CN201013535Y - Non-grid-connected large-scale wind turbines for high energy-consuming industries - Google Patents

Abstract

The utility model is a non-parallel-network large-scale wind power generator of high energy consumption industry. The device is designed based on the large or middle scale wind power generator, with canceling the much more expensive control circuit and device and high speed gear case, which are used for stabilizing the pressure, the frequency or the phase and so on. The design can simplify the speed-adjusting device for the impeller. The device comprises an impeller consisting of a vane and a wheel boss, a speed-adjusting device, a generator, a tower support and a direction-adjusting device. The impeller drives the generator with the direct driving mode or semi-driving mode. The electricity from the generator is the direct current. The device has the advantages of simpler in the structure, less in the components, lower in the fault ratio and lower in the manufacture cost and so on. The design makes the integrated cost for the device decreases to less than 0.2 Yuan per degree from the 0.5-0.6Yuan per degree at present. The device is very benefit for producing and manufacturing the wind power generator in volume-produce and is also good for developing the wind electricity industry. Besides, the device is also benefit to realize the target to build a high-energy consumption, and low cost green heavy chemical base in the littoral of the east of China first.

Description

Non-grid-connected large-scale wind turbines for high energy-consuming industries

technical field

The utility model relates to a wind power generator, in particular to a non-grid-connected large-scale wind power generator directly used for high energy-consuming industries, which belongs to the field of power supply or power distribution.

Background technique

Wind energy is the cheapest, most convenient, and cleanest renewable green energy used by human beings. Wind power generation, which converts wind energy into electrical energy, has attracted more and more attention from all over the world. The technology and equipment of high-power wind power generators have basically matured. At present, the use of large-scale wind power mainly depends on being connected to the mains grid and then delivered to users. The wind power that can be connected to the mains must meet its frequency, phase and voltage. Both should be the same as the mains power, and at the same time, the impulse current value of the generator to the grid at the moment of grid connection should be limited within the specified range (generally less than 1.5 times the rated current), so that it can get a smoother grid connection transient state The process can be connected to the grid. Existing large-scale wind generators are variable-speed constant-frequency horizontal-axis wind generators, and their structures are mainly composed of wind wheels, low-speed couplings, speed increasers, high-speed couplings, generators, towers, speed control devices, Steering devices, brakes, etc., many of which are designed to be very complicated to be connected to the mains grid. For example, the blades in the wind wheel must be designed as variable-pitch blades or fixed-pitch blade-tip variable-pitch There are several kinds of blades with dampers and other blades, and they must be used together with the speed regulating device to make the wind wheel work normally by adjusting the speed within the range of small changes in wind speed (such as 5-12m/s); The frequency of the mains power grid is 50HZ, and the speed of the wind rotor is low. In order to match the generator, a speed increaser must be connected between the low-speed coupling connected to the wind rotor and the high-speed coupling connected to the generator. The speed increase of the speed increaser is generally dozens of times, and multi-stage gear speed is required. The weight of the gear box can reach several tons, which makes the structure of the generator complex and expensive. The matching of control systems such as phase stabilization will cause the price of wind power to be higher than the price of grid power. If there is no government support, there will be no price advantage. However, even if various measures including reducing power generation efficiency are taken, parameters such as wind power frequency will still change greatly due to the large fluctuation of wind speed and other reasons. The proportion in the grid is often limited to 5%. Wind power is a kind of power source that is controlled by wind speed and is different from conventional power sources. It is mainly manifested in the following aspects:

(1) The wind speed fluctuates and changes randomly, so the electric energy generated by the wind turbine also fluctuates. Although such fluctuations can be controlled or predicted, at present, most of them are uncontrollable or the control effect is extremely weak. This increases the uncertainty and complexity of dispatching by grid dispatchers.

(2) There are various forms of generators in wind turbines, such as asynchronous generators, synchronous generators or double-fed induction generators. Therefore, the reactive power characteristics are complex, which brings about the deviation of the grid voltage, which requires that the reactive power compensation and output voltage automatic adjustment system should be considered in the grid design, so as to reduce the impact on the grid.

(3) The technical characteristics of wind power generation do not match conventional power generation, and the existing power system operation specifications are not applicable, and it is necessary to improve and supplement wind power characteristics.

(4) Due to the different characteristics of wind power generation technology, it is required to formulate corresponding regulations and control regulations according to the characteristics of wind turbine technology.

(5) The location of wind farms is generally far away from the load center and conventional power plants. This is a common phenomenon in the construction of domestic wind farms. Regions rich in wind energy resources are often far away from major power demand areas, which brings difficulties to the transmission of wind power, which means that the existing grid structure or framework needs to be transformed and changed, such as expanding the grid, and this is not just to replace some equipment can be achieved. All over the world, grid expansion is a big problem. On the one hand, it leads to an increase in the cost of wind power. On the other hand, large-scale transformation of the transmission system will also delay the connection and use of wind power. For example, many wind power projects in areas rich in wind energy resources in the north of the UK often take ten years to update the power grid during the period from commissioning to actual grid-connected power generation.

