Tracking Resistance Research Articles

Long-term aging characteristics of co-filled nano-silica and micro-ATH in HTV silicone rubber composite insulators

Multiple environmental stresses produce complex phenomena of aging in polymeric insulators. The main aim of this research is to investigate the improved aging characteristics of silica (SiO2)/alumina trihydrate (ATH) hybrid samples (HSs) in high-temperature vulcanized rubber. For this purpose, three HSs comprising 20% micro-ATH with 2% nano-SiO2 (S2), 4% nano-SiO2 (S4), 6% nano-SiO2 (S6) along with sample-virgin (SV) are subjected to long-term accelerated aging of 9000 h. A special aging chamber is fabricated for the aging process of samples. The aging characteristics of these samples are investigated by measuring leakage current (LC) and hydrophobicity classification (HC) after every weathering cycle. Similarly, Fourier transform infrared (FTIR) spectroscopy is performed to observe the important structural changes over the entire aging time. The dielectric strength of AC is also performed after every 1000 h of aging. Tracking and erosion resistance and mechanical properties are also investigated before and after aging. From the critical investigation, it is observed that HSs possess improved results in all the conducted tests. S2 has the lowest LC and HC values throughout the aging time. Similarly, S6 described the highest breakdown strength at the end of the accelerated aging. In the case of FTIR, it is analyzed that the important wave numbers remain intact for all the HSs in the accelerated aging environment. The loss percentage in the wave number for SV is higher, compared to the HSs. After performing the tracking and erosion resistance test, HSs have superior performance. For some of the mechanical properties, HSs showed improved values. Thus, from the experimental analysis, it is deducted that the sample S2 offers the highest resistance to the aging conditions, compared to the SV and other HSs.

Synergistic enhancement of vinyltriethoxysilane and layered Mg–Al double hydroxide on the tracking and erosion resistance of silicone rubber

It is of great significance and challenge to efficiently improve the tracking and erosion resistance of silicone rubber along with the growing requirements in the field of outdoor high voltage insulation. In this work, we herein proposed an effective way to address this issue by incorporating vinyltriethoxysilane (ViTES) and layered Mg–Al double hydroxide (LDH) into high temperature vulcanized silicone rubber (HTVSR). ViTES/LDH notably enhanced the tracking and erosion resistance of HTVSR. With addition of 3.33 phr ViTES and 5.00 phr LDH, the anti-tracking performance of HTVSR reached the 1A 4.5 level, and the eroded mass was merely 0.3%. The results of scanning electron microscopy and equilibrium swelling showed that ViTES substantially improved the interfacial interaction between HTVSR and LDH and the crosslinking density of HTVSR, and enhanced the dispersion of LDH sheets in the HTVSR matrix. The possible synergistic suppression mechanism of ViTES/LDH on the tracking and erosion of HTVSR was further studied and demonstrated by the plasma irradiation analysis, thermogravimetry and thermogravimetry-Fourier transform infrared spectrometry. It was indicated that under the high voltage arcing discharge, LDH facilitated the formation of a dense barrier layer consisting of bimetal mixed oxides on the HTVSR surface, exerting outstanding lamellar barrier effect. The further degradation and the generation as well as development of electrical tracking were efficiently suppressed. Our findings provided a new approach to fabricate silicone rubber with excellent tracking and erosion resistance.

Catchment-scale export of antibiotic resistance genes and bacteria from an agricultural watershed in central Iowa.

Antibiotics are administered to livestock in animal feeding operations (AFOs) for the control, prevention, and treatment of disease. Manure from antibiotic treated livestock contains unmetabolized antibiotics that provide selective pressure on bacteria, facilitating the expression of anti-microbial resistance (AMR). Manure application on row crops is an agronomic practice used by growers to meet crop nutrient needs; however, it can be a source of AMR to the soil and water environment. This study in central Iowa aims to directly compare AMR indicators in outlet runoff from two adjacent (221 to 229 ha) manured and non-manured catchments (manure comparison), and among three catchments (600 to 804 ha) with manure influence, no known manure application (control), and urban influences (mixed land use comparison). Monitored AMR indicators included antibiotic resistance genes (ARGs) ermB, ermF (macrolide), tetA, tetM, tetO, tetW (tetracycline), sul1, sul2 (sulfonamide), aadA2 (aminoglycoside), vgaA, and vgaB (pleuromutilin), and tylosin and tetracycline resistant enterococci bacteria. Results of the manure comparison showed significantly higher (p<0.05) tetracycline and tylosin resistant bacteria from the catchment with manure application in 2017, but no differences in 2018, possibly due to changes in antibiotic use resulting from the Veterinary Feed Directive. Moreover, the ARG analysis indicated a larger diversity of ARGs at the manure amended catchment. The mixed land use comparison showed the manure amended catchment had significantly higher (p<0.05) tetracycline resistant bacteria in 2017 and significantly higher tylosin resistant bacteria in 2017 and 2018 than the urban influenced catchment. The urban influenced catchment had significantly higher ermB concentrations in both sampling years, however the manure applied catchment runoff consisted of higher relative abundance of total ARGs. Additionally, both catchments showed higher AMR indicators compared to the control catchment. This study identifies four ARGs that might be specific to AMR as a result of agricultural sources (tetM, tetW, sul1, sul2) and optimal for use in watershed scale monitoring studies for tracking resistance in the environment.

