Influence of setting the hottest pitch angle and r

2022-08-12
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The influence of setting pitch angle and rated speed on power output

the pitch angle and speed of the blade of the fixed pitch wind turbine are fixed. This limitation makes only one point on the power curve of the wind turbine have the maximum power coefficient, which corresponds to a certain tip speed ratio. When the wind speed changes, the power coefficient also changes. In order to maintain the maximum power factor under the changing wind speed, the ratio of speed to wind speed must be kept unchanged, that is, the speed of wind turbine should be able to follow the change of wind speed. For the wind turbine driven by wind turbines with the same diameter, the rated speed of the generator can vary greatly, while the generator with lower rated speed has higher power coefficient at low wind speed; The generator with higher rated speed has a higher power factor at high wind speed, which is the basis for our use of two speed generator. It should be noted that the rated speed is not set according to the maximum power factor at the rated wind speed. Because the wind turbine is different from the general generator set, it does not often operate at the rated wind speed point, and the power is proportional to the third power of the wind speed. As long as the wind speed exceeds the rated wind speed, the power will rise significantly, which is simply uncontrollable for the fixed pitch wind turbine. In fact, the fixed pitch wind turbine has started long before the wind speed reaches the rated value. Next, we need to improve the efficiency of the industry and the entry-level cleaning method: improve the stall in the refueling sill in the horizontal tensioner oil tank, and the power coefficient at the rated point is quite small, as shown in Figure 3-5

on the other hand, changing the setting of blade pitch angle also significantly affects the output of rated power. According to the characteristics of fixed pitch wind turbines, we should try to improve the power coefficient at low wind speed and consider the stall performance at high wind speed. Therefore, we need to understand how the change of blade pitch angle affects the power output of wind turbine. Figure 3-6 shows the power curve of a group of 200kW wind turbines

the power curve obtained from both actual measurement and theoretical calculation can show that when the fixed pitch wind turbine is operating below the rated wind speed, we take the electro-hydraulic servo change fatigue experimental machine as an example. In the low wind speed region, the power curves with irregular shapes corresponding to different pitch angles are almost coincident. However, in the high wind speed region, the change of pitch angle has a very obvious impact on its maximum output power (rated power point). In fact, adjusting the pitch angle of the blade only changes the stall point of the blade to the air flow. According to the test results, the smaller the pitch angle, the higher the stall point of the air flow on the blade, and the higher the maximum output power. This is the basis that the fixed pitch wind turbine can adjust the blade installation angle under different air densities. Basis for adjusting blade installation angle under the same air density. (end)

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