Distribution and power transformers are critical assets with expected lifespans exceeding 30 years. However, poor maintenance can lead to premature insulating breakdown and catastrophic failures. Implementing a predictive maintenance schedule is vital.\n\n### Daily and Monthly Visual Checks\nSimple inspection steps can catch faults early:\n* Silica Gel Breather Inspection: The silica gel should remain blue. If it turns pink, it has absorbed moisture and must be replaced or regenerated to protect the insulation oil.\n* Oil Level and Temperature Gauges: Verify that oil levels correspond to temp markings. High oil temperature indicates overload or radiator clogging.\n* Bushing Checks: Clean bushings to remove contaminants and inspect for oil leaks or hairline cracks.\n\n### Essential Diagnostic Tests\n* Dissolved Gas Analysis (DGA): The most effective diagnostic tool. Sampling transformer oil detects thermal and electrical faults by measuring dissolved gases.\n* Insulation Resistance (Megger Test): Measures the electrical resistance of insulation between winding phases and ground.\n* Oil Breakdown Voltage (BDV) Test: Determines the dielectric strength of the insulation oil. If the BDV value drops below 30kV, the oil must be filtered or replaced.