Field investigation on the lateral resistance of railway tracks with frictional sleepers

Tie type is one of the most effective parameters for changing the lateral resistance of ballasted track. In this study, the lateral resistance of an existing curve-to-lateral movement is investigated in the field in two conditions: with simple mono-block concrete ties (B70) and with friction concrete ties (B70F). After that, lateral resistance is measured through the panel displacement method. The results show that the lateral resistance of the railway track increases by approximately 67% with the use of friction concrete ties (B70F) instead of standard mono-block concrete ties (B70).

Effect of regular and core shell nano fillers on the partial discharge and tracking performance of low density polyethylene

Solid insulation materials are the backbone for all kinds of outdoor insulation applications. Environmental stresses degrade every outdoor insulation material with the passage of time. Internal partial discharges and external surface tracking are the two major factors governing the health of outdoor insulation. Best outdoor insulation is the one having lowest level of partial discharge and highest resistance to tracking. Improvement in tracking resistance of polymeric insulation materials has been a concern of many researchers. This study investigates the improvement in partial discharge and tracking resistance of LDPE under the effect of three different nano fillers including SiO2, TiO2, TiO2@SiO2. A very little has been reported on the effect of these nano fillers on the tracking performance of LDPE. TiO2@SiO2 is a novel core–shell nano filler. No study has reported the effect of these core–shell nano fillers on the partial discharge and tracking performance of LDPE. It has been observed in this study that core–shell nano fillers are much more efficient in improving partial discharge and tracking resistance of solid insulation materials than ordinary nano fillers.

Performance analysis of silicone rubber insulator in DC high-voltage inclined plane tracking test

The present trend in electric power transmission technology evolves with the latest high-voltage direct current (HVDC) transmission network. Silicone rubber (SiR) composite insulators are predominantly used since two decades for high-voltage alternating current (HVAC) transmission lines. In case of HVAC transmission line, the performance of SiR insulators is promising; however, there are failures reported with their uses for HVDC transmission line. In this research work, SiR composite formulations are varied to study their effective changes in the direct current (DC) tracking and erosion resistance. Four different weight percentage (wt%) aluminum trihydrate (ATH) fillers loaded SiR formulations are prepared and invariably subjected to positive polarity DC inclined plane tracking (DCIPT) test before and after ultraviolet (UV) aging. The Fourier transform infrared spectroscopy study has been carried out to understand their morphological changes after and before UV aging. The results of these tests indicated that DC tracking and erosion resistance effectively reduced severe surface degradation for UV-aged SiR material. However, the 40 wt% ATH-filled SiR sample performed well exhibiting higher time to failure in positive DCIPT and thus could be better usable as HVDC insulation material.

이종 필러 추가에 따른 에폭시 마이크로 복합체의 절연성능 연구

In this paper, essential properties that affect electrical insulation performance of epoxy micro composites were studied. In particular, the effect of adding co-filled micro sized fillers to epoxy composites were explored. The fillers considered in this study include 40 [um] BN, 22 [um] SiO₂, 5 [um] Al₂O₃ and 5 [um] TiO₂. For each composite, dielectric constant, dielectric loss, tracking resistance and breakdown field intensity were tested. When BN and SiO₂ particles were added, the dielectric constant and the dielectric loss increased. By co-filling TiO₂ and Al₂O₂ particles to the BN/Epoxy composite, a change in dielectric properties were observed. Different performance among epoxy composites were observed depending on characteristics of the co-filled filler. Experiment results demonstrated the effectiveness of epoxy composites with co-filled micro particles. Results of this research could contribute to optimized design of epoxy composites for improved insulation performance.

