高压电机绕组大修后隐性温升故障机理与治理方案OA

To address the abnormal hidden temperature rise of the motor stator winding that cannot be detected by conventional electrical tests after a full rewind major overhaul of the high-voltage motor stator winding,a 560 kW/10 kV high-voltage motor was taken as a case study.Through theoretical analysis,on-site data monitoring,infrared thermography inspection,and re-view of the overhaul process,the fault mechanism was systematically analyzed.The research results indicate that the non-standard implementation of the vacuum pressure impregnation(VPI)process for the motor stator winding leads to the formation of a large number of closed air gaps between the stator winding and the stator core slot wall,which is the root cause of the sharp increase in contact thermal resistance and the blockage of the heat dissipation path.The loosening of the stator slot wedges and the blockage of the air ducts further aggravate the heat accumulation.Based on this,a comprehensive remediation scheme of"secondary impregnation+standardized fastening of the stator slot wedges+thorough cleaning of the motor air ducts"was proposed.After implementation,the tem-perature difference between the motor stator winding and the motor frame dropped from 55.9℃to 23.8℃,and the operating temperature rise fully met the specification requirements.