Wind speed and wind direction measuring method for wind power generation system

Abstract

The invention discloses a wind speed and wind direction measuring method used for a wind power generation system, which is applicable to low wind speed zones. The method is characterized in that an anemoscope and a dogvane are installed on a tower under a wind wheel swept surface so as to measure wind speed and wind direction. The method is applicable to the low wind speed wind power generation system with the annual average wind speed ranging from 4m / s to 6m / s, vertical distances from the anemoscope and the dogvane to the wind wheel swept surface are at least 1.5 meters, and the diameter of the tower is twice that of the external edge of the tower. By adopting the method, the accurate measurement of the wind speed and the wind direction under the low wind speed environment can be guaranteed, and the problem that when the anemoscope and the dogvane are installed at the tail part of an engine room, inaccurate measurement of the wind speed and the wind direction can be caused due to the low-speed rotation of the wind wheel, can be avoided.

Description

technical field [0001] The invention relates to a wind power generation system, in particular to a method for measuring wind speed and direction of a low rated speed wind power generation system, and belongs to the technical field of wind power generation. Background technique [0002] The terrestrial wind energy resource area can be divided into four areas based on the annual average wind power density, namely the area rich in wind energy resources, the area rich in wind energy resources, the area with available wind energy resources, and the area with poor wind energy resources. Taking China as an example, the zoning of land wind energy resources and the percentage of the national land area are shown in Table 1. The area where China's land wind energy resources can be utilized accounts for about 76% of the country's land area. Table 1 shows the zoning of China's terrestrial wind energy resources and their percentages in the national land area. [0003] Table 1 [0004] ...

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Problems solved by technology

For use in low wind speed areas, due to the low fan speed (below 80rpm), it is difficult to meet the matching requirements with conventional high rated speed generators (150rpm and above), and the configuration of low rated speed generators has the disadvantages of large volume, weight and high cost. question

[0009] (3) For direct-drive wind motors, when the diameter of the impeller is too large, such as exceeding 10 meters, the rotational speed is high under occasional strong winds, and the safety hazard of the impeller is too large

[0010] (4) For existing wind turbine blade airfoils, the wind speed section of the best wind energy utilization coefficient is generally between 8 and 12m / s. Under low wind speed conditions, especially when the wind speed section is lower than 6m / s, the wind energy utilization coefficient Poor, it is difficult to maximize the capture of wind energy under low wind speed conditions

[0011] (5) Conventional medium and small power wind turbines generally use permanent magnet synchronous generators. Due to the cogging effect, when the generator starts or runs, it will generate a large starting torque, and the electromagnetic torque will generate pulsations.

At the same time, the application of the iron core increases the weight of the generator, and the existence of the iron core loss increases the loss

[0012] (6) The conventional wind power generation system installs the anemometer and wind direction indicator at the tail of the nacelle. Due to the continuous rotation of the measuring device and the turbulent flow at the tail of the blade under low wind speed conditions, the measurement of wind speed and wind direction is inaccurate.

[0013] To sum up, conventional high-rated wind-speed wind turbines are not suitable for areas with abundant wind energy resources and areas where wind energy resources are available. For low-wind-speed areas, it is necessary to develop suitable low-rated speed, high-efficiency, economical and reliable wind power generation systems. For efficient and reliable wind power conversion in low wind speed environments

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