A New Bilinear Resistance Algorithm to Analyze the Track-Bridge Interaction on Long-Span Steel Bridge under Thermal Action

In this paper, an analytical algorithm, based on the bilinear resistance model, was proposed to analyze the track-bridge interaction on long-span steel bridges under thermal action. Calculation results show that the proposed algorithm is more accurate than previous analytical algorithms and can achieve nearly the same accuracy as the finite-element method (FEM), but is more efficient than FEM. Based on the algorithm, this paper explained why the longitudinal force (LF) in the middle of the bridges doesn't increase as bridge length increases, then proposed a manual LF calculation formula. Researchers and engineers can use this formula to easily estimate the maximum LF on bridges which have rail expansion devices (REDs). A parametric study was performed. The result shows that LF is not a matter of concern on the bridges with REDs. Besides, the relationships between track resistance distribution, track-bridge relative displacement and boundary conditions were revealed, and the difference between LF on bridge and on embankment were discussed. The outcomes of this paper can be applied to long-span centrosymmetric continuous bridge as well as cable-stayed bridges.

Hospital Antibiotic Stewardship Programs - Qualitative analysis of numerous hospitals in a developing country

SummaryAntimicrobial stewardship programs (ASP) are an essential practice to prevent increasing resistance against antibiotics. A successful ASP monitors not only prescribing patterns and practices but also contributes in minimizing the toxic effects of antibiotics. Moreover, ASP also facilitates the selection of disease specific antibiotics and enforces rules and regulations to rationalize the use of antibiotics. The aim of the study is to highlight the core elements of Hospital Antibiotic Stewardship Programs in Karachi. The key elements proposed by center of disease control (CDC) such as; leadership, accountability, drug expertise, actions to support optimal antibiotic use, tracking (monitoring antibiotic prescribing, use and resistance), reporting information to staff on improving antibiotic use and resistance and education were evaluated on Yes/No scale. The data was collected from 44 hospitals of different categories in Karachi and all the major elements were studied. It was observed that all the hospitals in one setting failed to comply with all the guidelines. It has been concluded that efforts should be made to design ASP at each hospital and implemented through suitable policies and procedures.

Improved flashover performance and tracking resistance of silicone rubber by direct fluorination

ABSTRACTSilicone rubber (SIR) samples are fluorinated using a F2/N2 mixture at different temperatures. Physicochemical characteristics are analyzed by attenuated total reflection infrared spectroscopy, X‐ray photoelectron spectroscopy, and scanning electron microscopy. Basic properties of the fluorinated surface layers are investigated, and the intrinsic alternating current (AC) flashover performance and tracking resistance of the surface fluorinated samples are evaluated. The flashover test results indicate that the fluorination leads to an improvement in AC flashover performance of the SIR material, as a result of the competition between the favorable effect of the increase in surface conduction and the adverse effect of a likely increase in surface layer permittivity. The increase in AC flashover voltage is associated with the voltage‐increasing mode of the flashover test. The flashover test results also show an improved tracking resistance of the SIR material by the fluorination, and the improvement is especially significant for the fluorinated surface layer that has less cleavage of SiC bonds or a good compactness as well as a large thickness. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48556.

A high throughput multi-locus insecticide resistance marker panel for tracking resistance emergence and spread in Anopheles gambiae

The spread of resistance to insecticides in disease-carrying mosquitoes poses a threat to the effectiveness of control programmes, which rely largely on insecticide-based interventions. Monitoring mosquito populations is essential, but obtaining phenotypic measurements of resistance is laborious and error-prone. High-throughput genotyping offers the prospect of quick and repeatable estimates of resistance, while also allowing resistance markers to be tracked and studied. To demonstrate the potential of highly-mulitplexed genotypic screening for measuring resistance-association of mutations and tracking their spread, we developed a panel of 28 known or putative resistance markers in the major malaria vector Anopheles gambiae, which we used to screen mosquitoes from a wide swathe of Sub-Saharan Africa (Burkina Faso, Ghana, Democratic Republic of Congo (DRC) and Kenya). We found resistance association in four markers, including a novel mutation in the detoxification gene Gste2 (Gste2-119V). We also identified a duplication in Gste2 combining a resistance-associated mutation with its wild-type counterpart, potentially alleviating the costs of resistance. Finally, we describe the distribution of the multiple origins of kdr resistance, finding unprecedented diversity in the DRC. This panel represents the first step towards a quantitative genotypic model of insecticide resistance that can be used to predict resistance status in An. gambiae.

