From serving the basic role of cooling and insulation to contributing to green power generation, transformer oil has come a long way. With international demand experiencing substantial growth, the product holds an interesting story. It has evolved from a simple mineral oil to a synthetic one, followed by further incorporation with nanotechnology. Innovations haven’t stopped here but have transcended the quality by influencing a variety of factors. Know all of it and more right here as we explore the basics, past and current status, which type of oil is used in transformers, and much more.
What is Transformer Oil?
Let’s begin with understanding what is transformer oil. The transformer oil is also referred to as insulating oil. It is derived from crude petroleum with characteristics of mineral insulation or cooling with low flammability. It means that the oil dissipates the heat and provides liquid insulation.
The transformer oil finds applications in electrical equipment like capacitors, oil-filled transformers and others to act as a coolant and prevent oxidation. The industries or companies dealing with power generation, transmission and distribution generally use oil for its properties. Further, transformer manufacturers and repairers also hold the largest market share.
Types of Transformer Oil
There are two types of transformer oil: mineral and synthetic. Now, among these, what oil is used in the transformer? Know this by understanding their properties.
Mineral Oil
Mineral oil is commonly used due to its excellent insulating properties and cost-effectiveness. It is further classified into two categories: naphtha and paraffin-based oil.
- The naphthenic mineral oil is preferred for high solubility and stability. It has a low pour point that allows efficient usage in areas with low temperatures. One downside of the naphthenic oil is the formation of more sludge compared to its counterpart, paraffin-based oil.
- Paraffinic mineral oil possesses a high pour point and is better at oxidation prevention. The oil has a high boiling point and a low evaporation rate, making it well-suited for areas with warm temperatures. It is less soluble than naphthenic oil.
Synthetic Oil
As evident by the name, this type of transformer oil is synthesised through chemical processes. Hence, it is preferred by those seeking excellent quality properties for the functions. However, these are costly compared to mineral oil. Synthetic oils are of multiple types, the major ones being silicone and ester-based oils.
- Silicone oil is utilised for top-notch electrical insulation and thermal stability. Further, its oxidation and fire resistance enhance its applications in high-risk environments.
- Ester oil also exhibits excellent insulation and cooling properties and is biodegradable. They also possess fire resistance properties.
Testing of Transformer Oil
There are a variety of tests to check the quality of transformer oil. These include:
Dielectric Strength Test
It is also referred to as the Breakdown Voltage (BDV) Test, which measures the insulation properties of the transformer oil. It evaluates the ability to withstand electrical stress, which further indicates the oil’s capability to prevent electrical breakdown and short circuits.
Acid Number Test
This test assesses the oil for the amount of acidity. It marks the oil’s level of oxidation and degradation. The oxidation leads to sludge build-up, thus negatively impacting the quality and efficiency.
Interfacial Tension Test
This test helps to identify the presence of contaminants impacting the quality of the oil. It detects the polar components and oxidation byproducts by measuring the tension at the interface between oil and water.
Colour Test
The oil is evaluated based on the colour. It works as aged oil with low efficiency exhibits the transformer oil colour change to darker shades. On the other hand, fresh transformer oil has light shades of colour, such as yellow, orange, or red.
Water Test
The presence of water compromises the insulating properties of oil and speeds up the aging of insulating materials. It also leads to transformer failure and poses safety risks.
Flash Point Test
It determines the possibility of fire hazards with the oil during its usage. The flash point test checks the lowest temperature at which the oil’s vapours can ignite on flame exposure.
Pour Point Test
It assesses the lowest temperature at which the oil remains flowing under standard conditions. It helps understand the suitability of transformer oil for regions with low temperatures.
Benefits of Choosing the Application-Specific Transformer Oil
The right transformer oil helps fulfil the reason why oil is used in a transformer. The advantages of accurate choice as per the features are as follows:
- The high thermal conductivity of the oil enhances heat dissipation, which subsequently improves the life of equipment and devices.
- The compatibility with other materials of the transformer is designed to prevent cross-reaction and degradation.
- The high-quality insulation prevents electrical breakdown and also improves the overall insulation performance.
- The high oxidation stability minimises sludge formation and enhances the life of the oil
- Good ageing characteristics further ensure the retention of the properties after a long duration of usage
While the well-thought-out decision-making in the quality of transformer oil is important, there is another aspect to focus on. It is the choice of the brand. Here is how choosing the top brand influences the product to be received:
- Oil will comply with national and international standards and benchmarks.
- Allows for obtaining customised grade oil
- Developed by an indigenous R&D team and quality manufacturers to serve the global audience
- Comprises excellent properties
- Passed the 2006 Oil/Copper interactions tests as described in ASTM D 1275B
Segmentation and Expansion of the Transformer Oil Market
As per the Industry Arc report on the transformer oil market forecast for 2025 to 2031, the market is estimated to reach $3,920 million by 2030. This is expected as per the CAGR of 7.90% expected during the period 2024 to 2030. The dominant region in the transformer oil market is the Asia Pacific region, the reason being attributed to the investment and development of power generation industries.
The demand for green power generation and damage protection to electrical equipment are the key driving factors for growth. Besides these, the modernisation of electric grids and the adoption of smart grids in developed countries are also contributing factors. Opportunities that hold further potential for market growth include increased investment in HVDC transmission systems.
Recent Innovations and Explorations in Transformer Oil
The different innovations and scientific advancements have enhanced the quality and characteristics of transformer oil. Here is an insight into the same:
- Nanotechnology-enhanced smart oils have been developed with improved insulation and cooling, along with the presence of high thermal conductivity.
- Self-healing oils come along with automatic antioxidant release and microcapsule-triggered defence.
- AI-compatible oils possess embedded sensors for real-time monitoring.
- Antiviral oils exhibit bio-inhibition, thus making them contamination resistant, and more innovations have been done
Considering the products, the recent developments include:
- Circular transformer oil exhibiting enhanced resource efficiency in the electrical industry
- Eco-friendly ester transformer fluids
- Oil with improved properties and lower gassing tendencies
Conclusion
Transformer oils play a pivotal role in power generation and other industries. Being a key component, their properties influence the life of devices and equipment. The transformer oil market is expected to witness a CAGR of 7.90%. With the high importance of the product and the blooming market, the product is experiencing scientific innovations and development as well.
From enhanced quality of both mineral and synthetic oil to AI integration, it has evolved a lot. Further evolution with scientific advancements is certain to outperform the existing limitations while seizing the opportunities. Hence, transformer oil will remain a key component in ensuring safe, efficient and future electrical infrastructure. Looking for quality transformer oil manufactured as per your needs? Connect with us to know how we can fulfill your specific demands.