The sensitive characteristics study of SF6 decomposed gases using a graphene sensor

SF₆ filled in gas insulated switchgear (GIS) equipment may decompose in consequence of partial discharge (PD), which is induced by the internal inevitable defects in GIS. Analyzing the SF₆ decomposed components is a good way to diagnose and assess the operating state in GIS. Basically, the various concentration detections of these components, resulted from SF₆ interacting with the micro-water and micro-oxygen which are contained in GIS, are significant to judge the insulation level of SF₆ gas. Chemical gas sensor is an effective way to detect PD. Here in this work, reduced graphene oxide (rGO), a new functional two-dimensional material with a capability of gas sensing is first utilized to detect H₂S, one of SF₆ decomposed gases as well as the important characteristic products under PD according to the existing research achievements. The preparation and test method of rGO sensor are both explained in detail in this paper. Real-time monitoring of relative resistance change through the rGO device is used to confirm the response to SF₆ decomposed gases. Surface morphology is characterized by scanning electron microscopy and Raman spectrum is introduced to estimate the thickness of rGO films. A series of experiments are conducted on the designed experimental system at room temperature in order to approach the real GIS operation condition. Our experimental results demonstrate that rGO layers deposition on epoxy substrate have great potential for SF₆ decomposed components detection. Resistance change rate of H₂S (100 uL/L) reaches 15.78%. Besides, this study discusses the recovery properties, which indicate that the rGO gas sensor is with good repeatability and stability. This study attempts to introduce another new material for SF₆ decomposed components detection.