WO2011079484A1

WO2011079484A1 - Wind power supply method and system thereof

Info

Publication number: WO2011079484A1
Application number: PCT/CN2010/000450
Authority: WO
Inventors: 顾为东
Original assignee: 江苏省信息化研究中心
Priority date: 2009-12-30
Filing date: 2010-04-06
Publication date: 2011-07-07
Also published as: CN101741083A; CN101741083B

Abstract

A wind power supply method and a system thereof. The output voltage of each wind power generator in a wind power field (20) is converted by a DC/DC converter into a direct current voltage with the same voltage value as the others, and all the direct current voltages are connected with each other in parallel to constitute an independent wind power grid (10) of the wind power field (20). The wind power grid (10) directly supplies power to a high energy consumption load (40), or the wind power (grid (10) as a main power supply and a commercial power grid (50) as an auxiliary power supply together supply power to the high energy consumption load (40), or the wind power grid (10) is connected to the commercial power grid (50) via a DC/ AC inverter for supplying power to the high energy consumption load (40). The wind power supply method and system enable to reduce adverse effect to the power grid to a minimum.

Description

Wind power supply method and system thereof

The invention relates to a method for rapidly reducing greenhouse gas emissions and vigorously developing wind power, in particular, a method for breaking through the vigorous development of a wind power bottleneck, belonging to the field of power supply or power distribution.

Background technique

Today, global climate change has received widespread attention from countries around the world. From the latest acceleration of greenhouse gas emissions, by the end of the century, the Earth's climate will have a severe temperature rise of 6 to 7 °C, far beyond the Earth's ecological warning line of 2Ό. China, with its rapid economic growth, had a carbon dioxide emissions of 7.12 billion tons in 2008, accounting for about a quarter of the world's total emissions of 31.6 billion tons, surpassing the United States as the world's largest emitter of greenhouse gases. On the eve of the Copenhagen climate conference, the Chinese government promised to reduce its carbon emissions per unit of GDP by 40% and 45% in 2020, and it will face huge pressures to reduce carbon dioxide emissions in the future.

As one of the cheapest, most convenient and cleanest green renewable energy sources, wind energy provides an important alternative to coal to generate electricity and has great potential for CO2 reduction. China has abundant wind energy resources. It is estimated that the annual development of wind energy resources on land in China is around 24.7PWh, which is about 7 times of the current national electricity consumption. China also regards the development of wind energy as an important way to reduce carbon dioxide emissions. According to China's wind energy distribution characteristics, China has planned seven million kilowatt-class wind power construction bases in Inner Mongolia, Gansu and Jiangsu, and built a "human"-shaped wind power industry space centered on seven wind power bases with a capacity of over 10 million kilowatts. layout.

According to the data disclosed by the China Electricity Council, the total installed capacity of wind power in China has reached 12.21 million kilowatts in 2008, becoming the fourth wind power country in the world with more than 10 million kilowatts. At present, there are 5 million kilowatts of wind power. The base is actively preparing for construction or construction. If it is completed, China's wind power installed capacity will exceed 60 million kilowatts. With the new expansion of wind farms, the production capacity of wind power equipment in China has rapidly increased, and the total number of complete machine manufacturers has exceeded 70. The number of enterprises with an annual output of more than 100 large-scale wind turbines with a capacity of 1.5 megawatts has exceeded four. It can be seen from the above that the wind power industry is developing rapidly with its energy-saving and emission-reducing renewable green energy. A godsend opportunity, but because the existing large-scale wind power is used to load the national grid (referred to as the power grid or the municipal grid), that is: the integration of wind power and utility power is the only application of the world's large-scale wind farms. . The utilization of wind energy is mainly carried out according to the route of “wind turbine-generator-power grid-user (load)”, so that the grid becomes the load of wind power, and wind power can only supply power to users after being connected to the grid. In order to connect wind power with the mains, the wind farms are likely to be connected to the grid in accordance with the requirements of the State Grid’s “Technical Regulations for Wind Farms Connecting to the Power Grid” issued on July 30, 2009. At the same time, due to wind power The output power is subject to the change of wind speed, and has the intermittent and volatility synchronized with the wind speed. When the grid is connected to the grid, it will have many adverse effects on the grid operation and grid quality. Therefore, the total amount of grid-connected wind power is required to be without hydropower. The peaking of gas power generation shall not exceed 8% of the total grid. A ratio below 8% is the most important bottleneck that severely limits the development of wind power. and so In the second half of 2009, according to the reality of wind power integration, the National Development and Reform Commission made a decision on the overcapacity of wind power and the restriction on the production of wind power equipment, so that wind energy resources could not play their due role.

