Overheat diagnosis of power cable based on gas sensors: Device/material exploration

Monitoring the gas composition around power cables using gas sensors is a promising method for detecting their overheating. In this paper we screened the sensing performance in dry and humid conditions of a variety of commercial and homemade sensors. The target gases were 2-Ethylhexanol (2-EH), Dioctyl terephthalate (DOTP), and Benzene; they are the main gases evaporated from overheated polyvinyl chloride (PVC), which is the material of choice for the external insulation of power cables. We found that the tested sensors show different sensing performances to the three target gases, generally with a fast response and slow recovery, the latter especially for 2-EH and DOTP. We also found that the responses to DOTP and 2-EH are correlated and, generally, larger than the ones to benzene. We also showed that by combining the sensors into a sensor array and applying PCA it is possible to distinguish between 2-EH and DOTP, on the one hand, and benzene, on the other hand. However, a more refined pattern recognition method is needed to distinguish between 2-EH and DOTP.