Therefore, the integration of wind power and grid power will have a relatively large negative impact on the grid. These impacts mainly include:

(1) The impact of large changes in wind power output power on the grid

From the point of view of the impact on the power grid, the first characteristic of wind power generation is that its output fluctuates greatly, and it fluctuates irregularly, which is difficult to predict. It can be seen from the output power expression of the wind turbine that the output power of the wind turbine is proportional to the swept area of the blades of the wind turbine, proportional to the air density, and proportional to the cubic function of the wind speed. After the model of the wind turbine is determined, the swept area of the blades remains unchanged, and the air density does not change much in a fixed area, but the wind speed changes considerably and is random, so the output power of the wind turbine varies mainly caused by changes in wind speed. According to the operating experience of wind farms in the United States, even a wind farm consisting of dozens of wind turbines usually has a maximum output power variation of about 40% within one minute.

(2) The influence of wind power generation on the reactive power of the grid

In a DC circuit, the voltage multiplied by the current is the active power. But in an AC circuit, the voltage multiplied by the current is the apparent power, and a part of the power (that is, the active power) that can do work will be less than the apparent power.

(3) The influence of wind power on the grid-connected power flow distribution

Due to the uncontrollable discontinuity of wind power generation, no matter how it is connected, the impact on the power flow distribution of the regional power grid is obvious. Connected to the grid at a high voltage level, the influence of the power flow distribution is small, but it cannot realize the nearby digestion of electric power.

(4) The influence of wind power generation harmonics on the power grid

"Harmonic pollution" has become one of the three major public hazards in the power grid. For an ideal generator, its electromotive force can be considered to be pure sine, that is, it does not contain high-order harmonics. Due to the particularity of wind power, harmonics are more harmful to the connected grid. The main harm of harmonics to the line is to cause additional loss. Harmonics can cause the inductance and capacitance of the system to resonate and amplify the harmonics. For example, at a certain harmonic, it may cause resonance, which may amplify the harmonic current several times or even dozens of times. The resonance of the power grid may cause equipment overvoltage. Harmonic overcurrent is generated, causing harm to equipment. When harmonics cause system resonance, the harmonic voltage increases and the harmonic current increases, causing relay protection and safety automatic devices to malfunction, damaging system equipment (such as power capacitors, cables, motors, etc.), causing system accidents and threatening safe operation of power systems. Harmonics also interfere with communication equipment, increase the power loss of the power system (such as line loss), and cause reactive power compensation equipment to fail to operate normally, bringing harm to the system and users.

(5) The impact of wind power grid connection on the system

After the wind power is connected to the system, it will not only affect the power flow distribution of the power grid, but also cause the asynchronous generator to generate an inrush current when it is connected to the grid because the double flux linkage of the internal inductance of the generator cannot be mutated. The height is related to the size of the slip when connecting to the grid. The greater the slip, the longer the AC transient attenuation time, and the greater the effective value of the impulse current when connecting to the grid.

(6) Impact on the power quality of the public connection point (PCC point)

The impact of wind power generation on PCC points is mainly caused by steady-state voltage fluctuations, voltage flicker, harmonic voltage unbalance, transient voltage dips or sags, etc. From the current operating experience in some areas, the network problems caused by a large number of wind power introductions are mainly weak The voltage problem of the system, followed by problems such as flicker and harmonics.

The above analysis shows that, due to the limitation of technical conditions and the requirements of power grid stability, the main components of wind turbines in my country still rely on imports, and they also need to be matched with very expensive control systems such as voltage stabilization, frequency stabilization, and phase stabilization. Make wind power equipment and wind power expensive and difficult to drop. By the end of 2005, 31 wind farms in my country had been put into normal operation, with a wind power installed capacity of 1.26 million kilowatts, but almost all of these wind farms were at a loss. The current cost of wind power is about 0.5-0.6 yuan/kWh, which is higher than the cost of thermal power and higher than that of hydropower. At present, 6 wind farms have been approved and under construction in Jiangsu Province, with a total installed capacity of 1.25 million kilowatts. Once completed and put into operation, the benefits will be difficult to guarantee, and the business prospects are not optimistic.

