Statistical variation of AC corona pulse amplitudes in point-to-plane air gaps

Using a multichannel analyzer, statistical variations of corona pulse amplitudes are studied for AC corona in point-plane air gaps. It is shown that, for each half cycle, corona pulse amplitudes generally follow a Gaussian type of probability distribution when the applied voltage is near the corona inception level. However, as the applied voltage is increased, the distributions show deviations from this behavior. Typical pulse amplitude parameters such as the average value, the standard deviation, and the coefficient of variation are measured for different experimental conditions, and the results for corona under AC voltages are compared with previously obtained results for DC corona