How to deal with the problem that the fan power is too high or too low

1. Low power
  
If the generator power continues (generally set 30~60s), the reverse power, the value is less than the preset value Ps, the wind turbine will exit the grid and be in the standby state. The off-network action process is as follows: disconnect the generator contactor, disconnect the bypass contactor, do not release the tip spoiler, and do not put in mechanical brakes. If you re-cut, you can automatically increase the cut-off preset point by 0.5%, but when the speed drops below the preset point and then rises and then joins the grid, the preset value automatically returns to the initial state value.

The reconnection operation process is as follows: the generator contactor is connected, and the thyristor is fully turned on after the soft start. When the output power exceeds Ps3s, the bypass contactor is put into operation, and the speed cut point becomes the original value. When the power is lower than Ps, the thyristor path supplies power to the grid. At this time, the output current is not large, and the thyristor can work continuously.

This process is carried out at a lower wind speed. When the output of the generator is negative power, the power grid is absorbed, and the wind turbine has almost no work. If the cut point is not raised, it may still be the motor running state after starting.

2. High power

In general, the phenomenon of excessive power is caused by two situations: one is caused by fluctuations in the frequency of the power grid. When the grid frequency is reduced, the synchronous speed decreases, and the generator speed does not decrease for a short time, and the slip is large; the loss and the wind-switching mechanical energy do not suddenly change, so the power instantaneously becomes large. Second, due to climate change, the increase in air density. If the power is too high for a certain period of time, the control system should respond. It can be set to: when the generator output lasts for 10min and is greater than 15% of the rated power, it will stop normally; when the power lasts for 2s, it is more than 50% of the rated power, and it will stop safely.
    
Wind turbines exit the grid

The components of the wind turbine are limited by their physical properties. When the wind speed exceeds a certain limit, it is necessary to stop the network. For example, if the wind speed is too high, most of the blades will be severely stalled, and the shearing torque will exceed the tolerance limit, leading to premature failure. Therefore, when the wind speed exceeds the allowable value, the wind turbine should exit the grid.

The wind turbines exiting the grid due to excessive wind speed have the following conditions:

1) The wind speed is higher than 25m/s for 10min. In general, due to blade stall performance limitations, the generator speed does not rise when the wind speed exceeds the rated value. However, when the grid frequency rises, the synchronous speed of the generator rises, and the generator output must be kept basically unchanged. Only the original speed can be further increased, which may exceed the preset value. This situation can be quickly reacted by speed detection and grid frequency monitoring. If the speed is exceeded, the windshield should be winded 90° after the tip spoiler is released, so that the speed can be quickly lowered. Of course, as long as the speed does not exceed the allowable limit, only a normal shutdown is required.

2) The wind speed is higher than 33m/s for 2s and the machine stops normally.

3) The wind speed is higher than 50m/s, continuous ls, safe shutdown, crosswind 90°.

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