545 / 2022-03-29 16:39:47

Anti-resonant Fiber Enhanced Raman Spectroscopy for Fault Characteristic Gases Dissolved in Transformer Oil

oil-immersed power transformer; fault characteristic gases; Raman spectroscopy; hollow-core anti-resonant fiber

  The detection of characteristic gases dissolved in transformer oil is one of the most effective methods to diagnose the potential faults in oil-immersed power transformers. Raman spectroscopy is suitable for multi-gas detection but intrinsically suffers from low sensitivity. Hence, we established an hollow-core anti-resonant fiber (HC-ARF) based gas Raman sensing platform for transformer-fault characteristic gases (H₂, CO, CO₂, CH₄, C₂H₂, C₂H₄, C₂H₆, SO₂) detection.


  The set-up for platform is shown in Fig. 1. (a) . The laser (λ=532nm, I=1.5W) is collimated by two reflectors. The dichroic mirror reflects the laser to coupler mirror to focus beam into the 30 cm HC-ARF. The Raman signal is filtered by two iris diaphragm before led into spectrometer.

 

  At 3.5 bar pressure and an integration time of 60s, the LOD of H₂, CO, CO₂, CH₄, C₂H₂, C₂H₄, C₂H₆, SO₂ is 25.7, 43, 5.59, 12, 12.5, 14.5, 25, 36.1 μL/L, respectively. In particular, the Raman spectroscopy of acetylene is shown in Fig. 1. (b) .


In this work, we present an fiber-enhanced Raman gas sensing platform for high-sensitivity detection of transformer-fault characteristic gases, which provides a new idea for on-line monitoring and fault diagnosis of transformers.