On the other hand, high-energy-consuming industries such as electrolytic brine in the chlor-alkali industry, electrolytic aluminum, electrolytic copper and other metal smelting processes need to consume super-large current direct currents that are allowed to fluctuate within a certain range, and these super-large current direct currents are currently mainly It is still provided by the mains power grid, so that the mains power grid cannot alleviate this heavy burden under the situation of insufficient power supply.

purpose of invention

The purpose of this utility model is mainly to overcome the shortcomings of the above-mentioned existing large-scale wind power generators connected to the mains power grid, which are quite complicated in structure, too high in cost, and the cost of wind power remains high. According to the needs of the above-mentioned high energy-consuming industries The extra large current is the actual situation that allows the direct current to fluctuate within a certain range. In the case of meeting the needs of high-energy-consuming industries, design a high-level localization with simple structure, low production cost, large effective wind speed range, and high power generation efficiency. Non-grid-connected large-scale wind turbines for high-energy-consuming industries.

The non-grid-connected large-scale wind power generator for high-energy-consuming industries of the utility model is mainly based on various existing large and medium-sized wind power generators, and uses very expensive wind power generators for voltage stabilization, frequency stabilization, phase stabilization, etc. The control circuit and control device directly cancel or reduce the precision requirements to reduce costs, directly cancel or replace the multi-stage high-speed gearbox with complex structure or replace it with simple low-speed transmission, and use multiple generators to connect to power generation in a timely manner. To expand the effective range of wind speed and improve power generation efficiency, its structure includes an impeller composed of blades and hubs, a speed regulating device, a generator, a tower and a steering device. The impeller-driven generator is a direct drive or semi-direct drive, that is The shaft of the wind rotor is directly connected with the shaft of the generator or connected with the shaft of the generator after a low multiplier, and the electricity generated by the generator is a direct current output. The multiplier of the low-magnification speed is generally not greater than 10 times. The number of said generators can be set arbitrarily according to needs, and can be 1 or 2 or more than 2. When there are 2 or more generators, the rotor shafts between the generators are connected in series or in parallel through clutches. Or series-parallel connection, when the wind speed is low, a single stage or a small number of motors cut in to work, when the wind speed is high, multiple motors cut in step by step until full load power generation. In order to further improve the power generation efficiency, the generator used is preferably a permanent magnet rotor generator.

The non-grid-connected large-scale wind power generator for high-energy-consuming industries of the present utility model is mainly based on the fact that the extremely large current required by high-energy-consuming industries is a direct current that can fluctuate within a certain range, and there is no frequency requirement for the voltage, so In the motor manufacturing, the heavy speed-up gearbox can be eliminated, and the generator shaft is directly connected to the wind rotor shaft or connected to the wind rotor shaft through a single-stage low-speed speed-up. The rotor speed can be changed with the wind speed, and the frequency of its alternating current can also It can be changed accordingly without affecting the use, because these alternating currents with variable frequency can be easily rectified into direct current by the rectifier, and then sent to the enterprise for direct use in industrial production. The elimination of the gearbox can not only reduce the cost, but also reduce the transmission link and its losses, this alone increases the output power by about 8%. It can also directly cancel the very expensive control circuits and control devices for voltage stabilization, frequency stabilization, and phase stabilization that are set up in large-scale wind turbines to be connected to the mains grid, and can also simplify the speed regulating device of the impeller, etc. It can conveniently connect the DC output voltage of several typhoon motors in the wind farm to the grid and transmit it to a remote place for use. If necessary, the inverter can also be used to invert the DC power into AC power with the same frequency as the mains power for daily life. use electricity. The non-grid-connected wind turbine has the advantages of simple structure, few parts, low failure rate, and low production cost. It can be completely modified on the basis of various existing large-scale wind turbines, which is very conducive to mass production Manufacture wind turbines and rapidly develop wind power business. The use of multiple generators to gradually cut into power generation at high wind speeds not only increases the power generation, but also expands the effective use range of wind speeds, and is more conducive to greatly reducing electricity prices, so that the comprehensive cost of wind power can be completely reduced from the current 0.5-0.6 yuan / It is very conducive to the completion of Jiangsu Province's goal of building a green heavy chemical base with high energy consumption, low cost, strong international competitiveness and Chinese characteristics in the eastern coast of my country.

Description of drawings

Accompanying drawing 1 is a kind of structural representation of the utility model;

Accompanying drawing 2 is another kind of structural representation of the utility model;

Accompanying drawing 3 is the wind speed/power diagram of taking two generators as an example in the utility model.

