Oil-filled cable surveillance system using newly developed optical fiber gas sensor

A new surveillance system for oil-filled power cables, which can provide continuous monitoring using a newly developed optical gas sensor that can detect the concentration of the gas dissolved in the oil with extremely high sensitivity, has been developed. It was proved that the degree of deterioration of the insulating oil can be detected by measuring C/sub 2/H/sub 2/ and CH/sub 4/ by investigating the relation between the degree of deterioration and amount of combustible gas generated. In order to detect extremely small amounts of gas, a new gas detecting method using the absorption line of the gas using a frequency modulated technique has been developed. The gas detection ability was also confirmed by examination using a 66 kV oil-filled cable and the possibility of detection at an early stage is expected.