This article describes various Transformer Oil Types, indicating their distinctive properties and uses. By understanding the types of oil and their regeneration processes, stakeholders can make informed decisions to protect their electrical infrastructure and contribute to sustainable power management practices.
List of Transformer Oil Types
- Paraffinic Mineral Oils
- Naphthenic Mineral Oils
- Silicone Oils
- Natural Esters
- Synthetic Esters
- Synthetic Hydrocarbons
- Bio-based Oils
- High Fire Point (HFP) Oils
- Nanofluids
- Hybrid Oils
- Blended Oils
- Midel Oils
- High-Temperature Hydrocarbon Oils
- Natural Ester-Mineral Oil Blends
It is very important to maintain transformer oil quality as the power grid expands and adapts to new energy challenges. All oils degrade over time, the result of thermal, chemical, and electrical stresses that diminish both insulation and cooling properties. In order to address this critical need, INVEXOIL provides “Transformer Oil Regeneration Systems” that not only restore the properties of aged oils but also ensure compliance with industry-leading standards such as IEC 60296 and IEC 60422. These systems, together with specialized “Transformer Oil Regenerating Services“, demonstrate INVEXOIL’s commitment to enhancing transformer reliability while minimizing environmental impact.
Detailed Explanation of Each Type
1. Paraffinic Mineral Transformer Oils
These are the oils derived from crude oil by refining process. They show good oxidation stability and have a high flash point that makes them suitable for transformer applications with higher temperatures.
Applications: Used in transformer applications where there is a long-term requirement for stability against oxidation.
Table: Paraffinic Mineral Transformer Oils Properties
| Property | Value |
| Density | ~0.86–0.89 g/cm³ |
| Viscosity | 4–150 cSt (at 40°C) |
| Viscosity Index | 90–120 |
| Flash Point | 160–230°C |
| Pour Point | -10 to -25°C |
| Composition | High in paraffinic hydrocarbons (straight and branched chains) |
| Thermal Stability | Moderate |
| Oxidation Stability | High |
2. Naphthenic Mineral Transformer Oils
Naphthenic mineral oils are also derived from crude oil but are of a different chemical structure from paraffinic oils. They have a low pour point and are highly soluble, hence ideal for being used in cold regions.
Applications: Ideal for transformers operating in regions with low temperatures.
Table: Naphthenic Mineral Transformer Oils Properties
| Property | Value |
| Density | ~0.89–0.92 g/cm³ |
| Viscosity | 3–100 cSt (at 40°C) |
| Viscosity Index | 20–80 |
| Flash Point | 150–200°C |
| Pour Point | -20 to -40°C |
| Composition | High in cycloparaffins and aromatic hydrocarbons |
| Thermal Stability | Moderate |
| Oxidation Stability | Moderate |
3. Silicone Transformer Oils
These are synthetic oils with superior thermal and oxidative stability. It has a high flashpoint and finds application in transformer applications where safety and better performance are required.
Applications: Used for transformers that require high temperatures and fire safety.
Table: Silicone Transformer Oils Properties
| Property | Value |
| Density | ~0.95–1.10 g/cm³ |
| Viscosity | 5–100,000 cSt (customizable) |
| Viscosity Index | >300 |
| Flash Point | >300°C |
| Pour Point | -50 to -100°C |
| Composition | Polysiloxane-based with alternating silicon and oxygen atoms |
| Thermal Stability | Very high |
| Oxidation Stability | High |
4. Natural Esters Transformer Oils
Natural esters are derived from vegetable oils and are biodegradable. They have a high fire point and good dielectric strength, making them environmentally friendly alternatives to mineral oils.
Applications: Suitable for transformers in environmentally sensitive areas.
