On-Line Transformer Gas Analyzer represents a new generation of test equipment for analysis the dissolved gas in oil. HZ-101S adopted the advanced infrared photo-acoustic spectroscopy technology and the friendly operation interface. The concentration data of the 8 key fault gases and moisture can be drawn directly within 15 minutes in the field. It really can take place of the Gas Chromatography system in the laboratory because of the accurate, rapid, reliable results. Thus the HZ-101S is one of the best tools for the electric equipment asset evaluation.