What Is Density in Transformer Oil?
Density is defined as the mass per unit volume (typically expressed in kg/m³ or g/cm³) and is measured at a controlled temperature (usually 15°C or 20°C). Accurate density measurement helps verify oil identity, detect contamination, and ensure compliance with manufacturer specifications and IEC standards.
Test Standard
ASTM D4052 – Standard Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density Meter
Applicable To:
- New transformer oils
- In-service oils (aged or reclaimed)
- Quality control during oil procurement or regeneration
- Verification of oil type and supplier specifications
Key Gases Measured
Insulating Liquids – Measurement of Relative Permittivity, Dissipation Factor (Tan δ) and DC Resistivity.
| Oil Type | Density Range (kg/m³) | Interpretation |
|---|---|---|
| New Mineral Oil | 870 – 895 | Normal, within IEC range |
| > 900 | Possible contamination or degradation | |
| < 860 | May indicate adulteration or wrong oil type |
Why Density Testing Is Important
- Verifies the identity and quality of insulating oil
- Detects contamination (moisture, fuel, or other fluids)
- Identifies mixing of different oil types or improper top-up
- Helps determine oil mass for logistics and inventory management
- Supports condition monitoring and oil acceptance checks
Our Testing Process
- Vacuum-sealed oil sample collected and logged via barcode system
- Testing performed using calibrated digital oscillating U-tube density meter
- Automatic temperature compensation and precision up to ±0.0001 g/cm³
- Real-time ERP integration and trend comparison with historical data
- Results traceable to certified reference materials
Report Includes
- Measured density (kg/m³ or g/cm³) at 20°C
- Relative density (specific gravity)
- Compliance with ASTM/IEC specification ranges
- Flagged deviations and interpretation comments
- Recommendations if out-of-range (e.g., filtration, further testing)
Why Choose Tru-FIL?
- ASTM D4052-compliant testing procedure
- NABL-accredited laboratory with ISO 17025 standards
- ERP-enabled result access with AI-powered interpretation
- Pan-India vacuum bottle collection and 24/7 lab operations
- Trusted by power utilities, EPCs, OEMs, and transformer manufacturers