The role of IEC 60034-27-5 for IEC 60034-18-41: Offline PD test methods with repetitive impulse voltage

This paper reviews relevant published IEC standards on converter-fed motor insulation and discusses some technical issues on offline PD tests methods with repetitive impulse voltage of IEC60034-27-5. In order to qualify PD-free insulation system for IEC 60034-18-41, the detail of PD testing method should be fixed as possible in IEC 60034-27-5, while there are still arbitrary factors in PD measurements: how to select impulse generator, tolerance against deformation and so-called ringing of impulse waveform, how to decide thresholds values for PD detection against disturbance from impulse generator and selection of RPDIV or PDIV for pass criteria judgements of IEC 60034-18-41.