Influence of Silica (SiO2) Loading on the Thermal and Swelling Properties of Hydrogenated-Nitrile-Butadiene-Rubber/Silica (HNBR/Silica) Composites

Hydrogenated-Nitrile-Butadiene-Rubber (HNBR) is known for its good physical strength. It is a widely used rubber in electrical insulation and other high performance applications. Performance of HNBR is affected in high temperature and an aggressive fluid environment. Adding silica to HNBR may overcome this problem. In order to investigate the effect of fluids and temperature on HNBR/silica composites we prepared multiple composites of HNBR with 8.3, 16.7, 33.4, 50 and 66.7 phr of silica (SiO2) by two roll compounding method. Swelling index and thermo gravimetric analyses were performed. Calculations of swelling indexes were performed at different time periods with ethanol, toluene and water. For thermo gravimetric analysis (TGA), thermo grams of samples were obtained and % char yields at 550 °C were analyzed for all samples. Improvements with the addition of silica were recorded up to a great extent in both analyses. Swelling index decreased with the addition of silica as compared to neat HNBR and reached an optimum position with 50 phr silica loading in ethanol, 8.3 phr in water and 66.7 phr in toluene. Moreover, the HNBR composite with 66.7 phr of silica was found to be the highest thermally stable sample and lost less than 60% of weight at 550 °C in comparison to neat HNBR in which 80% of weight loss occurred at 550 °C

Extension of Optimal Homotopy Asymptotic Method with Use of Daftardar–Jeffery Polynomials to Coupled Nonlinear-Korteweg-De-Vries System

In this paper, Daftardar–Jeffery Polynomials are introduced in the Optimal Homotopy Asymptotic Method for solution of a coupled system of nonlinear partial differential equations. The coupled nonlinear KdV system is taken as test example. The results obtained by the proposed method are compared with the multistage Optimal Homotopy Asymptotic Method. The results show the efficiency and consistency of the proposed method over the Optimal Homotopy Asymptotic Method. In addition, accuracy of the proposed method can be improved by taking higher order approximations

Degradation Performance Investigation of Hydrothermally Stressed Epoxy Micro and Nanocomposites for High Voltage Insulation

Epoxy resins have demonstrated remarkable properties with potential for usage as high voltage insulators. However, a loss of these properties has been observed in high temperature and humid environments. In order to enhance the hydrothermal stability of epoxy resins, micro (15% SiO2) and nano (5% SiO2) silica-based composites of epoxy were fabricated and subjected to standard long term and short term accelerated hydrothermal conditions. To analyze the effect of these stresses, the samples were analyzed periodically through Fourier transform infrared spectroscopy (FTIR) for structure analysis; scanning electron microscopy (SEM) for surface analysis of long-term aged samples; and optical microscopy for the surface topography of short-term aged samples. The Swedish Transmission Research Institute (STRI) classification and contact angle measurement techniques were used for hydrophobicity analysis of long-term and short-term aged samples, respectively. After aging in both conditions, the nanocomposite showed better results as compared to the other samples. After 1000 h of aging, it showed HC-5 class of hydrophobicity, whereas EMC and NE degraded to the HC-6. In case of short-term aging, the contact angle decreased to the 64.15° and 75.05° from 104.15° and 114.9° for ENC and EMC, respectively. Also, in terms of structural degradation, ENC showed the highest structural stability after 1000 h of aging with the highest stable peak of aromatic ether at 1300–1500 cm−1. Microscopic observation through scanning electron and optical techniques also revealed superior performance of the nanocomposites

Improved PVC/ZnO Nanocomposite Insulation for High Voltage and High Temperature Applications

Abstract Nanosized inorganic oxides have the trends to improve many characteristics of solid polymer insulation. In this work, the characteristics of improved poly (vinyl chloride) (PVC)/ZnO are evaluated using 0, 2, 4 and 6 phr of ZnO nanoparticles dispersed in polymer matrix using internal mixer and finally compressed into circular disk with 80 mm diameter using compression molding technique. Dispersion properties are studied by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and optical microscopy (OM). The effect of filler on the electrical, optical, thermal, and dielectric properties of the PVC are also analyzed. Hydrophobicity of nano-composites is evaluated by measuring contact angle and recording hydrophobicity class using Swedish transmission research institute (STRI) classification method. Hydrophobic behavior decreases with the increase in filler content; contact angle increases up to 86°, and STRI class of HC3 for PZ4 is observed. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are employed to evaluate the thermal properties of the samples. Also, continuous decrease of optical band gap energy from 4.04 eV for PZ0 to 2.57 eV for PZ6 is observed. In the meantime, an enhancement in the melting temperature, Tm, is observed from 172 to 215 °C. To check the stability of materials against hydrothermal stresses, all the fabricated materials are then subjected to a hydrothermal aging process for 1000 h and their structural stability is analyzed using optical microscopy and FTIR analyses

