Investigation of hypervelocity impact on ceramic fiber insulation tiles: an integrated approach of numerical simulation and experimental validation

Synthetic leakage current data generation for machine learning-Based pollution classification in high voltage insulators

Reviving indigenous electrical insulator manufacturing in sub-saharan Africa: A narrative critical review of barriers and opportunities

Insulator production is a quality-critical manufacturing domain in which small variations in raw-material composition, forming pressure, drying conditions, kiln temperature, and surface finishing can produce latent defects that later affect mechanical strength, dielectric performance, and field reliability. Conventional inspection methods often rely on end-of-line rejection and manual visual checks, which are reactive, labor-intensive, and weak at identifying process drift early enough to prevent scrap. This paper proposes a manufacturing and quality analytics framework for insulator production that integrates statistical process control, machine learning-based defect prediction, and reliability analysis in a single decision-support pipeline. A structured synthetic dataset is used to emulate a porcelain insulator plant, containing process, material, and inspection variables such as SiO₂, Al₂O₃, Fe₂O₃, moisture content, press force, firing temperature, glaze thickness, dimensional deviation, and defect outcome. The methodology combines data preprocessing, feature engineering, process capability analysis, XGBoost classification, and Weibull-based reliability estimation. In the simulated evaluation, the proposed hybrid framework outperforms rule-based quality screening and conventional classifiers, achieving an accuracy of 96.1%, precision of 95.4%, recall of 96.8%, and F1-score of 96.1% for defect prediction. The results indicate that embedding predictive analytics into the manufacturing workflow can reduce non-conforming output, improve process stability, and support risk-aware maintenance and replacement planning. The paper concludes that a unified analytics architecture is more effective than isolated inspection methods for high-volume insulator production and offers a practical foundation for Industry 4.0 deployment in ceramic and electrical insulator plants.

• Undoped sapphire plates has been successfully grown by the micro-pulling down technique from Mo crucibles. • The effect of graphite and alumina ceramics as thermal insulation was compared. • The alumina ceramics allows for a small oxygen pressure in growth chamber and Mo particles are resulting from the degradation of the crucible, which incorporate into the crystal. • Transmission at 532 nm was for the plates grown from Mo crucibles in graphite thermal isolation found to be around 85%. Undoped sapphire plates were grown by the micro-pulling down technique from Mo crucibles, and the use of graphite and alumina ceramics thermal insulation was evaluated . Through the use of these two thermal insulations, the bubbles encapsulated in the plates were analyzed both qualitatively and in terms of their distribution. By comparing with plates grown from Ir crucibles, it is shown that growing sapphire plates from Mo crucibles in graphite thermal insulation results in the best quality, including a more favorable bubble distribution and fewer particle inclusions. It is evaluated that the critical factor is to avoid any source of oxygen in the chamber, as this highly influences the state of the Mo crucible and thereby the sapphire crystals.

ABSTRACT When epoxy resin insulators and bushings in high‐voltage switchgears run in high humidity or significant temperature difference environments, condensation is easy to form on their surfaces, which may lead to a decrease in insulation performance and affect their long‐term operation. Room temperature vulcanized silicone rubber (RTV) coating has good anti‐pollution flashover performance and is widely used on the surface of ceramic or glass insulators to improve their electrical insulation performance. Based on this, RTV coating can be used to improve the electrical properties of epoxy resin in condensation environments, but it still faces the risk of aging failure under the coupling of electric field and humidity. In this paper, the RTV coating method is used to study the electrical characteristics of coatings with different thicknesses (0.3–0.6 mm) during charged aging. The charged aging characteristics of RTV coatings with different thicknesses in condensation environments were analyzed by testing the microstructure, infrared spectrum, dielectric loss and flashover voltage of the samples. The results show that the surface damage of the original sample is the most serious after aging, and a large number of cracks and holes are generated on the surface, while a small amount of particulate matter appears on the surface of the sample coated with RTV coating. With the increase of coating thickness, the static contact angle of the sample surface gradually increases, the aging rate of the RTV coating slows down, and the insulation performance is significantly improved. The electrical performance of the 0.6 mm coating sample is better than that of the thinner coating of 0.3 mm, showing higher surface resistivity and volume resistivity, and has strong resistance to charged aging in the flashover voltage and dielectric loss tests. This study can provide some reference for improving the insulation performance of switchgear in high humidity and condensation environments.

