rotor, the second is to set up a special cooling system.
① Hidden pole rotor: cylindrical appearance, in the cylindrical surface groove to place DC excitation winding, and metal groove wedge fastening, so that the motor has a uniform air gap. Due to the huge centrifugal force during high-speed rotation, the rotor is required to have high mechanical strength. Hidden-pole rotors are generally forged from a single piece of high-strength alloy steel, and the slots are generally open to allow the installation of the excitation winding. In each pole pitch about 1/3 of the part is not slotted, the formation of large teeth; the rest of the teeth are narrower, known as small teeth. The center of the large teeth is the center of the rotor pole. Sometimes the large teeth also open some smaller ventilation slots, but not embedded in the winding; sometimes also in the embedded line slot bottom milling out a narrow and shallow groove as a ventilation slot. Hidden pole rotor in the rotor body axial ends are also equipped with metal ring guard and center ring. Guard ring is made of high-strength alloy thick-walled cylinder, to protect the excitation winding end from being thrown out by the huge centrifugal force; center ring to prevent the winding end of the axial movement, and support the guard ring. In addition, in order to the excitation current into the excitation winding, the motor shaft is also equipped with collector rings and brushes.
② cooling system: due to the motor in the energy loss and motor volume is proportional to its magnitude and the motor line level of three proportional to the motor, and the motor heat dissipation surface of the magnitude of the motor line level of the second party. Therefore, when the size of the motor increases (by material limitations, increase the capacity of the motor will have to increase its size), the motor per unit of the surface of the heat to be emitted will increase, the temperature rise of the motor will increase. In high-speed turbine generators, the centrifugal force will make the rotor surface and the rotor center hole surface produces huge tangential stress, the larger the rotor diameter, the greater this stress. Therefore, in the forging material allowable stress limit range, 2 pole turbine generator rotor body diameter can not exceed 1250 mm. Large turbine generator to increase the single machine capacity, only by increasing the length of the rotor body (i.e., with a slender rotor) and improve the electromagnetic load to solve. At present, the length of the rotor can be up to 8 meters, which is close to the limit. The only way to continue to increase the capacity of a single machine is to increase the electromagnetic load of the motor. This makes the heating and cooling problems of large turbine generators particularly acute. For this reason, a variety of cooling systems have been developed. For turbine generators below 50,000 kilowatts, mostly closed-circuit air cooling systems are used to cool down the heated parts by blowing the fan inside the motor. For generators with a capacity of 5 to 600,000 kilowatts, hydrogen cooling is widely used. Hydrogen (99% purity) of the thermal performance than air, it to replace the air not only good thermal effect, and can make the motor ventilation friction losses greatly reduced, thus significantly improving the efficiency of the generator. However, the use of hydrogen cooling must have explosion-proof and leak-proof measures, which makes the structure of the motor more complex, but also increases the consumption of electrode materials and costs. In addition, can also use liquid medium cooling, such as water for the relative cooling capacity of air 50 times, take away the same amount of heat, the required flow of water is much smaller than air. Therefore, in the coil using part of the hollow wire, wire cooling water, you can greatly reduce the temperature rise of the motor, delay the insulation aging, growth of motor life. 1956, the United Kingdom pioneered the first 12,000 kilowatts of stator coil water-cooled turbine generator. 1958, China by the Zhejiang University, Shanghai Electric Machinery Factory first developed into the first stator and rotor coils are used in the water-cooled 12,000 In 1958, China developed the first 12000 kW dual water-cooled turbine generator with both stator and rotor coils by Zhejiang University and Shanghai Electric Machinery Factory, laying the foundation for this kind of cooling method. Some countries in the world in the large-capacity motor also widely used water cooling technology, and manufactured hundreds of thousands to more than one million kilowatts of giant generators. In addition to water-cooled, liquid cooling medium can also be used transformer oil, its relative thermal conductivity of about 40% of water, good insulation properties, the generator can be increased to the rated voltage of several tens of thousands of volts, thus saving the investment in step-up transformers. In recent years, also studying the evaporative cooling technology with Freon as the cooling medium. Freon insulation is good, it is easy to gasification, the use of its latent heat of gasification to cool the motor, is a meaningful direction of exploration.
Low-speed synchronous generators Most of them are driven by lower speed hydraulic turbines or diesel engines. The number of motor poles from 4 poles to 60 poles, or even more. Corresponding speed of 1500 ~ 100 rpm and below. Because of the low speed, generally used on the material and manufacturing process requirements of the lower convex pole type rotor.
Each pole of the convex pole type rotor is often made of 1 to 2 mm thick steel plate stacked, riveted into a whole, the pole set of excitation winding (Figure 4). The excitation winding is usually made of flat copper wire winding. Magnetic poles of the pole boots are often equipped with a damping winding. It is a shorted loop formed by a bare copper strip in the damping groove of the pole shoe and a copper ring soldered to each end. Magnetic poles are fixed on the rotor yoke, which is made of cast steel. Convex-pole rotors can be divided into two types: horizontal and vertical. Most synchronous motors, synchronous regulators and generators towed by internal combustion engines or impact turbines use horizontal structure; low-speed, large-capacity hydro generators use vertical structure.
