This part of IEC 60034-27 series deals with on-line PD measurements and provides a common basis with standardized procedures if possible for measuring techniques and instruments; the arrangement of the installation; normalization and sensitivity assessment; measuring procedures; noise reduction; the documentation of results; the interpretation of results; with respect to partial discharge on-line measurements on the stator winding insulation of non converter driven rotating electrical machines with rated voltage of 3 kV and up. This international standard covers PD measuring systems and methods detecting electrical PD signals. The same measuring devices and procedures can also be used to detect electrical sparking and arcing phenomena.