The thermal fault of the SF

6

insulating gas chamber of high-voltage electrical equipment can lead to the extraction of CO gas from the insulating material

so the change of CO gas concentration in the SF

6

insulating gas chamber can be used as one of the bases to determine the degree of thermal fault of the insulating gas chamber. In this paper

a method of detecting CO content in SF

6

gas using pyroelectricity principle is studied

and a CO pyroelectricity spectrum s

ensor is designed and developed by this method. The sensor uses a folded optical path with a theoretical detection limit of 1.99 μL/L. The sensor can be used to realize the on-line monitoring of the thermal fault without gas loss in the SF

6

insulating gas chamber of high-voltage electrical equipment

and the sensor can be installed in portable instrument instead of CO electrochemical sensor to overcome cross-interference when using electrochemical sensor to detect co-existence of CO and H

2

compatible gases

and to ensure accurate measurement of CO and H

2

.