What if the wind meter malfunctions?
Many people do not realize that wind speed does not participate in the closed-loop control of wind turbine output.
In other words, how much torque the excitation control system adds to the generator is not determined based on the wind speed, but based on the impeller speed, which is an indirect variable.
This is because our current anemometer at the rear of the cabin cannot measure effective wind speed values. In fact, the wind speed cannot be described by a single number for the entire swept area of the impeller.
In most control systems, wind speed measurements can only be used to make logical judgments:
Is the wind speed high enough to allow the unit to start operating --- that is, the cut-in wind speed;
Whether the wind speed exceeds the tolerable range of the unit - that is, the cut-out wind speed;
Whether the wind speed has experienced extreme changes --- the so-called extreme wind condition detection.
It doesn't look complicated. But what happens if the anemometer fails?
In the first case, if this failure can be self-checked by the anemometer and reflected in the control system, it is usually a fault shutdown, which is the simplest case;
In the second case, the unit is in a shutdown state and the failure of the anemometer usually results in extremely low wind speed data, so the unit will not cut in;
In the third case, the unit is running on the grid, but the anemometer fails, causing the wind speed to be zero or too small. Because the general unit only judges that the wind speed is too high and cuts out, but if the wind speed is too low, no action will be triggered.
In this situation, it is relatively easy to get into trouble. Because if the wind speed is much higher than the cut-out wind speed without triggering the cut-out condition, the unit will be overloaded, which is very dangerous, especially in some extreme weather conditions.
Typically, wind speed measurements are less than 2 m/s due to ice on the anemometer, but the unit is operating at full capacity. If in this case, the wind speed continues to increase above the cut-out wind speed, but the unit continues to operate due to the failure of the wind speed measurement, it may cause potential overload damage to the unit, or a direct accident may occur.
Icing is just a typical example, and quality issues with the anemometer itself can also cause this phenomenon.
