Sensing of decomposed gas in SF/sub 6/ by using an optical fiber and a corner cube prism deposited with a dye film

An optical remote sensing method for the decomposing reaction of SF/sub 6/ gas caused by an arc discharge is proposed by using an OTDR (Optical Time Domain Reflectometer) system. The corner cube prism is used as a sensor head and its three total reflection planes are coated with a thin film of methyl orange by a vacuum evaporation method. The methyl orange dye is a color reaction reagent for the decomposed gas of SF/sub 6/ such as an HF gas. The arc discharge is carried out in a glass container filled with the SF/sub 6/ gas, and the sensor head connected with the OTDR through the optical fiber is placed in it. The optical sensing system using the OTDR can be applied to monitor and detect some troubles and failures occurring in several gas insulated equipments and their location can be determined.