Dielectric Dissipation Factor Research Articles

Role of charge-compensation process on the structural, microstructure and electrical properties of pure and Nb-doped Sr2SnO4

This article explores the charge compensation method by synthesising Sr2SnO4, Sr2Sn0.99Nb0.01O4, and Sr1.995Sn0.99Nb0.01O4. The synthesis of a monophasic, tetragonal sample was achieved using a typical ceramic approach and high-temperature heat treatment. The XRD followed by Rietveld refinement, confirmed the crystallization of material under the space group I4/mmm. The crystallite sizes for all samples determined to be less than 50 nm, while the micro-strain falls within the range of (1.78–2.93) × 10–3. The microstructure exhibits a cuboidal shape for all samples, and the grain size is observed to decrease with the addition of Nb. The dielectric characteristics of the samples indicate the existence of Maxwell-Wagner and Orientational polarization in the sample. The sample Sr2Sn0.99Nb0.01O4 demonstrates a greater conductivity value compared to Sr1.995Sn0.99Nb0.01O4. This is attributed to the presence of excess electrons that compensate for the overall charge, as opposed to Sr1.995Sn0.99Nb0.01O4 where the extra charge is compensated by a cationic vacancy VSr″. The time-temperature-superposition principle (TTSP) is applicable to all compositions and indicates that similar sources are responsible for both conduction and relaxation processes. The dielectric permittivity and dissipation factor are found to be in the range of 150 to 175 and 0.2 to 0.5, respectively. This suggests that they have potential for future use in millimeter-wave communication with dielectric resonator antennas (DRAs). Due to the presence of oxygen ions and the ability to conduct both ions and electrons, at temperatures above 400 °C, it is a suitable choice for electrode materials in the application of intermediate temperature solid oxide fuel cell (IT-SOFCs). Exploring the manipulation of defects using electrical and ionic charge compensation methods shows potential for enhancing materials in semiconductor technology.

Microcellular long-chain branched polyphenylene oxide (PPO) with excellent comprehensive properties and comprehensive analysis of its dielectric properties

High-frequency and high-speed communications impose stringent requirements on low-dielectric materials with exceptional comprehensive properties. The development of dielectric materials with low dielectric constants and low dielectric dissipation factors holds significant value in reducing interconnect delay, power consumption, and crosstalk in high-frequency communication. In this study, polyphenylene oxide (PPO), known for its excellent properties, was chosen as the base material. Modified PPO with a long-chain branched structure was prepared using the multi-epoxy modifier ADR-4468. The increase in molecular weight and the formation of a long-chain branched structure improved the thermal stability, flexural properties, and foamability of PPO. Introduction of low-dielectric air into the material was achieved through supercritical CO2 foaming, resulting in a series of microcellular PPO foams exhibiting low dielectric properties (with a dielectric constant as low as 1.12 and a dielectric dissipation factor as low as 0.000636). Concurrently, the dielectric properties of microcellular PPO foams were examined at 10 GHz, revealing that the foam’s dielectric properties were minimally impacted by the properties of the raw materials. Based on water absorption analysis, an improved equation for calculating the dielectric dissipation factor was proposed, comprehensively analyzing the influencing factors on the foam’s dielectric dissipation factor. The study unveiled that water absorption significantly affects the foam’s dielectric dissipation factor, and under high expansion ratios, water absorption’s impact on the dielectric dissipation factor exceeds that of air introduction. These microcellular PPO foams, possessing excellent comprehensive properties and low dielectric characteristics, hold promise for applications in the realm of high-frequency and high-speed communications.

Nano and micro co‐filled aluminum nitride/magnesium dihydrate—Silicone rubber composites for high voltage insulation

AbstractCo‐filled composites of micro magnesium dihydrate (MDH) and hydrophobically treated nano aluminum nitride (nH‐AlN) fillers in high temperature vulcanizing silicone gum are studied for thermal and dielectric characteristics for use as an insulating material in high voltage applications. The study begins with description of the compounding protocol adopted, followed by spectroscopic and optical characterization. Fourier transform infrared spectroscopy (FTIR) and energy dispersive X‐ray spectroscopy (EDX) analysis are used to verify the presence of nH‐AlN and MDH in the composites. Thermal analysis through thermogravimetric analysis revealed a stark enhancement in the onset of polymer degradation temperature, with an improvement of 208 °C achieved at 30 phr by weight loading level of MDH. Volume resistivity of 9.71 E14 Ω‐cm is obtained at 30 phr weight loading of MDH and 5 phr of nH‐AlN. AC, +DC, and −DC dielectric strength improved by 1.09, 2.06, and 1.08 times for co‐filled composites at 30 phr MDH and 5 phr nH‐AlN loading levels over unitary filled composite. Effect of dielectric polarization on dielectric constant and dissipation factor is studied at various frequencies. Limitations while conducting dry arc resistance test at standard voltage of 12.50 kV is discussed, with modification in dry arc resistance test voltage to 16.95 kV. The results are presented and discussed here.

