A new method for locating partial discharges in transformers

A novel method for determining the axial location of partial discharges in cast coils is presented. A signal processing algorithm is used to determine the normalized energy as a function of position along the coil. The normalized energy is interpreted in terms of the attenuation of the electromagnetic emissions from the partial discharges along the axis of the transformer. A plot of the attenuation as a function of distance along the length of coil clearly indicates the location of the partial discharges. It is concluded that the asymptotic maximum-likelihood estimate of the energy profile is an effective means for localizing partial discharge sites in the winding sections of a cast coil. >