Table: Natural Esters Transformer Oils Properties
| Property | Value |
| Density | ~0.90–0.95 g/cm³ |
| Viscosity | 30–50 cSt (at 40°C) |
| Viscosity Index | ~200 |
| Flash Point | >300°C |
| Pour Point | -10 to -30°C |
| Composition | Triglycerides derived from renewable sources like vegetable oils |
| Thermal Stability | Moderate |
| Oxidation Stability | Moderate |
5. Synthetic Ester Transformer Oils
Synthetic ester derive balance properties between mineral oil and silicones. Its manufacturing processes are by chemical synthesis. They contain properties with high load-carrying capacity thermal and biodegradable.
Applications: Employed in transformers where thermal stability, safety, and environmental performance need to be balanced.
Table: Synthetic Ester Transformer Oils Properties
| Property | Value |
| Density | ~0.90–1.0 g/cm³ |
| Viscosity | Wide range (customizable, typically 10–100 cSt at 40°C) |
| Viscosity Index | 120–180 |
| Flash Point | 200–300°C |
| Pour Point | -40 to -60°C |
| Composition | Chemically engineered esters (monoesters, diesters, polyol esters) |
| Thermal Stability | High |
| Oxidation Stability | High |
6. Synthetic Hydrocarbons Transformer Oils
Synthetic hydrocarbons are engineered oils that offer a balance of properties similar to mineral oils but with enhanced performance characteristics. They are known for their stability and efficiency.
Applications: The most suitable for transformers under severe operating conditions where consistency in performance is highly desired.
Table: Synthetic Hydrocarbons Transformer Oils Properties
| Property | Value |
| Density | ~0.80–0.85 g/cm³ |
| Viscosity | 2–50 cSt (at 40°C) |
| Viscosity Index | 120–160 |
| Flash Point | ~200–300°C |
| Pour Point | -50 to -70°C |
| Composition | Pure hydrocarbon chains (PAOs – polyalphaolefins) |
| Thermal Stability | High |
| Oxidation Stability | High |
7. Bio-based Transformer Oils
These kind of oils are derived from renewable sources such as plants or algae. They are environmentally friendly and biodegradable, offering a sustainable alternative to traditional transformer oils.
Applicarions: Used in transformers where environmental impact is a concern.
Table: Bio-based Transformer Oils Properties
| Property | Value |
| Density | ~0.88–0.92 g/cm³ |
| Viscosity | 30–60 cSt (at 40°C) |
| Viscosity Index | ~180 |
| Flash Point | >300°C |
| Pour Point | -10 to -30°C |
| Composition | Derived from plant-based sources like soy, sunflower, and palm oils |
| Thermal Stability | Moderate |
| Oxidation Stability | Moderate |
8. High Fire Point (HFP) Transformer Oils
HFP oils are specifically designed to have enhanced fire safety properties. They are used in critical applications where fire hazards need to be minimized.
Applications: Suitable for transformers in high-risk environments such as industrial plants and densely populated areas.
Table: High Fire Point (HFP) Transformer Oils Properties
| Property | Value |
| Density | ~0.85–0.95 g/cm³ |
| Viscosity | 20–50 cSt (at 40°C) |
| Viscosity Index | 100–150 |
| Flash Point | >300°C |
| Pour Point | -20 to -40°C |
| Composition | Modified hydrocarbon or ester-based oils |
| Thermal Stability | High |
| Oxidation Stability | High |
9. Nanofluids Transformer Oils
These oils contain nanoparticles, which enhance the thermal conductivity and dielectric properties of the oil. The performance of nanofluids is better than conventional ones.
Applications: Utilized in transformers that need very high efficiency and better cooling.
Table: Nanofluids Transformer Oils Properties
| Property | Value |
| Density | Base oil density + nanomaterial contribution |
| Viscosity | 10–50 cSt (at 40°C), varies with nanoparticle concentration |
| Thermal Conductivity | Higher than base oil (~0.1–1.0 W/m·K, depending on nanoparticles) |
| Flash Point | Dependent on base oil (>200°C typical) |
| Pour Point | Dependent on base oil (-20 to -50°C typical) |
| Composition | Base oil (mineral/synthetic/ester) with dispersed nanoparticles |
| Stability | High (with proper dispersants) |
| Oxidation Stability | Varies with nanomaterial type |
10. Hybrid Transformer Oils
Hybrid oils are a combination of various base oils to get customized properties. They offer the advantages of both mineral and synthetic oils.
