Measuring method of wind speed and direction in wind power generation system

Abstract

The invention discloses a method for measuring wind speed and direction for a wind power generation system suitable for low wind speed areas. The present invention is suitable for use in low-wind-speed wind power generation systems with an annual average wind speed of 4m / s to 6m / s. The vertical distance between the anemometer and wind direction indicator is at least 1.5 meters from the sweeping surface of the wind wheel, and the diameter of the tower is twice the outer edge of the tower. Adopting the present invention can ensure the accurate measurement of wind speed and wind direction under low wind speed environment, and avoid the problem of inaccurate measurement of wind speed and wind direction caused by eddy current caused by low-speed rotation of the wind wheel caused by installing the anemometer and wind direction meter at the tail of the nacelle.

Description

technical field [0001] The invention relates to a wind power generation system, in particular to a method for measuring the wind speed and direction of a low rated rotational speed wind power generation system, belonging to the technical field of wind power generation. Background technique [0002] The land wind energy resource area can be divided into 4 areas based on the average annual wind power density, namely the area with abundant wind energy resources, the area with abundant 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 onshore wind energy resources and the percentage of the national land area are shown in Table 1. The area where China's onshore wind energy resources can be used accounts for about 76% of the country's land area. Table 1 shows the zoning of China's onshore wind energy resources and the percentage of the country's land area. [0003] Table 1...

AI Technical Summary

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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