CBM of Transformers

CBM of Transformer includes CAss once at beginning & then Condition Monitoring (CM) of Transformer, Root Cause Symptom Analysis (RCSA) and Corrective Action – Preventive Action  (CAPA).

CBM = CAss + CA + CM + RCSA + CAPA

Procedure of CBM of transformer – Condition assessment is done at the beginning to learn about any  nonconformities. The condition is improved then by taking corrective actions. After rectifying the observed nonconformities, periodic CM is done & trend is plotted. If during CM if any fault/ nonconformity/symptom is observed, then Root Cause Symptom Analysis (RCSA) is carried out to find the exact cause of symptom. Corrective Action & Preventive Action is taken to correct the symptom & to avoid it in future. CM continues after CAPA.

The major faults in transformers are Short Circuited Windings, Insufficient Oil Level, Contaminated Oil, Tracking at Insulators, Arcing, corona, Contact Resistances at cable – insulator joints, Choked Breather, etc.

CM of Transformer is done with Thermography, Ultrasound Analysis and Oil Analysis. The Corrective Actions includes, Topping up the Transformer Oil, Filtration of Transformer Oil, Replacement of Windings, Replacement of Bushings, Replacement of Oil, Tightening of Cable – Insulator Joints, Cleaning of Filters, Cleaning of Contact Surfaces, etc.