The rotor of a horizontal synchronous motor is mainly composed of the main pole, yoke, excitation winding, collector ring and rotor shaft. Its stator structure is similar to the asynchronous motor. Vertical structure must use thrust bearings to bear the gravity of the rotating part of the unit and the downward pressure of water. Large-capacity hydro generator, this force can be as high as four or fifty megabulls (equivalent to about four or five thousand tons of object gravity), so the structure of this thrust bearing is complex, the processing technology and installation requirements are very high. According to the placement of thrust bearings, vertical hydro generator is divided into suspended and umbrella type two kinds. Suspended thrust bearings are placed in the upper or middle part of the upper frame, which are more stable in mechanical operation when the rotational speed is high and the ratio of rotor diameter to core length is small. The thrust bearing of the umbrella type is placed on the lower frame below the rotor or on the top cover of the hydraulic turbine. The load frame is a lower frame of smaller size, which saves a lot of steel and reduces the height of the generator and plant counting from the base of the seat.
Parallel operation of synchronous generators The vast majority of synchronous generators are operated in parallel to generate electricity. Each parallel operation of synchronous generators must be frequency, voltage magnitude and phase are consistent. Otherwise, the moment of the parallel joint gate, the generators will produce internal circulating current between the generators, causing disturbances, and in severe cases, the generator will even suffer damage. However, two generators into parallel operation before, generally speaking, their frequency and voltage magnitude and phase is not exactly the same. In order to enable synchronous generators can be put into parallel operation, there must first be a synchronization process. Synchronization method can be divided into quasi-synchronous and self-synchronous two. After the synchronous generator is put into parallel operation, the load distribution of each machine is determined by the generator speed characteristics. By adjusting the governor of the prime mover and changing the rotational speed characteristics of the generator set, the load distribution of each generator can be changed to control the generating power of each generator. And by adjusting the excitation current of each generator, you can change the distribution of reactive power of each generator and regulate the voltage of the grid.
Quasi-synchronous parallelism will have been added to the excitation of the generator to be put into operation by adjusting the speed of the prime mover and change the excitation of the generator, so that the frequency difference between it and the generator in operation is not more than 0.1 ~ 0.5%. At the instant when the voltage phase difference between the two machines does not exceed 10°, the two can be automatically drawn into synchronous operation. Quasi-synchronous parallel operation can be manual, can also borrow automatic devices to complete.
Self-synchronous parallel The generator to be put into parallel speed to close to the synchronous speed of the grid, in the absence of excitation on the conditions of closing parallel, and then join the excitation, relying on the generator and the grid between the emergence of the loop current and the corresponding electromagnetic torque generated by the generator into synchronization quickly. The use of self-synchronous parallel, due to the reduction of generator speed, voltage and select the time required to close the moment, so the process of parallelization is faster, especially suitable for power system accidents in the case of emergency units into. However, this method in the parallel closing moment of the current impact is relatively large, will make the grid voltage drop for a short period of time, the motor winding end to withstand a large electromagnetic force.
8. How to solve the problem of poor output voltage accuracy of the alternator?
In our daily life, we use the alternator for the use of electrical equipment, often occurs when the electrical equipment can not work properly, the reason is that the alternator output AC power is not stable enough, this time the need for power regulators to stabilize the voltage, that is, our daily life is often used to the AC regulated power supply, AC regulated power supply can make the generator's output voltage precision stabilization of the normal operation of the electrical equipment to the range allowed. The AC voltage stabilizer can stabilize the output voltage of the generator to the range permitted by the normal operation of our power equipment.
[edit]9. Asynchronous generators
[6]Asynchronous generators are also known as "induction generators". The use of stator and rotor air gap between the rotating magnetic field and the rotor winding in the induction current interaction of a kind of alternator. Its rotor steering and rotating magnetic field of the same direction, but the speed is slightly higher than the synchronous speed of the rotating magnetic field. Commonly used as a small power turbine generator.
AC excitation generators are also known as doubly-fed generators
Three-phase asynchronous motors
. AC excitation generator due to the rotor side of the AC voltage excitation, so that it has a flexible mode of operation, in the solution of the power station sustained frequency overvoltage, variable speed and constant frequency power generation, pumped storage power station electric - generator set speed control and so on has a traditional synchronous generator can not be compared to the superiority of the problem. The main operation modes of AC excitation generator are as follows: 1) running in variable speed and constant frequency mode; 2) running in the mode of reactive power wide range adjustment; 3) running in the mode of power generation - electric.