Improvement of platinum nanoparticles-immobilized α-zirconium phosphate sheets on tracking and erosion resistance of silicone rubber

Novel platinum nanoparticles immobilized on exfoliated α-zirconium phosphate (Pt@ZrP-E) was prepared and the structure of Pt@ZrP-E was characterized by SEM, TEM and XRD. The effect of Pt@ZrP-E on anti-tracking and erosion properties of Pt@ZrP-E/SiR was investigated. It was found that Pt@ZrP-E can be uniformly dispersed in SiR and SiR containing 0.3 ph Pt@ZrP-E could pass 1A 4.5 kV level. TG results showed that the residues of Pt@ZrP-E/SiR with 0.3 ph Pt@ZrP-E at 700 °C increased from 43.4 wt% to 54.0 wt% compared to SiR. According to the thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) results, the release of carbonyl compounds of Pt@ZrP-E/SiR was decreased but that of CH4 was significantly increased, indicating that Pt@ZrP-E was capable of inhibiting the oxidation of methyl groups and facilitate the cross-linking of SiR under high temperature, which results in the formation of a protective ceramic layer, reduce the ablation from electrical arcing and improve the anti-tracking and erosion properties of SiR.

Efficient identification of preferential flow path in heterogeneous media based on stream function

Existence of preferential flow paths (PFP) in heterogeneous aquifers may dramatically change the behavior of aquifers, making it critical to recognize PFP in solute transport simulation and environmental risk analysis. Conventional particle tracking method can recognize PFP but is computationally demanding and hardly applicable in real high-dimensional problems. Minimum resistance method based on graph theory, though efficient, is unable to consider flow conditions and may lead to implausible path results. In this paper we propose an easy-to-implement method based on stream function to analyze and recognize PFP in heterogeneity of multiple levels. Illustrative examples and robustness tests are reported to demonstrate the effectiveness of the stream function-based method compared with particle tracking and minimum resistance methods. It is found that the proposed method is able to avoid high computational demand and potential conflicts with hydrodynamic conditions thus is both efficient and reliable.

Molecular characterization of bacterial leaf streak resistance in hard winter wheat.

Bacterial leaf streak (BLS) caused by Xanthomonas campestris pv. translucens is one of the major bacterial diseases threatening wheat production in the United States Northern Great Plains (NGP) region. It is a sporadic but widespread wheat disease that can cause significant loss in grain yield and quality. Identification and characterization of genomic regions in wheat that confer resistance to BLS will help track resistance genes/QTLs in future wheat breeding. In this study, we evaluated a hard winter wheat association mapping panel (HWWAMP) containing 299 hard winter wheat lines from the US hard winter wheat growing region for their reactions to BLS. We observed a range of BLS responses among the lines, importantly, we identified ten genotypes that showed a resistant reaction both in greenhouse and field evaluation. ­Genome-wide association analysis with 15,990 SNPs was conducted using an exponentially compressed mixed linear model. Five genomic regions (p < 0.001) that regulate the resistance to BLS were identified on chromosomes 1AL, 1BS, 3AL, 4AL, and 7AS. The QTLs Q.bls.sdsu-1AL, Q.bls.sdsu-1BS, Q.bls.sdsu-3AL, Q.bls.sdsu-4AL, and Q.bls.sdsu-7AS explain a total of 42% of the variation. In silico analysis of sequences in the candidate regions on chromosomes 1AL, 1BS, 3AL, 4AL, and 7AS identified 10, 25, 22, eight, and nine genes, respectively with known plant defense-related functions. Comparative analysis with rice showed two syntenic regions in rice that harbor genes for bacterial leaf streak resistance. The ten BLS resistant genotypes and SNP markers linked to the QTLs identified in our study could facilitate breeding for BLS resistance in winter wheat.

