- Oil-immersed transformers
- Molded transformers
Changes of Oil-immersed transformers
Recommendation of preventive maintenance
After years of operation, an oil-immersed transformer reaches its end of life. The failure rate of oil-immersed transformers tend to become high after 15 years of operation. Even though the appearance is fairly good, there are possibilities of dangerous conditions.
Benefits of preventive maintenance
- Preventive Maintenance means “preventive action against failure occurrence” and is abbreviated as PM.
It is a particularly important type of maintenance. - This “preventive maintenance” exerts its power effectively during the “wear-out failure period” in the bathtub curve.
What you can expect from PM:
– Accident prevention – Prevention of aging degradation – Extension of life span
Recommended replacement time of parts
Japan Electrical Manufacturers’ Association (JEMA) and Electric Technology Research Association recommend accessories/parts replacement to prolong transformer life. Please study it in conjunction with your plan of transformer inspection.
Accessory name | Recommended replacement time | Requirement of power-off |
---|---|---|
Dial thermometer | Every 10 years | Yes |
Pressure gauge | Every 15 years | Yes |
Oil gauge | Every 15 years | Yes |
Pressure release plate | Every 15 years | Yes |
Bushing | Every 15 years | Yes |
All sorts of gaskets | Every 10 to 15 years | Yes |