Distribution Transformer Maintenance: A Practical Schedule
Distribution transformers are among the most reliable items in an electrical installation, but they are not maintenance-free. A small, disciplined programme dramatically extends service life and catches problems before they become outages.
This article gives a practical schedule for both oil immersed and dry type units.
Distribution transformers are among the most reliable items in an electrical installation, but they are not maintenance-free. A small, disciplined programme dramatically extends service life and catches problems before they become outages.
This article gives a practical schedule for both oil immersed and dry type units.
Routine visual inspection
Check for oil leaks or stains, damaged bushings, corrosion, unusual noise, loose or discoloured connections, blocked cooling air paths and the condition of the enclosure or plant room. Record what you see so trends are visible.
Oil immersed units
Oil level. Check at the gauge or conservator; investigate any drop
Oil testing. Periodic testing for moisture, dielectric strength and dissolved gas analysis
Breather. Check silica gel condition and replace or regenerate when saturated
Protection devices. Verify Buchholz relay, pressure relief device and temperature indicators
Earthing. Check earth connections and bonding
Dry type units
Cleaning. Remove dust from windings and air paths, dust is the main enemy
Insulation. Look for cracks, tracking or discolouration of resin surfaces
Temperature monitoring. Verify sensors, relay settings and alarm/trip function
Fans. Test forced-air fans where fitted
Enclosure. Check IP integrity, filters and ventilation
Condition monitoring
Thermographic surveys under load find hot joints before they fail. Load and temperature logging gives trend data that supports replacement planning.
Records
Keep a simple log: date, readings, observations, actions taken. It is the cheapest insurance you can buy and it materially helps any future failure investigation.
Frequently Asked Questions
Related Products, Applications and Support
Not sure which rating fits your project? Send us your load list and we will size it for you, or email info@xsdfftransformer.com, call +86 158 6789 7761 or WhatsApp +852 5416 2620.