Nano-tin oxide gas sensor detection characteristic for hydrocarbon gases dissolved in transformer oil

Methane, ethane, ethylene, acetylene are the effective failure characteristic gases for power transformer. Semiconductor metal oxide gas sensor based on tin oxide had been well applied in on-line monitoring of dissolved gas in transformer oil. Nano-SnO2 power was prepared by the sol-gel method in this paper. The microstructure and morphology o f the prepared gas sensitive materials were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. Nano-SnO2 based semiconductor gas sensors were fabricated by an indirect heating process, and the gas sensing properties were tested for the dissolved hydrocarbon fault gases methane, ethane, ethylene and acetylene. Test results show that gas sensors exhibit good sensitivity, repeatability, stability and linearity for methane, ethane, ethylene, acetylene. The result of theoretical calculation shows that difference in orbital energy of gas molecular is a qualitative factor for gas sensing sensitivity at different operating temperatures.