Transformer oil reconditioning and reclamation are essential processes used to restore the insulating and cooling properties of aged or contaminated transformer oil — extending the life of both the oil and the transformer.
Why Restore Transformer Oil?
Over time, transformer oil degrades due to:
-
Oxidation
-
Moisture absorption
-
Contaminants (acids, sludge, carbon)
-
Electrical or thermal stress
If not addressed, degraded oil can lead to:
-
Reduced dielectric strength
-
Insulation breakdown
-
Transformer failure
Oil Reconditioning (On-Site Filtration)
Reconditioning is a physical treatment that removes moisture, dissolved gases, and particles from transformer oil without removing it from the transformer.
Process Includes:
-
Degassing
-
Dehydration (vacuum dehydration)
-
Filtration (micron filters)
Restores:
-
Breakdown Voltage (BDV)
-
Moisture content
-
Clarity & color
Oil Reclamation (Chemical Treatment)
Reclamation goes further — it chemically restores oil properties to like-new condition, typically by removing sludge, acids, and oxidation byproducts.
Process Includes:
-
Fullers earth / activated clay treatment
-
Chemical adsorption
-
Regeneration towers or batch treatment
-
Can be online or offline
Restores:
-
Acidity (neutralization number)
-
Interfacial tension (IFT)
-
Color (removes dark aging)
-
Oxidation stability
Comparison: Reconditioning vs Reclamation
| Feature | Reconditioning | Reclamation |
|---|---|---|
| Removes moisture | ✅ | ✅ |
| Removes particles | ✅ | ✅ |
| Removes sludge/acids | ❌ | ✅ |
| Restores full oil quality | Partial | Near-original |
| Chemical treatment | No | Yes (Fuller’s earth etc.) |
| Duration | Short (hours) | Longer (days) |
Typical Oil Improvements After Treatment
| Property | Before | After Reconditioning | After Reclamation |
|---|---|---|---|
| BDV (kV) | 20–30 | 40–60 | 60+ |
| Moisture (ppm) | 50–100 | <10 | <10 |
| Acidity (mg KOH/g) | 0.3–0.6 | Same | <0.1 |
| IFT (mN/m) | <15 | Slightly improved | >40 |
| Color | Dark brown | Light brown | Pale yellow |
Regulations & Environmental Benefit
-
Reduces hazardous waste generation
-
Avoids full oil replacement costs
-
Meets environmental standards (IEC, IEEE, EPA, ISO 8217)
Recommended Tests Before & After Treatment
| Test | Purpose |
|---|---|
| BDV Test | Measure insulation strength |
| Moisture (Karl Fischer) | Detect water content |
| Acidity Test | Check oil aging level |
| Interfacial Tension (IFT) | Detect oil cleanliness |
| Color & Visual | Evaluate clarity and contamination |
| Dissolved Gas Analysis | Monitor internal faults |