Measurement uncertainty in on-line bushing monitoring

The high voltage bushing on-line monitoring has been performed for many years to prevent unexpected rapid power network failures. Network unbalance correction, based on separate voltage phase measurement or phasor technique, effectively improves the measurements of bushing dielectric dissipation factor tgδ and capacitance factor C1. The newly implemented monitoring units reveal that the uncertainty of station voltage measuring transformers manifest the greatest influence on the overall uncertainty budget, regardless of the measurement method.

Probe with a metallic bowl termination to determine the electric material parameters from variable thicknesses

This paper discusses a new approach to determining the material electric parameters (dielectric constant and dissipation factor) through a technique based on identical material variation thicknesses. The copper bowl controls the material thicknesses and allows quick and safe measurements to get to the electromagnetic material information. This approach assumes that the discontinuities generated at the probe and bowl are identical and removed through mathematical operations. The material under test (MUT) gap thickness doesn’t exceed one millimeter. Some formulations have been developed to determine the discontinuity condensers and both capacitors of each thickness. Two proposed developments have been given to extract the complex effective and relative permittivities. A mathematical formula has been proposed to ensure the transition from effective to intrinsic parameters, where the MUT thicknesses and the probe’s outer diameter of the inner conductor are considered. A de-embedding operation is necessary, and the method is suitable but not limited to low-k. The coaxial probe is flat terminated, and the experimental validation has been made in the frequency ranges 1 MHz—2.2 GHz for FR-4 HTG-175 and 1 MHz—0.8 GHz for Alumina 99.5%. All MUTs are 5.0×5.0 cm2, except their thicknesses. The suggested approach is straightforward in sample insertion, simple in data acquisition and implementation, and precise in the final parameters’ results.

Multi-expert GMM decision support system with AHP method for determining weight of transformer oil insulation quality index

The transformer is important and quite central in the power system for distributing energy from generators to consumers through electrical substations. Good transformer oil isolation is needed to protect the transformer to function optimally and prevent fatal interference. Over time, insulating oil experiences aging which can cause transformer damage and disruption in energy distribution to consumers. There are three things that affect the condition of transformer oil insulation, namely chemically testing for acidity, sediment (SED) and water content, from an electrical point of view testing for breakdown voltage (BDV) and testing dielectric dissipation factor (DDF), and from a physical point of view, color, and interfacial tension (IFT) tests are carried out. In dealing with this problem, a Decision Support System (DSS) is needed to calculate the oil quality index based on the given parameters. The method used is Analytical Hierarchy Process (AHP) with multi-expert GMM. The results show that the system is running well, and the calculation method is appropriate. Tests show 100% accuracy in comparing manual calculations with the Confusion Matrix system. Users give an average satisfaction of 92.94%. In conclusion, this system effectively meets the need and helps to determine the quality index of insulating oil in transformers.

Density Functional Theory-Based Approach For Dielectric Constant Estimation of Soluble Polyimide Insulators.

Evaluation of the insulating properties of polymers, such as the dielectric constant and dissipation factor, is crucial in electronic devices, including field-effect transistors and wireless communication applications. This study applies density functional theory (DFT) to predict the dielectric constant of soluble polyimides (SPIs). Various SPIs containing trifluoromethyl groups in the backbone with different pendant types, numbers, and symmetries are successfully synthesized, and their dielectric constants are evaluated and compared with the DFT-estimated values. Two types of DFT-optimized SPIs, single-chain and stacked-chain models, are used to describe the local geometries of the SPIs. In addition, to reveal the relationship between the molecular structure and dielectric constant, further investigations are conducted by considering the dielectric constant of composing ionic and electronic components. The DFT-estimated static dielectric constant of the single-chain model accurately reproduces the corresponding experimental value with at least 80% accuracy. Our approach provides a rational and accelerated strategy to evaluate polymer insulators for electronic devices based on cost-effective DFT calculations.

