TOGAS Analysis System with Manual Sampling Nexis GC-2030TOGAS2 GC-2014TOGAS2

Significance of the Topic

Monitoring dissolved gases in transformer oil provides early warnings of insulation degradation and potential failures, supporting preventive maintenance and ensuring transformer reliability.

Objectives and Study Overview

This work describes a streamlined GC method that combines manual sampling with valve switching to analyze key dissolved gases (H2, O2, N2, CH4, CO, CO2, C2H2, C2H4, C2H6) in transformer oil headspace, aiming for rapid, sensitive, and reproducible quantitation under ASTM-D3612C conditions.

Methodology and Instrumentation

• Sampling: Manual injection of headspace vapors into the GC system.
• Valve Switching: Directed flow through three packed columns (P-N, MS-13X, P-Q) to group and separate analytes.
• Detection: Thermal Conductivity Detector for H2, O2, N2; Flame Ionization Detector with methanizer conversion for CO and CO2; FID for hydrocarbons.
• Software: LabSolutions GC workstation controls sequencing and data acquisition.

Results and Discussion

The method achieves baseline separation of permanent gases within 6.5 minutes and hydrocarbons up to C2 within 25 minutes. Detection limits are in the low ppm range (e.g., 2.5 ppm for H2, 50 ppm for O2, N2) and 1 ppm for CH4, CO, CO2, and C2 hydrocarbons. Typical chromatograms demonstrate consistent retention times and clear resolution of all target compounds.

Benefits and Practical Applications

• Single-channel packed column design simplifies maintenance.
• Manual sampling with optional headspace adapter offers versatility for laboratory and field measurements.
• Complete analysis in 16 minutes enhances sample throughput.
• Methanizer unit improves sensitivity for trace CO and CO2 detection.

Future Trends and Potential Applications

Automation of sampling and valve actuation can further increase reproducibility and reduce operator variability. Integration with online monitoring and data analytics platforms may enable continuous condition assessment and predictive maintenance of power transformers.

Conclusion

The presented TOGAS analysis system delivers a robust, efficient, and sensitive approach for dissolved gas quantitation in transformer oil, meeting industry standards and facilitating preventive diagnostics.

References

• ASTM D3612C Standard Test Methods for Qualitative and Quantitative Determination of Gases in Transformer and Insulating Oils by Gas Chromatography