In addition, the wind power grid provides the wind turbine to meet the requirements of grid stability, voltage regulation and steady phase. In order to make the wind power meet the grid connection requirements, the wind power output from the wind turbine needs to be stabilized, stabilized and stabilized. The increase in wind turbine manufacturing costs and wind power prices has limited the large-scale application of wind power. In addition, the location of the wind farm is generally far from the load center and away from conventional power plants. This is a common phenomenon in the construction of domestic wind farms. Areas with abundant wind energy resources tend to be far away from the main areas of power demand, which makes it difficult to transmit wind power, which means that the existing power grid structure or framework needs to be modified and changed, such as expanding the power grid, etc., and this is not just replacing some Equipment can be realized, which in turn will further increase the cost of wind power. It is also an important reason for grid companies to be reluctant to purchase wind power. In the Renewable Energy Law, which was enacted in 2006, although it is stipulated that grid companies must purchase renewable energy in full, the grid is passive, not market economy rules, when the government imposes a mandatory purchasing policy. Buy wind power and connect to the grid.

In summary, the current method of using wind power and utility power to connect power to users, and making the power grid a wind power load has become the most important bottleneck restricting the development of wind power. If the bottleneck cannot be broken, it will It will make it difficult to achieve energy conservation and emission reduction through the development of wind power.

Summary of the invention

The main purpose of the invention is to break through the bottleneck restricting the development of wind power, and to provide a kind of development that can not only vigorously develop wind power, but also minimize the adverse effects on the power grid, and can also significantly reduce the cost of wind power, and generate huge economic and social benefits. A practical way to reduce wind power costs and break through the development of wind power bottlenecks.

Another object of the present invention is to provide a power supply system for implementing the above method.

The breakthrough of the invention is to develop a wind power bottleneck method mainly by converting the output voltage of each wind power generator in the wind farm into a DC voltage of the same voltage by DC/DC, and then parallelizing each other to form an independent wind power grid of the wind farm. The wind power grid directly supplies power to high-energy-consuming loads; or the wind power grid is the mainstay, supplemented by the municipal power grid, that is, when the night power is low, the city power grid can be the main, and the wind power grid is supplemented, and the city power grid is peak-adjusted. Co-operating for high-energy-consuming loads; or supplying the wind power grid to the high-energy load after being connected to the grid via the DC/AC inverter.

The breakthrough of the present invention is to vigorously develop a power supply system for a wind power bottleneck, including a power grid, a high energy load, a wind farm, and a wind turbine in the field thereof, characterized in that it further comprises an independent wind power grid and two sets of mode switching switches, The independent wind power grid is formed by converting the output voltage of each wind turbine in the wind farm into a DC voltage of the same voltage through a DC/DC DC converter and then connecting them in parallel with each other. The output voltage of the wind power grid is switched with the first group mode. The movable contact of the switch is connected, the first fixed contact of the first group mode switch is connected with the movable contact of the second group mode switch and the high energy load, and the third fixed contact of the first group mode switch The DC/AC inverter is connected to the city grid, and the city grid is connected to the second fixed contact of the second group mode switch via an AC/DC rectifier and a DC/DC converter. The high energy-consuming load is chlor-alkali industry, electrolytic aluminum industry, large-scale hydrogen production, wind/coal multi-energy system, seawater desalination, wind and gas integration, pumped storage and high-lift large-flow water delivery project.

The wind power generation system involved in the present invention is a direct current power generation system, and the wind power is connected in parallel to a direct current wind power grid. It and the grid, high energy load and mode switch constitute the four components of the method of the invention. The mode switching switch consists of two sets of high-power DC relays S1 and S2, which are used together to achieve the following three measures:

1) The first group mode switch S1 is closed with the wind power grid, the second group mode switch S2 is open, and the wind power grid is directly connected with the high energy load;

2) The first group mode switch S1 is closed with the wind power grid, and the second group mode switch S2 is connected to the city grid, and the wind power grid and the city grid are connected with the high energy load;

For these two measures, the DC wind power grid is not integrated into the existing national grid, ie the market power grid, but is directly or in conjunction with the municipal grid to supply power for high energy loads. It is characterized by a DC/DC DC conversion circuit connected to each wind turbine and grid power, through which the current of each branch is adjusted to realize the maximum wind energy capture and constant power output of the wind turbine and the grid power adjustment.

3) Connect Sl and S2 to the grid, wind power to the grid, and high-energy load for peak shaving.

In this measure, the wind power grid is inverted and merged into the public power grid. Due to the volatility and intermittent nature of wind, the volatility and intermittent nature of wind power affects the stability of local grid voltage and power quality. The high-energy industry's peaking of grid-connected wind power refers to the allocation of high-energy-consuming industries of corresponding scale for the wind farms. By adjusting the high-energy load power, it is consistent with the wind power fluctuations and reduces the proportion of wind power in the power grid. Therefore, the impact of wind power on the power grid is reduced, the wind power output power is smoothed, and the power supply stability and power quality of the downstream power grid are ensured.

