Oil-Immersed Transformer Common Failures & Prevention Measures

Oil-Immersed Transformer Problems & Solutions – Expert Prevention Guide

Discover top oil-immersed transformer failures (leaks, overheating, insulation issues) and proven prevention methods. Boost reliability with 2024 maintenance tips!

1. Insulation System Failures (45% of Cases)

Key Problems:

• Transformer oil degradation (acid value >0.1mg KOH/g)
• Moisture contamination (>30ppm)
• Solid insulation carbonization

Prevention:
✅ Oil testing every 6 months (DGA for H₂, C₂H₂ gases)
✅ Use vacuum oil purifiers (keep moisture <15ppm)
✅ Select high-stability oil (KI≥55) for replacements

2. Oil Leakage Issues (25% of Cases)

Common Leak Points:

1. Gasket seals (hardens in 3-5 years)
2. Valve flanges
3. Radiator weld seams

Solutions:
🔧 Install fluororubber gaskets (-40℃~200℃ resistant)
🔧 Use torque wrenches (bolt pressure ≤35N·m)
🔧 UV fluorescent dye testing (detects 0.1mm cracks)

3. Overheating Risks (15% of Cases)

4. Electrical Faults (10% of Cases)

Critical Issues:

• Winding short circuits (partial discharge >10pC)
• Bushing flashover (insufficient creepage)
• Core ground faults (>100mA current)

Prevention:
⚠️ Annual FRA winding tests
⚠️ Silicone composite bushings (anti-pollution)
⚠️ Core ground current monitors

5. Emergency Failures (5% of Cases)

1. False gas relay trips → Install oil flow relays
2. Pressure relief valve sprays → Use dual-piston valves (<70kPa)

Maintenance Gold Standards

Must-Have Tools:

• FLIR T540 thermal camera
• Kelman Transfix oil analyzer
• UE Ultraprobe ultrasonic detecto

3 Key Life-Extension Tips

1. Load Management: Keep 65-80% loading
2. Oil Reconditioning: Add adsorption degassers (2-3x oil life)
3. Corrosion Protection: Apply polyurethane tank coating