Integrated manufacture of polymer and conductive tracks for real-world applications

The present study demonstrates for the first time a unique UK-designed and built Additive Manufacturing (AM) hybrid system that combines polymer based structural deposition with digital deposition of electrically conductive elements. This innovative manufacturing system is based on a multi-planar build approach to improve on many of the limitations associated with AM, such as poor surface finish, low geometric tolerance and poor robustness. Specifically, the approach involves a multi-planar Material Extrusion (ME) process in which separated build stations with up to 5 axes of motion replace traditional horizontally-sliced layer modelling. The construction of multi-material architectures also involved using multiple print systems in order to combine both ME and digital deposition of conductive material. To demonstrate multi-material 3D Printing (3DP) we used three thermoplastics to print specimens, on top of which a unique Ag nano-particulate ink was printed using a non-contact jetting process, during which drop characteristics such as shape, velocity, and volume were assessed using a bespoke drop watching system. Electrical analysis of printed conductive tracks on polymer surfaces was performed during mechanical testing (static tensile and flexural testing and dynamic fatigue testing) to assess robustness of the printed circuits. Both serpentine and straight line patterns were used in the testing of Ag particle loaded ink and they showed very similar resistance changes during mechanical exposure. Monitored resistance and stress changed as a function of strain exhibiting hysteresis with more prominent residual strain during stretching and compression cycles and 3-point bending flexural tests of PA and CoPA substrates. Bare and encapsulated tracks exhibited low electrical resistivity (1–3*10−6 Ω*m), and its change was more rapid on ABS and minor on PA and CoPA when increasing tensile and flexural strain up to 1.2% and 0.8%, respectively. Resistance of Ag tracks on ABS also increased rapidly during fatigue testing and the tracks easily fractured during repeated stretching-compression cycles at 1% and 1.2% strain. No resistance changes of Ag tracks printed on PA and CoPA were observed at lower strain amplitudes whereas at higher strain amplitudes these changes were the lowest for conductive tracks on CoPA. Thermal analyses were conducted to determine the printed material’s glass transition temperature (Tg), stability and degradation behavior to find the optimum annealing conditions post printing. The novel AM printer has the ability to fabricate fully functional objects in one build, including integrated printed circuitry and embedded electronics. It enables product designers and manufactures to produce functional saleable electronic products. This new technology also gives the opportunity for designers to improve existing products, as well as create new products with the added advantages of geometrically unconstrained 3DP.

Effect of Filler Concentration on Tracking Resistance of ATH-Filled Silicone Rubber Nanocomposites

It is necessary for polymeric materials to have superior tracking resistance against various stress conditions for outdoor applications. In this study, the effect of nano-sized alumina tri-hydrate (ATH) particles on the tracking resistance of silicone rubber (SiR) is studied. Specimens with filler loadings of 1, 3, 5, 10, and 20 wt % are used for performance characterization. From the inclined plane test (IPT) results, apparent improvement in tracking resistance was achieved by mixing 3 wt % of nano-sized fillers, compared to unfilled specimens. ATH/SiR nanocomposites with 5 wt % loading showed comparable tracking performance to SiO2/SiR microcomposites with 20 wt % loading. For detailed analysis, measurements of surface contact angle (SCA) and surface leakage current, and thermo-gravimetric analysis (TGA) were performed. As the nano-ATH filler concentration increased, both thermal stability and leakage current characteristics were improved. Such results agreed with the tracking resistance performance by showing that thermal decomposition and surface charge transport is inhibited in ATH/SiR nanocomposites. Furthermore, performance improvement in nanocomposites was achieved, even at low filler loadings, compared to microcomposites. Meanwhile, the change in SCA was found to be rather limited, regardless of filler loading and filler size.

Acquired NF2 mutations confer resistance to HER2 targeted therapy in HER2-mutant breast cancer.

e12518 Background: Preclinical studies suggest that HER2 mutations lead to constitutive HER2 activation, but knowledge about effective treatment options and clinical resistance mechanisms remain uncharacterized. Methods: We performed dynamic monitoring of &gt;300 serial plasma samples collected from 49 metastatic breast cancer patients used targeted sequencing of 425 clinically relevant genes, to detect HER2 mutations and track resistance to HER2-targeted treatments in HER2-mutant breast cancer. Results: We identified activating HER2 mutations (S310F、D769Y、V777L、778insGSP) in ctDNA and paired tissue samples from four patients with ER positive/HER2-amplification negative metastatic breast cancer, who had developed resistance to multi-line (&gt;3) endocrine therapy. Two patients achieved a durable partial response (approximately 1 years) to trastuzumab combined with everolimus. Intriguingly however, analysis of ctDNA revealed that the NF2 mutation was acquired from a patient with HER2S310F/V777L who had developed resistance to HER2-targeted treatments. We showed that HER2S310F/D769Y/V777L/778insGSP mutations were constitutively active, and T47D and MCF7 overexpressing HER2S310F/V777L/778insGSP were sensitive to HER2 targeted therapies combined with everolimus. Consistent with our clinical findings, NF2 knockdown in HER2 S310F/V777L/778insGSP overexpressing T47D and MCF7 contributed to HER2-targeted therapy resistance. Furthermore, MEK inhibitor remarkably sensitized NF2 knockdown and HER2 mutations co-expressing T47D and MCF7 cells to trastuzumab. Conclusions: Dynamic monitoring of ctDNA could provide the candidate resistance genes for metastatic HER2-mutant breast cancer. Our findings validated NF2 mutations as a potential mechanism of resistance to HER2-targeted therapy, and the combined use of HER2 and ERK inhibitors may overcome resistance to HER2 targeted therapy in HER2-mutant breast cancer.

