DANI Transformer Oil Gas Analyzer

Importance of the Topic

The analysis of dissolved gases in transformer oil is a critical preventive maintenance tool for power systems. By identifying specific fault signatures early, operators can avoid catastrophic failures, unplanned outages and reduce the risk of fire or explosion in high-voltage equipment.

Objectives and Overview of the Study

This application note describes the configuration and performance of the DANI Transformer Oil Gas Analyzer (TOGA) for routine dissolved gas analysis (DGA) according to ASTM D3612-C. It demonstrates how the combined DANI Master GC and DANI Headspace sampler deliver reliable quantification of key fault gases in insulating oil.

Methodology and Instrumentation

The method employs headspace extraction of gases from oil samples followed by gas chromatography with dual detection.

• Sample Equilibration: Oil samples equilibrated in a heated headspace vial (100 °C, 30 min).
• Injection: A headspace aliquot (10 mL) is transferred to the GC by automated valve switching.
• Column Configuration: A CarboBOND column separates hydrocarbons and COx, while a molecular sieve 5A column resolves H₂, O₂ and N₂.
• Detectors: Thermal Conductivity Detector (TCD) for permanent gases; Flame Ionization Detector (FID) with methanizer for hydrocarbon and CO₂ analysis.
• Key Conditions: Headspace oven at 100 °C, GC oven ramp from 35 °C to 200 °C at 15 °C/min, carrier gas argon, split ratio 1:1.

Main Results and Discussion

The DANI TOGA system achieved complete baseline separation of eleven diagnostic gases (H₂, O₂, N₂, CH₄, CO, CO₂, C₂H₆, C₂H₄, C₂H₂, C₃H₈, C₃H₆) within a rapid cycle time. Chromatographic reproducibility and linearity were validated using a certified oil standard mixture. The dual-detector approach ensures sensitive detection down to ppm levels and robust quantification across a wide concentration range.

Benefits and Practical Applications of the Method

• Compliance: Fully meets ASTM D3612-C requirements for transformer oil DGA.
• Speed: Fast analysis cycle supports high sample throughput in routine monitoring.
• Reliability: Pretested factory configuration reduces setup time and ensures consistent performance.
• Safety: Early fault detection minimizes the risk of catastrophic transformer failures and associated hazards.

Future Trends and Opportunities

Advances in automated diagnostics and data integration will enhance predictive maintenance. Emerging trends include:

• Real-time DGA monitoring via fiber-optic sensors and on-line analyzers.
• Machine learning algorithms for pattern recognition and fault prediction.
• Miniaturized or portable GC-based systems for field deployment.

Conclusion

The DANI TOGA Analyzer provides a turnkey solution for accurate, rapid and standardized dissolved gas analysis in transformer oil. Its integration of headspace sampling with dual-detector GC ensures high sensitivity and compliance with ASTM D3612-C, supporting proactive transformer condition monitoring.

Reference

ASTM Standard D 3612-02 “Standard Test Method for Analysis of Gases Dissolved in Electrical Insulating Oil by Gas Chromatography, Method C”