Impact Resistance of Ceramic Fiber Insulation Tiles and Surface Coatings: A Coupled Numerical and Experimental Analysis

Thermal conductivity forward prediction of ceramic fibrous insulation: Combined model based on multiple heat transfer mechanisms considering material design

The trade-off relation between thermal conductivity and fracture toughness limits applications of brittle ceramic thermal insulation materials, and we propose that the high-density dislocation engineering acts as an effective strategy to synergistically reduce thermal conductivity and enhance toughness. The spark plasma sintering (SPS) and heat treatments introduce high-density dislocations (108∼1010 mm-2) into the ferroelastic YTaO4/Y3TaO7 ceramic composites as thermal insulation materials. The effects of high-density dislocations on reducing thermal conductivity and enhancing toughness are elucidated from the phonon relaxation time and crack propagation behaviors, respectively. The high-density dislocations produce large lattice strains to reduce phonon relaxation time, and the lowest thermal conductivity reaches 1.32 W·m-1·K-1. The interfacial enhancements, ferroelastic domains, and high-density dislocations synergistically boost the toughness to 5.0 MPa·m1/2, and the increment is higher than 50%. The effects of high-density dislocations on toughness and thermal conductivity are revealed from an atomic scale, and the proposed high-density dislocation strategy breaks the trade-off relationship between thermal conductivity and toughness for brittle ceramic thermal insulation materials.

Thermal–mechanical coupling analysis of ceramic heat insulation tiles in gas turbine combustion chambers

Room temperature vulcanized silicone rubber (RTV-SiR) is broadly recommended as a high voltage insulator coating (HVIC) for ceramic insulators in polluted zones. However, the rising HVDC ranges impose serious challenges in terms of coating degradation. To increase the acceptability of HVIC, the present work investigates the electrothermal characteristics of RTV-SiR for HVIC using the inclined plane test in conjunction with long-term accelerated aging. Four types of RTV-SiR composites are fabricated by adding various wt% of micro, nano, and micro-nano (hybrid) silica fillers. Inclined plane tests (IPT) are conducted separately for both polarities of DC on pristine and aged samples (treated with accelerated multi-stressing in the lab for 10,000 hours). Unaged hybrid samples (SB4) outperform by achieving the highest initial tracking voltage (ITV) of 3.25 kV for negative polarity DC (–DC) IPT, followed by the counterpart under positive polarity DC (+DC). Similarly, a notable suppression of leakage currents is witnessed in hybrid and 20 wt% silica-added composites throughout the IPT campaign. Also, from time to failure analysis, a relatively shortened time to failure is observed for all blends treated under positive DC, confirming the detrimental impact of positive polarity. For instance, unaged pure SiR samples (SB1) feature 6 hours before failure under –DC stress compared to 5 hours when +DC is applied. From the findings, it is recognizable that hybrid composites depict better overall performance, followed by samples with 20 wt% filler, thus showing high integrity under all test conditions.

Pollution on the surface of an insulator, combined with conditions such as fog, dew, or moisture, directly influences partial discharge (PD) activity, a key indicator of an insulator’s aging process. Using an artificial pollution chamber, three classes of insulators were subjected to saline dew across multiple test runs, during which radiofrequency emissions were recorded by an antenna. The contamination process was monitored and characterized using three indicators derived from the Cumulative Energy per Interval, the Cumulative Average Time Between Signals, and the Cumulative Distributed Energy. By employing segmented regression analysis on these variables, it was possible to detect and quantify changes in PD activity as measured in the ultra-high-frequency (UHF) band by a nearby antenna. Compared with galvanic, leakage-current based approaches and artificial intelligence (AI)-based models, the proposed scheme has lower computational cost and provides operator tunable alert states for training-free, non-contact, trend-based early warning. In every test run, the developed algorithm identified at least one trend change by 80% of the test duration. Analyzing each trend change with the three indicators enabled graded alert states, demonstrating flexibility for assessing flashover (FO) risk. In all experiments conducted on the different types of insulators, FO consistently occurred during the highest alarm state.