Enhancing electrical strength of acrylate polymer by using fluorinated monomer as surface modifier

A novel method using ultraviolet (UV) cured fluoralkene to realize surface fluorination of acrylate polymer is proposed to enhance its insulation performance. Doping small amount of dofluoroheptyl methacrylate C11H8F12O2 (DFHMA) in UV acrylate resin formulation as modifier can assemble a fluorinated monomolecular layer on the surface whenas bringing little change to its morphology. The influences of the modifier on molecular structure, surface free energy, elemental composition and electric properties of acrylate polymer are investigated by attenuated total reflection infrared (ATR-IR), water contact angle, X-ray photoelectron spectroscopy (XPS), and electrical performance characterizations, respectively. Experimental results indicate that DFHMA is segregated to the surface of acrylate polymer, leading to an increase of its surface hydrophobicity. Surface flashover tests reveal that fluorinated samples have a higher degradation or tracking resistance in comparison with virgin samples. In addition, strong CF bonds also can enhance bulk breakdown characteristics by increasing charge injection barrier.

Effect of material elasticity on the longitudinal AC breakdown strength of solid-solid interfaces

Solid-solid interfaces between insulating materials dictate the long-term electrical properties of the complete insulation system. This paper presents theoretical and experimental investigations aiming to address the impact of the material elasticity on tangential AC breakdown strength (BDS) of interfaces between polymers. Four different polymers with different elastic moduli were tested using: Cross-linked polyethylene (XLPE), filled epoxy resin (EPOXY), polyether ether ketone (PEEK) and silicone rubber (SiR). The interfaces were formed between identical specimens and were breakdown tested at various contact pressures. It was found that elastic modulus and contact pressure had pronounced effects on the BDS of interfaces. Higher elastic modulus correlated with decreased BDS by a factor of 1.6 at the same contact pressure. On the other hand, the increase of contact pressure by a factor of 3 elevated the interfacial BDS by a factor of 1.4 in the case of the lowest elastic modulus (SiR-SiR) whereas that for the highest modulus (PEEK-PEEK) was about 2.4 times higher. Using the proposed theoretical approach, we postulated that discharged cavities govern the interfacial BDS at the interface together with the electrical tracking resistance of contact area between the cavities. Although the electrical tracking resistance increases with a higher modulus, local field enhancements due to discharged cavities also increase significantly. Therefore, the observed reduction of the BDS with the increase of the elastic modulus is ascribed to the larger cavity size and hence the smaller contact area. It is concluded that increased elasticity reduces the dominance of the discharged cavities over the interface breakdown and increase the governance of the electrical tracking resistance of the contact spots.

A Quick Classifying Method for Tracking and Erosion Resistance of HTV Silicone Rubber Material via Laser-Induced Breakdown Spectroscopy.

Silicone rubber material is widely used in high-voltage external insulation systems due to its excellent hydrophobicity and hydrophobicity transfer performance. However, silicone rubber is a polymeric material with a poor ability to resist electrical tracking and erosion; therefore, some fillers must be added to the material for performance enhancement. The inclined plane test is a standard method used for evaluating the tracking and erosion resistance by subjecting the materials to a combination of voltage stress and contaminate droplets to produce failure. This test is time-consuming and difficult to apply in field inspection. In this paper, a new and faster way to evaluate the tracking and erosion resistance performance is proposed using laser-induced breakdown spectroscopy (LIBS). The influence of filler content on the tracking and erosion resistance performance was studied, and the filler content was characterized by thermogravimetric analysis and the LIBS technique. In this paper, the tracking and erosion resistance of silicone rubber samples was correctly classified using principal component analysis (PCA) and neural network algorithms based on LIBS spectra. The conclusions of this work are of great significance to the performance characterization of silicone rubber composite materials.