Probing the decomposition products of Sulfur hexafluoride (SF6) under partial discharge provides important information for fault diagnosis of Gas Insulated Switchgear (GIS). Here, the effects of discharging time, gas pressure, and discharging voltage on SF6 decomposition products have been investigated by Fourier transform infrared (FTIR) spectroscopy. The infrared spectra of decomposition products such as CF4, SOF2, and SO2F2 have been obtained. It can be found that the CF4, SOF2, and SO2F2 concentrations increase over increased discharging time up to 96 hours. The SO2F2 concentration increases while the discharging voltage is raised from 20 kV to 46 kV, due to the rapid deceleration to the lower energy of electron capture and dissociative attachment. The SO2F2 concentration is reduced while the gas pressure is increased from 0.3 MPa to 0.4 MPa. The present results about the SF6 decomposition can be useful for electrical fault diagnosis.

Hydrogen sulfide (H2S) detection remains a significant concern and the sensitivity, selectivity, and detection limit must be balanced at low temperatures. Herein, we utilized a facile solvothermal method to prepare Cu-doped SnO2/rGO nanocomposites that have emerged as promising candidate materials for H2S sensors. Characterization of the Cu-SnO2/rGO was carried out to determine its surface morphology, chemical composition, and crystal defects. The optimal sensor response for 10 ppm H2S was ~1415.7 at 120 °C, which was over 320 times higher than that seen for pristine SnO2 CQDs (Ra/Rg = 4.4) at 280 °C. Moreover, the sensor material exhibited excellent selectivity, a superior linear working range (R2 = 0.991, 1–150 ppm), a fast response time (31 s to 2 ppm), and ppb-level H2S detection (Ra/Rg = 1.26 to 50 ppb) at 120 °C. In addition, the sensor maintained a high performance even at extremely high humidity (90%) and showed outstanding long-term stability. These superb H2S sensing properties were attributed to catalytic sensitization by the Cu dopant and a synergistic effect of the Cu-SnO2 and rGO, which offered abundant active sites for O2 and H2S absorption and accelerated the transfer of electrons/holes.

A series of new epoxy resin adhesives were prepared by low viscosity bisphenol A epoxy resin E-44 and E-51as the matrix,  low molecular polyamide 650# and phenolic modified JT-3008 as the curing agent, silicon micro powder and calcium carbonate as the fillers. The gelation time, surface drying time and shear strength of the samples were deeply tested. The thermal decomposition temperature and high temperature resistance of the samples were determined by TG analysis. Meanwhile, the surface fracture morphology was observed by SEM. The results showed that a new kind of heat epoxy resin insulation adhesive with long gelation time and convenient construction and meeting the requirements of production adjustment was successfully obtained through the optimization design of the formula,. The new epoxy resin insulation adhesive showed excellent mechanical properties with 18.00 MPa shear strength, which can be used at 380 ℃ for a short period of time and 130 ℃ for a long time.  The new adhesive developed in this paper can be widely used in high voltage switchgear and other insulation materials, which has good application prospects.

This study adopts the FT-IR, DSC, TG and other methods, studied the commonly used in high-voltage switchgear XLPE, EP and organic silicone materials in the same heating rate under thermal degradation properties of three kinds of insulating materials by calculation under different temperature of pyrolysis reaction apparent activation energy E and refers to the former factor to determine its dynamic characteristics. The results showed that the activation energies of epoxy resin, crosslinked polyethylene and silicone rubber were 63.53 kJ·mol-1, 99.66 kJ·mol-1, 62.59 kJ·mol-1, respectively. The pre-exponential factors were 3.2×105·s-1, 4.3×107·s-1 and 1386.9·s-1, respectively.

In this paper, accelerated thermal aging experiment was used to simulate the thermal aging behavior of XLPE, and FT-IR, DSC, TG and other test techniques were used to characterize the materials with different aging periods. The results show that with the aging time, the oxygen-containing groups in XLPE increase, and the crosslinking degree of molecular chains decreases. At the same time, the melting peak of the endothermic peak of the material shifts and the endothermic enthalpy decreases. After aging, the high temperature resistance of XLPE decreases and decomposition occurs more easily. The thermal decomposition of XLPE before and after thermal aging was carried out at different temperatures, and the corresponding thermal decomposition gases were collected. According to GC-MS analysis, the thermal decomposition gas products were all small molecule unsaturated olefin, small molecule containing oxygen and long carbon chain containing oxygen, and the content changed significantly before and after aging.