Applications: Best for special transformer applications where certain performance characteristics are needed.
Table: Hybrid Transformer Oils Properties
| Property | Value |
| Density | ~0.85–0.95 g/cm³ |
| Viscosity | 10–100 cSt (at 40°C) |
| Viscosity Index | 100–200 |
| Flash Point | >200°C |
| Pour Point | -20 to -40°C |
| Composition | Combination of different base oils (e.g., mineral and synthetic blends) |
| Thermal Stability | Moderate to high |
| Oxidation Stability | Moderate to high |
11. Blended Transformer Oils
These are mixtures of various base stocks or oils with added additives for the enhancement of performance. They provide tailored properties for particular applications.
Applications: They are used in those transformers that require particular performance enhancement.
Table: Blended Transformer Oils Properties
| Property | Value |
| Density | ~0.85–0.92 g/cm³ |
| Viscosity | 5–100 cSt (at 40°C) |
| Viscosity Index | 90–150 |
| Flash Point | ~150–300°C |
| Pour Point | -10 to -50°C |
| Composition | Mixture of mineral, synthetic, or natural ester oils |
| Thermal Stability | Varies (dependent on blend ratio) |
| Oxidation Stability | Moderate |
12. Midel Transformer Oils
Midel oils are synthetic ester-based oils well known for their excellent fire safety and biodegradability. They provide superior performance in high-risk applications.
Applications: Indoor transformers, renewable energy applications, and critical installations that demand high safety standards.
Table: Midel Transformer Oils Properties
| Property | Value |
| Density | ~0.92–0.95 g/cm³ |
| Viscosity | ~20–50 cSt (at 40°C) |
| Viscosity Index | ~180 |
| Flash Point | >300°C |
| Pour Point | -20 to -50°C |
| Composition | Synthetic ester-based fluids |
| Thermal Stability | High |
| Oxidation Stability | High |
13. High-Temperture Hydrocarbon Transformer Oils
These oils are specifically designed to operate at higher temperatures without compromising their dielectric properties. They provide stability and reliability under severe conditions.
Applications: Ideal for transformers operating in high-temperature environments, such as those in industrial plants or desert regions.
Table: High-Temperture Hydrocarbon Oils Properties
| Property | Value |
| Density | ~0.80–0.85 g/cm³ |
| Viscosity | 5–50 cSt (at 40°C) |
| Viscosity Index | >150 |
| Flash Point | >200°C |
| Pour Point | -40 to -60°C |
| Composition | High-purity hydrocarbon chains (polyalphaolefins or other synthetics) |
| Thermal Stability | Very high |
| Oxidation Stability | Very high |
14. Natural Ester-Mineral Transformer Oil Blends
These blends combine natural esters and mineral oils, aiming to take advantage of the environmental benefit of esters with cost effectiveness from mineral oils.
Applications: Suitable for transformers in environmentally sensitive areas where cost considerations are also important.
