Distribution Transformer Assessment and Risk Identification in PT PLN (Persero) UID Banten

The distributions transformer is one of the mains equipment for the 20 kV distribution system. Transformer conditions are expected in good condition to prevent unexpected transformer damage. The cause of transformer damage may vary but in PT PLN (Persero) UID Banten transformers damage is mainly due to low insulation resistance and heat due to load unbalance. Low insulation resistance can be caused by the quality of the transformer oil, winding wire insulation quality, and water and salt content. Insulation resistance decreased and overheated can be prevented by conducting a thorough diagnostic by testing the oil and winding insulation resistance. The result from the diagnostic can give information about the transformer reliability index scale. Condition assessment of the distribution transformer includes diagnosis and risk identification. Diagnosis compares transformer condition to transformer standard. The results from the diagnosis are used in risk identification. All information from the assessment creates a clear priority scale for the maintenance timeline of the Distribution Transformer.