Basalt fiber (BF) has a high mechanical strength, excellent temperature resistance, good chemical stability, low energy consumption, and an environmentally friendly production process. In addition, BF-reinforced polymers (BFRPs) have good corrosion resistance and designability; thus, they meet the application requirements of electrical equipment, such as new conductors, insulating pull rods, and composite cross-arms. However, there are still a series of technical issues in the mass production of BF, and the stability of the products needs to be further improved. Therefore, the research on the production, modification, and application of BF is necessary. This paper discusses the chemical composition and production technology of BF, describes the morphology and properties of BF, summarizes the interface problems and modification methods of composites, and finally, introduces the application prospects of BF in the field of electrical materials, which is expected to provide a reference for the application and promotion of BFRP in the future.

Basalt fibre composite materials have shown good application prospects in electrical equipment, but their reliability can be affected by damp‐heat ageing. In this work, the interface, mechanical, and electrical properties of basalt fibre composites treated with three coupling agents via damp‐heat ageing were compared. Molecular simulations were conducted to reveal the damp‐heat ageing mechanism of the composites. The results show that γ ‐aminopropyl triethoxy silane (KH‐550) and γ ‐glycidoxy propyl trimethoxy silane (KH‐560) perform better as coupling agents as they form bonds with the matrix resin, compared with γ ‐methacryloxy propyl trimethoxy silane (KH‐570). After the damp‐heat ageing treatment, the hydrolysis of the defects of the amino groups in the interface of the KH‐550‐treated sample can weaken its mechanical properties and insulation properties greatly. The interface layer of the KH‐560‐treated sample is mostly composed of carbon–oxygen single bonds and methylene groups with its interface structure more stable, which endows the sample with better stability of its mechanical and insulating properties. Therefore, KH‐560 is a more suitable coupling agent for processing basalt fibres to be used in electrical equipment.

Real-time and accurate supervision of contamination conditions of composite insulators can effectively prevent the occurrence of pollution flashover accidents and ensure stable operation of the power system. In this article, a refined and controllable artificial contamination experiment is carried out, in which a total of 60 types of pollutants (12 contamination conditions) are formed by combining 20 types of equivalent salt deposit densities (ESDDs) at four contamination levels and three types nonsoluble deposit densities (NSDDs)/ESDD ratios to pollute composite insulators. Hyperspectral imaging technology is also introduced to extract the spectral data of polluted insulators, and the changing pattern of spectral curves under different pollution conditions is studied. Then, the spectral curve is preprocessed by black-and-white correction, standard normal variate (SNV), and detrending correction, and the preprocessed data are analyzed for band correlation. According to the variation pattern of the spectral curve and the band correlation characteristics, the full set of bands is divided into red, other visible, and near-infrared regions for principal component transformation respectively. Compared with the traditional principal component transformation, the former can reduce the calculation amount by 66%. Finally, to solve the problem of insufficiently labeled samples in practical engineering, a semi-supervised ladder network is used to realize pixel-level evaluation of insulator contamination conditions, and evaluation results are visualized. Research results show the pixel-level evaluation method can accurately evaluate contamination conditions of different areas on the surface of composite insulators. A semi-supervised model can guarantee the accuracy of classification results when there are few labeled samples. When the supervision rate is 10%, the classification accuracy of a semi-supervised model for contamination grade, NSDD/ESDD ratio, and contamination condition is higher than 95%, while that of a supervised model is lower than 90%.

Traditional monitoring methods cannot obtain the overall thermal information for power transformers. To solve this problem, a distributed fiber optic sensor (DFOS) was creatively applied inside an operating 35 kV power transformer by highly integrating with the electromagnetic wires. Then, the transformer prototype with totally global sensing capability was successfully developed and it was qualified for power grid application through the strict ex-factory tests. The as designed optical fiber sensor works stably all the time with a temperature accuracy of ±0.2 °C and spatial positioning accuracy of 0.8 m. Based on the obtained internal temperature distribution, Gaussian convolution was further applied for the signal processing and hereby, the hotspots for all the windings and iron cores could be accurately traced. The hottest points were located at 89.1% (55 °C) of the high voltage winding height and 89.7% (77.5 °C) of the low voltage winding height. The actual precise hotspot location corrected the traditional cognition on the transformer windings and it would serve as an essential reference for the manufactures. This new nondestructive internal sensing and condition monitoring method also exhibits a promising future for the DFOS applying in the high-voltage electrical apparatus industry.

Transformer plays a vital role in grids and its internal hot-spot temperature is a crucial monitoring parameter. In this paper, three groups of temperature rise tests with the load rate of 70%, 100%, and 125% were carried out on a 110 kV transformer with built-in distributed sensing fiber. Based on the distributed temperature sensing technology, the temperature distribution of winding was acquired. Accuracy of IEC, Susa, and Swift thermal models was compared. To eliminate the non-negligible error in cooling process, a modified-Susa model based on driving factor and steady-state temperature rise was proposed. Using this, the top oil temperature prediction error during operation and cooling is reduced. In addition, the real-time tracking of hot spots and analysis of overall temperature gradient of windings was implemented. The accuracy of different hot spot calculation models was also compared. Results show that the prediction accuracy of each model is satisfactory during the operation, but the error during the cooling process cannot be ignored. The refined temperature distribution of the winding was also obtained by the high-resolution Brillouin optical time-domain analysis sensing method. Periodic temperature fluctuations and local hot spots inside windings are perceived, which is confirmed to be closely related to winding geometry.

Due to long-term exposure to high electrical field strength, heavy loads, and the complex climatic conditions in tropical coastal areas of China, widespread abnormal heating phenomena often occur in the operation of composite insulators in power transmission lines, posing a threat to the safe and stable operation of the power system. To study the ageing process of the silicone rubber sheath of composite insulators in the high-field, high-humidity, high-temperature, and high-salt-density environments along the coastal regions, this paper establishes a humidity–heat–electricity–salt spray accelerated ageing test platform and conducts ageing tests on silicone rubber materials for composite insulators under the coupled effect of multiple factors. The ageing characteristics of silicone rubber materials are analyzed using scanning electron microscopy, Fourier infrared spectroscopy, thermogravimetric analysis, and other methods. The results show that the coupled ageing factors have an impact on the surface morphology of silicone rubber. The continuous depolymerization of PDMS molecular chains leads to a decrease in the content of groups related to the hydrophobicity of the material, resulting in a deterioration of its hydrophobicity. Moreover, the degradation of silicone rubber materials and the enhanced moisture absorption capacity lead to an increase in the dielectric loss tangent of the saturated moisture-absorbing medium, thereby causing abnormal heating of the sheath at the end of the composite insulator. The research findings of this study are of significant reference value for revealing the degradation mechanism of composite insulator silicone rubber sheaths in tropical island environments and improving the service life of composite insulators.