The wind power grid of the invention directly supplies power to high-energy-consuming loads, digests in situ, reduces or completely eliminates the impact on the power grid, and breaks through the bottleneck of wind power grid-connected. It can not only vigorously develop wind power, but also minimize the adverse impact on the power grid, and it can generate huge economic and social benefits. It is a practical and feasible way to break through the bottleneck of vigorously developing wind power.

At the same time, because the wind power is composed of a direct current wind power grid and is directly connected to a high energy load, it can effectively reduce the wind power cost. Taking a 1.5 MW wind turbine as an example, in order to meet the requirements of frequency stabilization, voltage regulation and steady phase of the grid connection, a complex double-fed variable-speed constant-frequency generator set is adopted and a gearbox is used, and the present invention uses DC wind power generation. The system has no requirements on frequency and phase, can simplify the structure of the generator, and save the gearbox, which can reduce the total cost by about 20%. At the same time, the pitch control device can be canceled, the fixed pitch control is adopted, and the flow angle is controlled by The method achieves the purpose of controlling the tip speed ratio, which can reduce the cost by about 0%. The grid-connected controller can be reduced to a DC/DC DC converter to reduce the cost by about 8%, so that the total cost can be reduced by about 30-35%, and the probability of failure The simplification of the wind power system can be reduced by about 45%.

DRAWINGS

1 is a schematic structural view of a power supply system for vigorously developing a wind power bottleneck by the present invention; 2 is a schematic structural view of a wind power grid directly supplying power to a high energy load;

Figure 3 is a schematic structural view of a wind power grid and a municipal power grid jointly supplying power for a high energy load;

Figure 4 is a schematic diagram of the power supply structure in which the wind power is connected to the mains and the power is peaked by the high energy consumption load. In the above figures, G is a wind power generator, AC/DC is a rectifier circuit, and DC/DC is a DC conversion circuit.

DC/AC is an inverter circuit.

detailed description

The invention is further described below with reference to the accompanying drawings:

The high energy consumption load is the water electrolysis hydrogen production equipment of Tianjin Continental Hydrogen Equipment Co., Ltd.: FDQ~4/3. 2-IV type, the hydrogen production is 4m ³ /h, the rated power is 22kW, and the rated voltage is DC34V. The rated current is 550A. Power supply is selected from a 50KW wind turbine generator. The wind turbine can be purchased by Qingdao Fengwang Wind Turbine Co., Ltd., model FD18. 0- 50KW wind turbine with DC output voltage of 360V.

According to the characteristics of high energy load, DC/DC is a current type DC converter. The DC/DC converter uses a Buck circuit. The magnitude of the input impedance can be changed by controlling the duty cycle of the switching power supply, so that the output current of the generator can be controlled by changing the input power of the energy-consuming industry, and the load characteristics of the wind turbine can be changed to control the blade tip speed ratio. The rectifier circuit uses a controllable rectifier bridge. The circuit is adjustable in voltage by controlling six power switches.

Buck DC converter is used as the main circuit of the control system. IGBT is used as the main switch. The main technical parameters are: Operating frequency: 20kHz, rated input voltage: 360V, output voltage: 34V. The control system uses the power control system of Nanjing Quanle Technology Co., Ltd.

As shown in Fig. 1, the circuit diagram of the invention for reducing the cost of wind power and breaking through the bottleneck measures of the wind power grid is mainly composed of a wind power grid, a municipal power grid, a high energy load and a mode switch. The mode switch consists of two sets of high-power DC relays S1 and S2. S1 has 3 contacts 1, 2 and 3, 2 of which are empty contacts, S2 has 2 contacts 1 and 2, 1 of which are empty contacts, which together combine to form three kinds of power supply structure specific measures: The S1 is in contact with the 1 contact, the S2 is disconnected, and the wind power grid is separately connected to the high energy load to directly supply the high energy load, as shown in FIG. 2 . Each DC wind turbine is connected to a DC wind grid through a DC/DC DC converter. Each wind turbine dynamically adjusts the DC/DC converter current to control the generator electromagnetic torque in real time, so as to adjust the generator torque according to the wind turbine characteristic curve, achieve maximum power tracking when the rated wind speed is below, and achieve constant power output when the rated wind speed is above. .

