Mineral Oil or Ester Fluid Filled
3Si Eco Power Design, manufacture and supply a range of mineral oil (ONAN) and fluid filled (KNAN, LNAN) Transformers, both step up and step down. High voltage side from 3.3kV and up to 36kV. Low voltage side from 380V – 433V. We can design and manufacture other specific voltages and ratings if required.
Fluid-filled transformers are electrical devices that use a liquid, usually insulating oil, to cool and insulate the transformer windings. These transformers are commonly used in substations and industrial applications due to their efficiency and reliability. Here are some key features:
Applications
- Power distribution in substations
- Industrial manufacturing facilities
- Renewable energy applications (e.g., wind and solar farms)





Key Features
- Cooling: The fluid absorbs heat generated by the electrical components, maintaining optimal operating temperatures.
- Insulation: The fluid provides electrical insulation between the energized components and the transformer casing.
- Types of Fluids: Commonly used fluids include mineral oil, silicone oil, and, increasingly, biodegradable fluids for environmental safety.
- Design: These transformers often have a sealed tank to prevent moisture ingress and contamination, which can affect performance and longevity.
- Maintenance: Fluid-filled transformers require regular monitoring of the fluid levels and quality, including testing for moisture and acidity.
- Environmental Impact: With a growing focus on sustainability, there’s a trend toward using eco-friendly insulating fluids.
Advantages
- High thermal efficiency
- Enhanced reliability and lifespan
- Lower maintenance costs compared to dry-type transformers
Maintenance
- Routine Inspections: Regular visual checks for leaks, corrosion, and physical damage.
- Fluid Analysis: Testing the insulating oil for dissolved gases, moisture, and contaminants.
- Electrical Testing: Periodic insulation resistance testing and power factor testing.
- Thermal Imaging: Identifying hotspots that may indicate potential failures.