Table: Natural Ester-Mineral Transformer Oils Properties
| Property | Value |
| Density | ~0.90–0.93 g/cm³ |
| Viscosity | ~20–60 cSt (at 40°C) |
| Viscosity Index | 120–160 |
| Flash Point | >200°C |
| Pour Point | -10 to -30°C |
| Composition | Mixture of natural esters and mineral oils |
| Thermal Stability | Moderate |
| Oxidation Stability | Moderate |
Classification of Transformer Oils Based on Different Aspects
By classifying transformer oils based on these different aspects, we gain a comprehensive understanding of their unique properties, applications, and environmental impacts. This detailed analysis helps in selecting the appropriate transformer oil for specific requirements, ensuring optimal performance and safety. Let’s explore them:
1. Transformer Oil Types Based on Chemical Composition
-
- Mineral Oils
- Paraffinic Mineral Oils
- Naphthenic Mineral Oils
- Synthetic Oils
- Silicone Oils
- Synthetic Esters
- Synthetic Hydrocarbons
- Ester Oils
- Natural Esters
- Synthetic Esters
- Bio-based Oils
- Bio-based Oils
- Other Types
- Nanofluids
- Hybrid Oils
- Blended Oils
- Midel Oils
- High-Temperature Hydrocarbon Oils
- Natural Ester-Mineral Oil Blends
- Mineral Oils
2. Transformer Oil Types Based on Source
-
- Petroleum-Based Oils
- Paraffinic Mineral Oils
- Naphthenic Mineral Oils
- Bio-Based Oils
- Natural Esters
- Bio-based Oils
- Synthetic Oils
- Silicone Oils
- Synthetic Esters
- Synthetic Hydrocarbons
- Petroleum-Based Oils
3. Transformer Oil Types Based on Environmental Impact
-
- Biodegradable Oils
- Natural Esters
- Synthetic Esters
- Bio-based Oils
- Non-Biodegradable Oils
- Paraffinic Mineral Oils
- Naphthenic Mineral Oils
- Silicone Oils
- Synthetic Hydrocarbons
- Biodegradable Oils
4. Transformer Oil Types Based on Performance Characteristics
-
- High Fire Point (HFP) Oils
- Natural Esters
- Silicone Oils
- Low-Temperature Performance Oils
- Naphthenic Mineral Oils
- Synthetic Esters
- High-Temperature Performance Oils
- High-Temperature Hydrocarbon Oils
- Silicone Oils
- Enhanced Dielectric Properties
- Nanofluids
- Blended Oils
- High Fire Point (HFP) Oils
5. Transformer Oil Types Based on Application
-
- General Purpose Oils
- Paraffinic Mineral Oils
- Naphthenic Mineral Oils
- High-Performance and Specialized Oils
- Silicone Oils
- Natural Esters
- Nanofluids
- Midel Oils
- General Purpose Oils
6. Transformer Oil Types Based on Processing and Additives
-
- Pure Oils
- Paraffinic Mineral Oils
- Naphthenic Mineral Oils
- Modified Oils
- Hybrid Oils
- Blended Oils
- Pure Oils
7. Transformer Oil Types Based on Inhibited and Uninhibited
- Inhibited Oils:
- Paraffinic Mineral Oils
- Naphthenic Mineral Oils
- Synthetic Esters
- Synthetic Hydrocarbons
- High Fire Point (HFP) Oils
- High-Temperature Hydrocarbon Oils
- Natural Ester-Mineral Oil Blends
- Uninhibited Oils:
- Silicone Oils
- Natural Esters
- Bio-based Oils
- Nanofluids
- Hybrid Oils
- Blended Oils
- Midel Oils
Conclusion
Understanding the type of transformer oil such as Paraffinic Mineral Oils, Naphthenic Mineral Oils, Silicone Oils, Natural Esters, Synthetic Estersand, and etc. where they are used can facilitate well-informed decisions among stakeholders for maximizing performance and securing the future in constantly changing electrical infrastructure. The innovative INVEXOIL Transformer Oil Regeneration Systems and Transformer Oil Regenerating services based on IEC 60296 and IEC 60422 standards show just how important sustaining the quality of the oil can be to environmental sustainability and operational excellence.
A seasoned economist with a decade of experience in the free market, specializing in macroeconomics, statistical analysis, and business analytics. I am passionate about translating complex economic concepts into actionable strategies that drive success. My track record includes managing sales, developing business strategies, and executing international projects. Proficient in Python and R programming for data-driven decision-making. Committed to leveraging my expertise to enhance economic insights and drive organizational growth.