With the increase in transmission voltage of the power system, the growth of the line, when the transmission power of the line is lower than the natural power, the line and the power station will be a continuous frequency overvoltage. In order to improve the operating characteristics of the system, a number of technologically advanced countries, in the early 6 "century A" era began to study the application of asynchronous generators in large power systems, and that the use of asynchronous generators in large systems can improve the stability of the system, the reliability and the economy of operation.
[Editorial][3]Prospects for the development of generators
The national supply of hydropower due to a number of reasons there is a serious shortage of electricity to a certain degree of restriction, and in recent years, it is China's rapid development of the industrial economy in recent years, many enterprises have to step up their efforts to put into large-scale production; followed by the first two years of the purchase of generators by a large number of manufacturers is for emergency purposes, in the purchase of the purchase is no Long-term planning, and things have changed the purchased small generators have not been able to adapt to the new needs, in this case, the replacement of generators also accounted for a large portion; then the annual export of electromechanical products are increasing, pumps and generators market space in recent years will be great. It is in the promotion of tripartite factors, hardware city pumps and generators market once again ushered in a new opportunity for development. [1]
Currently the most promising development is the wind turbine.
Wind energy as a clean renewable energy, more and more by the world's attention. Its reserves are huge, the total global wind energy resources of about 2.74 × 109MW, of which the wind energy can be utilized for 2 × 107MW. China's wind energy reserves are very large, widely distributed, only onshore wind energy reserves of about 253 million kilowatts, the development and utilization of huge potential.
With the development of the global economy, the wind energy market is also developing rapidly. 2007 global wind power installed total of 90,000 MW, 2008 global wind power growth of 28.8%, the end of 2008 the global cumulative installed capacity of wind power has exceeded 120,800 MW, equivalent to 158 million tons of carbon dioxide emissions reduction. With technological advances and the development of environmental causes, wind power generation will be fully commercially competitive with coal-fired power generation.
During the Tenth Five-Year Plan period, China's grid-connected wind power has been developing rapidly. 2006, China's cumulative installed capacity of wind power has reached 2.6 million kilowatts, becoming one of the major markets for the development of wind power generation after Europe, the United States, and India. 2007 has seen a continuation of the burgeoning growth in the scale of China's wind power industry. In 2008, China's new installed capacity of wind power reached 7,190,200 kilowatts, the new installed capacity growth rate of 108.4%, the cumulative installed capacity jumped over the 13 million kilowatts mark, reaching 13,242,200 kilowatts. Inner Mongolia, Xinjiang, Liaoning, Shandong, Guangdong and other places rich in wind energy resources, wind power industry development faster.
Since the second half of 2008, China's economic development has slowed down due to the international macro situation. In order to stimulate domestic demand and maintain stable and rapid economic and social development, the government has increased investment in fixed assets in the field of transportation and energy, and supported and encouraged the development of renewable energy. As energy-saving and environmentally friendly new energy, wind power industry to win the historic opportunity for development, in the financial crisis wreaked havoc in the unfavorable environment against the market, the momentum of development is rapid, as of the beginning of 2009, the country has 25 provinces, municipalities directly under the Central Government, autonomous regions with wind power installed.
China's wind and other new energy [5] development prospects are very broad, is expected to be a long time in the future will maintain a high rate of development, while profitability will also be with the gradual maturation of the technology to steadily improve. With the localization of China's wind power installation and the scale of power generation, wind power costs can be expected to fall again. Therefore, wind power began to become more and more investors for gold. Wind farm construction, grid-connected power generation, wind power equipment manufacturing and other areas have become investment hot spots, the market outlook is promising. 2009 total profit of the wind power industry will remain high growth, after the rapid growth in 2009, it is expected that the growth rate in 2010, 2011 will be slightly down, but the growth rate will reach more than 60%. 2010 national cumulative installed capacity of wind power is expected to exceed 20 million kilowatts, ahead of schedule to achieve the 2020 wind power industry, the wind power industry is expected to grow at a faster pace. million kilowatts, ahead of schedule to achieve the 2020 planning goals.
[edit]Types of generators
There are many types of generators. From the principle is divided into synchronous generators, asynchronous generators, single-phase generators, three-phase generators. From the generation method is divided into steam turbine generator, water turbine generator, diesel generator, gasoline generator and so on. From the energy source is divided into thermal generators, hydroelectric generators and so on.
[edit]Types of generators
[4]Because of the different forms of primary energy, different generators can be made.
The use of water resources and hydraulic turbines with, can be made into water turbine generators; due to the reservoir capacity and head fall height is different, can be made into different capacity and speed of the water turbine generator. The use of coal, oil and other resources, and boilers, turbine steam engine with, can be made into a turbine generator, this generator is mostly high-speed motor (3000rpm). There are also various types of generators that utilize energy from wind, atomic energy, geothermal energy, and tides. The use of diesel, gasoline and other resources as a source of energy diesel, gasoline generators are more widely used. In addition, due to the different operating principles of generators, they are divided into direct current generators, asynchronous generators and synchronous generators. Currently in widespread use of large generators are synchronous generators.