Testing of Partial Discharges in Generator Coil Bars with the Help of Calibrated Acoustic Emission Method

Abstract

Investigation results of acoustic emission signals coming from partial discharges within chosen generator coil bar, in relation to measurement results of apparent charge introduced by partial discharges sources, are presented in the article. Analysis is based on amplitude distributions calculated for acoustic emission signals, ordered at difierent measuring points for difierent values of the supply voltage. In order to assign acoustic emission signal to its advance degree a descriptor named by an acronym ADP (deflned by authors) is calculated for each amplitude distribution. Descriptor families describing acoustic emission signals measured at particular measuring points (for difierent supply voltages) are presented in relation to apparent charge introduced by acoustic emission sources. These families concerning acoustic emission signals, measured at difierent measuring points for identical supply voltage, enable us to locate acoustic emission sources with maximum activity.