High-voltage vacuum bushings are vital for particle accelerators, X-ray tubes, electron microscopes, fusion devices, and electron sources. Commercial bushings, however, are limited to ~ 100 kV, and exceeding this limit has proven to be difficult. This work reports the physics-informed design, simulation, and experimental validation of Hammerhead, a compact vacuum bushing that has been tested up to 330 kV and used reliably at 300 kV. The design utilizes a coaxial electrode configuration and a ceramic insulator that bridges the gap using a flashover-resistant geometry. Compared with the state-of-the-art, Hammerhead nearly doubles the voltage holdoff per unit of volume, does not require ultra-high vacuum conditions or sub-micron polishing, and can be manufactured in a moderate cleanroom environment. It also integrates directly with a high-voltage coaxial cable, without the need for insulating fluids or pressurized gas. Here, it is shown - over 144 h of experimental testing - that Hammerhead operates stably at 300 kV with dark current below 10 μA.

With the development of electronic guns toward high voltage, large capacity, and miniaturization, the surface flashover of ceramic insulators has become a key problem that leads to insulation damage, limits equipment performance, and reduces system reliability. In this paper, surface flashover experiments were conducted on irregular ceramic insulator, and the phenomenon of surface flashover discharge was observed on the double-sided surface. It was found that the inner surface of the ceramic insulators with this structure is more prone to flashover discharge by application of optical diagnostics, indicating that the weak point of insulation is the inner surface of the insulator. Through simulations of the electric field distribution and flashover discharge processes on insulator surfaces, three critical factors are identified to significantly influence flashover development: the enhanced electric field at the cathode triple junction, the strong normal component of the surface electric field, and the groove structures. The inner surface exhibits stronger field intensification at the cathode triple junction, generating more primary electrons. Concurrently, the parallel electric field components near the cathode triple junction promote the emission of secondary electrons. In contrast, the outer surface's groove configuration suppresses discharge by altering electron trajectories. These combined effects make the inner surface more vulnerable to flashover occurrence. The research in this article has important scientific and engineering significance for the safe and stable operation of electronic guns and the improvement of technical level.

The use of sustainable industrial waste composites in reinforced concrete structural applications will be eco-friendly. The aim of the present study is to evaluate the regression-based flexural response of reinforced concrete beams by using ceramic electrical insulator waste as a substitute for cement and aggregate. The assessment of flexural behavior is presented in this study from bending stress, deflection, and crack width measurements. It details an experimental program suitably designed and tested to evaluate the responses of reinforced insulator concrete beams (flexure, shear and bond types) and generate the regression modeling. The results indicate that, in comparison to the reference beams (M1 F, M1 B, and M1 S), the bending stress of flexure- (M4 F), bond- (M4 B), and shear-reinforced (M4 S) insulator concrete beams increased by 17.41%, 13.52%, and 27.77%, respectively. The deflection values of flexure- (M4 F), bond- (M4 B), and shear-reinforced (M4 S) insulator concrete beams decreased by 10%, 8%, and 17%, respectively, compared to the reference beams. Similarly, the crack width of flexure- (M4 F), bond- (M4 B), and shear-reinforced (M4 S) insulator concrete beams decreased by 35%, 34.72%, and 35.07%, respectively, compared to the reference beams. The difference between regression and experimentally predicted results showed less than 4% error. The regression- predicted that R 2 values were more than 97%. The regression correlation reveals that there exists a close relationship among bending stress, deflection, and crack width in the first crack stage, service stage, yield stage, and ultimate stage. The sustainability factors obtained, such as energy consumption (E c = 3521.78 MJ/m 3 ), CO 2 emission reduction (CO 2 e = 781.37 kg/m 3 ), and cost benefit of 24.41%, were benefits of the study. Overall, the experimental findings aligned well with regression prediction and also demonstrate that insulator waste can be utilized to produce sustainable and cost-effective reinforced concrete without compromising structural performance.