The second is that S1 is in contact with contact 1, and S2 is in contact with contact 2. The wind power grid and the municipal grid jointly supply power for the high-energy load, as shown in Figure 3. After the AC/DC rectification and DC/DC DC conversion, the grid power is connected to the wind power grid, and the wind power grid and the municipal grid power supply complement each other to supply power to the high energy load. By controlling the current of the grid DC/DC converter, the grid power is adjusted. When the wind power is increased, the mains power is correspondingly reduced; conversely, the mains power is correspondingly increased; in the absence of wind power, the mains supply is used to maintain the minimum power required for production. Thus achieving high Stable, continuous and reliable power supply for energy-consuming loads. In particular, when power consumption is low at night, high-energy-consuming loads can also consume as much power as possible in addition to ensuring the use of all wind power, and the wind power grid is supplemented with the municipal grid power as the complementary power supply. The role of power grid peak shaving.

The third is that S1 is in contact with contact 3, S2 is in contact with contact 2, and the wind power grid is merged into the municipal grid through DC/AC inverter, and then the grid is electrically and subjected to AC/DC rectification and DC/DC DC conversion. The energy load is connected. As shown in Figure 4. By adjusting the current of the DC/DC converter connected to the high energy-consuming load, the high-energy load power is adjusted to be consistent with the wind power fluctuation, the proportion of wind power in the power grid is reduced, the wind power output is smoothed, and the power supply stability of the downstream power grid is ensured. And power quality.

For example, if a large wind farm outputs active power Ρπκ reactive power Qm, active power 1 and reactive power QL consumption of high energy load, according to the power balance theorem: Qeri Qn - QL

among them,? ^ and 3⁄4^ are the combined active and reactive power of the wind farm after peak shaving. It can be seen from the above formula that by adjusting the high energy-consuming load power to match the output power fluctuation of the wind farm, that is, P _D =PL at any time, the fluctuation of wind power is completely suppressed. In order to control the grid-connected power of the wind farm does not exceed 8% of the total capacity of the grid, the high-energy load power should be Q _n -8%P _C .

In order to achieve high energy consumption and negative power to follow the wind farm output power fluctuations, the wind power grid side converter 釆甩 regular inverter DC / AC control method to achieve decoupling control of active and reactive power. The high-energy load side DC converter DC/DC controls the active power of the DC bus. Its function is reflected in two aspects: On the one hand, the DC bus voltage is kept constant by active power regulation, and the tracking is given by the system. The active power reference signal is derived to achieve power coordination of the two PWM converters.

The method and the power supply system provided by the invention are practical breakthroughs capable of vigorously developing wind power, minimizing adverse effects on the power grid, and significantly reducing wind power costs and generating huge economic and social benefits. The best way to wind power bottlenecks. Because wind power technology is a mature technology, it only needs to overcome the existing concept and build wind power into wind power grid independently. It can no longer be restricted by the proportion of grid-connected network, and it can be developed because existing high-energy load is consumed. Most of the power supply in the city power grid only produces lower value-added loads. By changing such low-value-added high-energy-consuming loads to be mainly powered by the wind power grid, the existing urban power grid can reduce the burden. There is enough capacity to power urban and rural and high value-added loads. The goal of reducing the carbon emissions per unit of GDP for 2020 promised by our government will be 40% lower than that of 2005, providing effective and effective measures for global greenhouse gas emission reduction.

Claims

Rights request

1. A method for breaking through the bottleneck of vigorously developing wind power, characterized in that the output voltage of each wind turbine in the wind farm is converted into a DC voltage of the same voltage by DC/DC, and then connected in parallel to each other to form an independent of the wind farm. In the wind power grid, the wind power grid directly supplies power to high-energy-consuming loads; or the wind power grid is mainly used, supplemented by the municipal power grid, that is, when the night power is low, the city power grid can be the main, and the wind network is supplemented by the wind power network. Peak shaving, jointly powering high-energy loads; or powering the wind power grid to the high-energy load after being connected to the grid via the DC/AC inverter.

2. The power supply system of the method of claim 1, comprising a utility grid, a high energy load, a wind farm, and a wind turbine within the same, characterized in that it further comprises an independent wind grid and two sets of mode switchers, said independent The wind power grid is formed by converting the output voltage of each wind turbine in the wind farm into a DC voltage of the same voltage through a DC/DC DC converter and then connecting them in parallel with each other. The output voltage of the wind power grid and the first group mode switch The movable contact is connected, the first fixed contact of the first group mode switch is connected with the movable contact of the second group mode switch and the high energy load, and the third fixed contact of the first mode switch is DC The /AC inverter is connected to the city grid, and the city grid is connected to the second fixed contact of the second group mode switch via an AC/DC rectifier and a DC/DC converter.

3. The power supply system according to claim 2, wherein said high energy consumption load is chlor-alkali industry, electrolytic aluminum industry, large-scale electrolyzed water hydrogen production, wind/coal multi-energy system, seawater desalination, wind and gas integration Or pumped storage and high-lift large-flow water delivery projects.