Oil-immersed Transformers Maintenance Guidelines

Oil-immersed transformers serve as critical components in power transmission and distribution, performing voltage conversion, energy allocation, and system isolation. This article provides an in-depth analysis of oil-immersed transformer  maintenance guidelines, and industrial applications.

1. Maintenance Guidelines

1. Routine Inspections

• Oil level: Should align with 25°C mark (±10%) on conservator gauge

• Oil temperature: Top oil temperature ≤85°C (per GB/T 6451)

• Oil quality:

  • Breakdown voltage ≥35kV/2.5mm (new oil standard)

  • Acid value ≤0.1mg KOH/g

2. Fault Indicators

• DGA anomalies: C₂H₂ >1ppm indicates discharge

• Core ground current: >100mA requires insulation check

3. Maintenance Intervals

2. Industrial Applications

1. Renewable energy:

   • 35kV wind farm substations (IP55 rated)

   • Solar step-up stations (±1500V DC tolerant)

2. Industrial:

   • Arc furnace transformers (200% overload capacity)

   • Rolling mill rectifier transformers

3. Urban grids:

   • Underground substations (with fire suppression)

   • Smart substations (IED integrated)

3. Technology Trends

1. Eco-friendly oils:

   • Natural ester oils (flash point >350°C, biodegradable)

2. Smart features:

   • Embedded fiber-optic temperature sensors (±0.5°C accuracy)

   • AI-powered failure prediction

3. Compact designs:

   • Sealed construction (15-year maintenance-free)

Conclusion

Oil-immersed transformers remain indispensable due to their reliability, cost-efficiency, and proven technology. Selection requires evaluating load profiles, environmental conditions, and efficiency standards (e.g., GB 20052-2020).