Earthing Analysis of High Voltage Laboratory at USPCAS-E, NUST

An effective and reliable grounding system is a necessary parameter for ensuring the safety of test equipment and personnel working in a high-voltage laboratory. This paper analyzes the performance of the grounding system of a high-voltage laboratory located at USPCAS-E, NUST. By using grounding system analysis techniques based on the IEEE standard 80-2013, and programs based on soil-layer models, the grounding system of this high-voltage laboratory is analyzed and solutions to the issues encountered are recommended

Design and Analysis of Shielding for Denoising Sensitive Partial Discharge Measurements in a High Voltage Laboratory

With today’s technological advancements, electromagnetic interference (EMI) in high voltage (HV) Laboratories is extremely important, especially for sensitive Partial Discharge (PD) measurements. To avoid electromagnetic interference during partial discharge studies, the laboratory must be shielded for accurate measurements and findings. There are number of techniques used for shielding to avoid noise during PD measurements, but all the techniques are very expensive and complex. In order to develop a low-cost, practical solution for denoising sensitive PD measurements, two portable prototype models of shielding enclosures based on the operating principle of Faraday Cages are fabricated and used in this research. A comparative analysis of both portable cages was undertaken and effect of the cage’s material on its denoising performance was observed. Practical experimentation yielded effective average noise reduction up to 0.5 pC for 1 kV by a thin aluminum foil cage, and ways to further improve the denoising capability are also suggested

Investigation of Ramped Compression Effect on the Dielectric Properties of Silicone Rubber Composites for the Coating of High-Voltage Insulation

The incorporation of inorganic oxide fillers imparts superior dielectric properties in silicone rubber for high-voltage insulation. However, the dielectric characteristics are influenced by the mechanical stress. The effects of ramped compression on the dielectric properties of neat silicone rubber (NSiR), 15% SiO2 microcomposite (SSMC), 15% alumina trihydrate (ATH) microcomposite (SAMC) and 10% ATH + 2% SiO2 hybrid composite (SMNC) are presented in this study. The dielectric constant and dissipation factor were measured before and after each compression especially in the frequency range of 50 kHz to 2MHz. Before the compression, SSMC expressed the highest dielectric constant of 4.44 followed by SMNC and SAMC. After the compression cycle, SAMC expressed a better dielectric behavior exhibiting dielectric constant of 7.19 and a dissipation factor of 0.01164. Overall, SAMC expressed better dielectric response before and after compression cycle with dielectric constant and dissipation factor in admissible ranges

Investigation of a Battery Storage System Aimed at Demand-Side Management of Residential Load

In this paper, an approach is presented for the demand-side management of residential loads in the urban areas of Pakistan using a battery storage system at the feeder level. The proposed storage system will be installed by a private distributor to supply affordable electricity during peak hours. The experimental data used to carry out this research work are the Pakistan Residential Energy Consumption (PRECON) data set. The households of the data set are categorized based on electric power usage through K-means clustering. The clusters are expanded for feeder synthesis to represent small-scale, medium-scale, and large-scale consumption. This expansion is performed through uniform distribution in a Monte Carlo simulation. The techno-economic analysis for the installation of a battery storage system is carried out for each feeder using SAM. The results of the research project elucidated that the load factors of the feeders representing small-scale, medium-scale, and large-scale consumption improved by 1%, 6%, and 7% by using the optimally sized batteries of 50 kW (670 kWh), 90 kW (1207 kWh), and 100 kW (1360 kWh), respectively. The distributor profit and the consumer utility bill savings ranged from US$12 k to US$25 k. The results proved the validity of the used approach to simultaneously reduce the consumer bill, maximize the distributor profit, and improve the feeder load factor. The novelty of this work lies in the location and in the way the system modeling has been performed with limited data