Detailed ways

See attached drawings 1 and 2, 1 in the figure is the blade, 2 is the hub, 3 is the speed control device, 4 is the tower, 5 is the machine room, 6 is the wind wheel shaft, 7 is the coupling, and 8 is the steering device , 9 is the first generator, 10 is the clutch, 11 is the second generator, 12 is the third generator, 13 is another clutch, 14 is the fourth generator, and 15 is the transmission gearbox. Figure 1 is a schematic diagram of the structure of two generators directly connected to the wind rotor shaft, and more generators can be connected in series sequentially. Figure 2 is a schematic diagram of the structure of connecting four generators in series and parallel with the shaft of the wind wheel through the transmission gear. More generators can also be connected in series and parallel. The specific number can be integrated according to factors such as the local wind volume and the power of the generators. Consider that if the air volume is large and the power of the generator is small, more generators can be used, otherwise, fewer generators can be used. The multi-stage high-speed gear box with complex structure is directly canceled or changed to a low-speed transmission with simple structure, and multiple generators are used to connect to power generation in a timely manner to expand the effective range of wind speed and improve power generation efficiency. The structure of the generator set is mainly It includes an impeller composed of blades 1 and hub 2, a speed regulating device 3, a generator 9, a tower 4 and a steering device 8, and the impeller-driven generator 9 is a direct-drive or semi-direct-drive type, that is, the wind wheel shaft 6 directly It is connected with the shaft of the generator or connected with the shaft of the generator after a low multiplier, and the electricity generated by the generator is a direct current output. The multiplier of the low-magnification speed is generally not greater than 10 times. The number of said generators can be set arbitrarily according to needs, and can be 1 or 2 or more than 2. When there are 2 or more generators, the rotor shafts between the generators are connected in series or in parallel through clutches. Or series-parallel connection, when the wind speed is low, a single stage or a small number of motors cut in to work, when the wind speed is high, multiple motors cut in step by step until full load power generation. In order to further improve power generation efficiency, it is best to use a permanent magnet rotor generator as the generator, which does not require external excitation, which greatly saves costs, not only makes the overall control simple, but also improves the power generation efficiency and power generation, and the failure rate Low and easy to maintain. The electricity generated is a DC output. If an AC generator is selected, only a rectifier is needed to rectify the AC power into a DC output. The very expensive voltage stabilization, frequency stabilization, and phase stabilization specially designed for grid connection with the mains grid will be used. All other control systems are omitted, so that the control is simple, and the load can be used to automatically adjust the engine load. When the wind speed decreases, the fan speed decreases, the output voltage and current decrease, and the power of the generator also decreases. The load is automatically lowered to make the motor On the contrary, when the wind speed increases, the fan speed increases, the output voltage and current increase, the power of the generator also increases, and the load is automatically increased to reduce the motor speed. That is to say, the wind turbine can automatically adjust the motor speed by using the DC load when the wind force does not change too much, keep the fan running, greatly reduce the operating frequency of the speed control device, and prolong the service life of the wind turbine.

Figure 3 is a schematic diagram of the output power of two 750KW generators when the wind speed is 5-25m/s. It can be seen from the figure that when the wind speed reaches 8.5m/s, the first generator can output 750KW at full load. When the wind speed reaches 11m/s, the second generator is connected to generate electricity. When the wind speed reaches 13m/s-16m/s, the two generators can output 1500KW at full load, which doubles the power generation efficiency. Directly used in seawater desalination, hydrogen production, and production of chlor-alkali, electrolytic aluminum and other high-energy-consuming industries, providing a large amount of low-cost energy for high-energy-consuming industries, promoting the rapid development of high-energy-consuming industries, and promoting the rapid development of wind power. It also reduces the heavy burden on the utility grid. It can also conveniently connect the DC output voltage of several typhoon motors in the wind farm to the grid and transmit it to a distant place for use. If necessary, the inverter can also be used to invert the DC power into AC power with the same frequency as the mains for daily use. Electricity for life. It makes high-power wind power, which lacks stable frequency output and has always been considered garbage power, become an inexhaustible gold power that is cheap, high-quality, green and environmentally friendly.

Claims (5)

1. A non-grid-connected large-scale wind power generator for high energy-consuming industries, comprising an impeller formed by blades and a hub, a speed regulating device, a generator, a tower and a steering device, and it is characterized in that the impeller-driven generator is Direct drive or semi-direct drive, that is, the shaft of the wind rotor is directly connected to the shaft of the generator or connected to the shaft of the generator after a low speed increase, and the electricity generated by the generator is a direct current output. 2. The non-grid-connected large-scale wind power generator for high energy-consuming industries according to claim 1, characterized in that the multiple of the low-speed speed-up is not more than 10 times. 3. The non-grid-connected large-scale wind power generator for high energy-consuming industries as claimed in claim 1 or 2, characterized in that the number of generators is 1 or 2 or more than 2, when the number of generators is 2 or When there are more than 2 generators, the rotor shafts between the generators are connected in series or parallel or series-parallel through the clutch. When the wind speed is low, the single-stage motor works. 4. The non-grid-connected large-scale wind power generator for high energy-consuming industries according to claim 1 or 2, wherein the generator is a permanent magnet rotor generator. 5. The non-grid-connected large-scale wind power generator for high energy-consuming industries as claimed in claim 3, characterized in that the generator is a permanent magnet rotor generator.

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