There are two types of flicker emissions associated with
wind turbines, the flicker emission during continuous
operation and the flicker emission due to generator and
capacitor switchings. Often, one or the other will be
predominant. The allowable flicker limits are generally
established by individual utilities. Rapid variations in the
power output from a wind turbine, such as generator
switching and capacitor switching, can also result in variations
in the RMS value of the voltage. At certain rate and
magnitude, the variations cause flickering of the electric light.
In order to prevent flicker emission from impairing the voltage
quality, the operation of the generation units should not cause
excessive voltage flicker.