Experimental Investigation of Graphene-Coated UHF Sensors for Improvement of PD Detection Sensitivity and Output

While numerous studies on detection improvement of UHF sensors in GIS system have focused mainly on the geometric optimization, the properties of the electrode materials have received comparatively little attention. Therefore, from the perspective of improvement of PD detection sensitivity and output, this study used graphene for coating onto a SS UHF sensor. Surface characteristics were investigated on graphene-coated UHF sensors. Sensitivity comparison tests were conducted based on calibration procedures specified in CIGRE TB 525 and 654, and showed that the graphene-coated SS produced output voltage increases of 8.5% compared to that of bare SS. From the PD simulation test, the graphene-coated UHF sensor exhibited peak output voltage increases of 33.5% and 48.5%, respectively, and both increases were statistically significant in SNR ratio. These results indicate the low resistance and high conductivity of graphene can enhance the measurement sensitivity of UHF band PD signals.