Estimation of Weibull distribution parameters for partial discharge inference

The distribution of partial-discharge pulse height is examined on the basis of the Weibull function. It is shown that data fit a two-parameter Weibull function when partial discharges having the same nature, i.e. generated by the same type of defect, occur, while an additive mixed-Weibull distribution holds when partial discharge phenomena of two different natures are superimposed. The relationship between Weibull parameters and standard quantities, such as minimum and maximum PD amplitude, mean number of discharges, integrated charge magnitude per cycle and mean value of charge transferred by each pulse, are investigated. The proposed approach allows the time evolution of PD phenomena to be described with good accuracy