The Suppression of Impact Noise in Wind Turbine Gearbox Vibration Signal

Root mean square (RMS) of acceleration signal is one of the important parameters to monitor the wind turbine gearbox condition. Impulse noise appears with large energy and short time when gearbox suffers sudden change of wind speed and load. RMS error from data calculation influences the accuracy of condition judgment, so it is significant to filter impact noise which is non-periodic and random, which is regarded as small probability event in the whole gearbox operation time. The original vibration signal was processed by statistical method to draw histogram, mean and variance are obtained by the normal distribution. Normal data of signal, occupying an absolute proportion, was in the middle of the histogram. Impulse noise with high amplitude occupies a small proportion both sides of the histogram. At last, impact noise was eliminated from a field wind turbine vibration data by the criterion of $\mu\pm 3\sigma$, illustrating the effect of the proposed method.