NIR and optical fiber sensor for gases detection produced by transformation oil degradation

In this paper, an innovative optical fiber sensor and near-infrared (NIR) based on reflexion mode were adapted to follow in situ ageing of transformer oil under operation in order to avoid any risk of explosion due to the hydrogen formation. Optical fiber sensor is based on the variation of oil refractive index due to the presence of gases resulting from partial discharges and that may lead to failure of transformer in the long term. We demonstrate that with the use of NIR method we can identify disturbed chemical groups associated with each chemical species created (CH, CC, SiOH, OH, etc.) and detect the formation of methane, ethylene, propane and butane due to partial discharges in transformer oil.