Abstract The study aims at the utilization of ceramic insulator manufacturing industry waste in standard strength concrete (SSC) for infrastructural applications which addresses the Sustainable Development Goal (SDG‐11). The ceramic waste powder (CWP) from the electrical insulator industry has been used in the present study. From the x‐ray fluorescence analysis, it was found that the ceramic electrical insulator waste powder shows a significant increase in pozzolanic chemical composition. As many studies have been done on the mechanical and durability properties of concrete using CWP, the focus on the torsion resistance of ceramic waste reinforced standard strength concrete (RSSC) beams has not been thoroughly examined. In this study, six beams of 1.50 m span were cast and tested using the Materials Testing System loading frame. The ultimate torsional moment, angle of twist, torsional stiffness, curvature ductility and fracture width of each beam specimen were evaluated and compared. The experimentally found ultimate torque was compared theoretically using a space truss analogy and IS 456‐2000. The average increase in ultimate torsional moment and curvature ductility of ceramic waste RSSC beams was found to be 23.35% and 4.50%, respectively, when compared with the control RSSC.

External wall insulation composite systems (ETICS) play a crucial role in enhancing building energy efficiency, with glazed foam ceramic insulation boards (GFCIBs) emerging as a particularly promising material. Despite their growing application, there remains a notable research gap regarding the mechanical performance of ETICS incorporating GFCIBs. This study comprehensively investigates the mechanical characteristics of ETICS through a series of standardized tests, including compression, three-point bending, uniaxial tensile, Brazilian disk, single shear, and oblique shear analyses. The experimental results demonstrate that GFCIBs exhibit exceptional mechanical properties, with a tensile strength of 1.26 MPa, compressive strength of 10.4 MPa, bond tensile strength of 0.85 MPa, bond shear strength of 0.23 MPa, tensile modulus of elasticity of 4.4 MPa, and compressive modulus of elasticity of 628.6 MPa. Further, the material displays significant dual-modulus characteristics. The study also presents a modified formula for calculating tensile and compressive strength in three-point bending tests, with preliminary validation of its feasibility. These findings not only provide essential experimental data for ETICS design and material selection but also offer novel methodological insights for evaluating the bond strength of similar composite materials.

Failures in ceramic insulators, primarily due to contamination flashovers and punctures, result in significant technical and economic losses. Early detection of these defects is crucial to prevent catastrophic outcomes. Insulator strings often exhibit multiple co-occurring defects, generating various discharge activities such as partial discharge, corona, and dry band arcing, each emitting ultrasonic signals. The overlap of these signals poses challenges for accurate diagnosis. This study develops a multi-label classification model to diagnose insulators with both single and multiple defects. Analysis of the acoustic signals for each defect identified unique temporal features, enabling precise characterization based on sound signatures.

Ceramic insulators may experience a decrease in internal insulation performance and become zero value insulators due to environmental factors after being put into operation. Regular zero value testing is required to identify zero value insulators. The impulse high voltage method is one of the effective methods for zero value detection, but existing impulse high voltage methods only focus on the voltage response characteristics of insulators under impulse high voltage, without paying attention to the current response characteristics. This study proposes a zero value detection method based on the current response characteristics under impulse high voltage. The response current is converted into an induced voltage signal through a magnetic ring inductor, and the difference between zero value and the peak induced voltage of a normal insulator is used to achieve reliable identification of zero value. In the case of insulator surface contamination, this method is more robust and has a lower risk of misjudgment compared to detection methods based on voltage response characteristics. The research provides new ideas for insulation testing of ceramic insulators, which helps to improve the reliability of the power grid. Further exploration is needed in the future to determine the reasons for the reliability differences between the two methods.

This project describes the development of an industrial electric furnace with dimensions of 3000 x 600 x 500 mm, specifically designed for the heat treatment of SA-178 Gr A steel tubes. The main objective is to ensure microstructural uniformity and stress relief, crucial factors for optimizing mechanical properties like ductility and toughness, thereby preventing failures. The furnace is constructed with ASTM A36 steel plates and features 150 mm of ceramic fiber blanket insulation. The heating system, composed of 220 V electrical resistances, operates at a temperature of 800 °C, considering an ambient temperature of 35 °C. The project was developed in compliance with NR-10 and NR-12 standards. The results confirm the technical feasibility of the proposed solution and its potential for industrial application.