Localizing the source of partial discharges in large generators

This paper presents the preliminary results of a study to localize partial discharges in the stator of a generator. This is achieved by measuring the voltage between the stator's core and frame on several locations. Based on measurements done on a 23 MVA stator two algorithms were tested: the delay time technique and the top-top technique. The delay time technique assumes it takes time for the signal to travel through the stator. The top-top technique assumes the amplitude of the partial discharge is larger near its origin. The test results reported in this paper show that the delay time technique works better than the top-top technique.