Synthesis and properties of modified thermoplastic polyimide films with good dielectric properties at high frequency and enhanced thermal stability via incorporation of rigid ester and biphenyl structural units

AbstractA series of ester‐ and fluoro‐containing thermoplastic polyimide (PI) films, PEsI‐1 ~ PEsI‐4 have been prepared by the two‐step thermal imidization procedure via the soluble poly(amic acid) (PEsAA) precursors from the copolymerization of four monomers, including the dianhydrides of bisphenol A dibenzoate‐3,3′,4,4′‐tetracarboxylic acid dianhydride (TMBPA) and 3,3′, 4,4′‐biphenyl tetracarboxylic acid dianhydride (BPDA) and the diamine monomers of 4‐aminophenyl‐4′‐ aminobenzoate (APAB) and 2,2′‐bis(trifluoromethyl)‐4,4′‐diamino biphenyl (TFMB) in the polar aprotic solvent of N‐methyl‐2‐pyrrolidinone (NMP). The PI films obtained from the high‐temperature dehydration of the PEsAA solutions exhibited the good thermal stabilities with the glass transition temperatures (Tg) over 269°C, the 5% weight loss temperatures (T5%) higher than 480°C, and the linear coefficients of thermal expansion (CTE) values in the range of 17.7 × 10−6/K–33.6 × 10−6/K in the temperature range of 50–250°C. Meanwhile, the PI films showed good thermoplasticity in the dynamic mechanical analysis (DMA) tests, in which the storage modulus of the PI films dropped sharply in the temperature range of glass transition of the polymers. At last, the PI films exhibited the good dielectric properties with the breakdown voltages (Vb) over 5200 V, the dielectric strength (Ds) higher than 210 V/μm, the dielectric constants (Dk) in the range of 3.26 ~ 3.32 at the frequency of 10 GHz, and the dielectric dissipation factors (Df) of 0.0038 ~ 0.0047. Compared with the commonly used PEsI‐ref film for high‐frequency flexible copper clad laminates (FCCL), the currently developed PI films exhibited the obviously increased Tg values, decreased CTE values, and comparable dielectric properties.

Investigation of the mechanical, thermal and dielectric properties of electrical corrosion resistance glass reinforced polyimide-based composite produced by spark plasma sintering

Polyimide polymer matrix composites have gained numerous attentions in the design and fabrication of components for automobile, aerospace, and electronics applications as a result of their outstanding properties. Composites are currently replacing polymers as structural, insulation and dielectric materials, and the improvement of mechanical, thermal, and dielectric properties of polyimide (PI) becomes important. Thus, in this paper, the enhancement of the mechanical, thermal stability, and dielectric properties of PI composites with boron-free E-glass (electrical corrosion resistance (ECR) glass) reinforcements (0, 5, 10, and 15 wt%) using Spark Plasma Sintering (SPS) process is presented. X-ray diffractometer, scanning electron microscope (SEM), nanoindentation tests, thermogravimetric analyser, and LCR meter tester were used to investigate the morphology, mechanical, thermal, and dielectric properties of the developed composites, respectively. The SEM results revealed that the ECR-glass powder particles were well dispersed in the PI matrix. The introduction of the ECR into the PI matrix, improves its hardness, stiffness, and modulus. From the obtained results, a notable improvement in its hardness (9.36%), stiffness (30.77%), and modulus (43.58%) was revealed for ECR/PI loaded with 15 wt% ECR compared to pure PI. The thermal stability of the PI composites was observed to be improved with the incorporation of the ECR-glass particles. The heat resistance index of the PI was recorded to be improved by 3.8% at 15 wt% ECR incorporation. Furthermore, the composites depicted low dielectric constant and dissipation factor. In consideration, the obtained properties make the composites promising for mechanical load-bearing, thermal management and electronics applications.

A new technique for fault diagnosis in transformer insulating oil based on infrared spectroscopy measurements

AbstractCondition monitoring of the insulating system within power transformers has a massive importance according to the electrical utilities. Dissolved gas analysis (DGA) is frequently used for this purpose. However, DGA lacks the necessary level of accuracy to identify all equipment faults, particularly in their initial stages of degradation. Also, it does not have the capability for real‐time monitoring and relies on manual sampling and laboratory testing, causing potential delays in fault identification. Additionally, the interpretation of DGA data necessitates specialised expertise, which may pose difficulties for smaller entities that have limited access to resources. Therefore, the contribution of this research is to use infrared spectroscopy measurements as a new effective technique substituting the DGA method for fault diagnosis in insulating oil. The inception faults that were considered in this study were the electrical fault (discharges of high energy) and the thermal fault (300°C < Temperature < 700°C). Regarding that, two test cells were crafted especially for serving the simulation processes inside the laboratory for both types of inception faults. Subsequently, six samples of pure paraffinic mineral oil were taken to be degraded in the laboratory. Following that, all of them besides another sample that were not subjected to any kind of faults were taken to be examined by Fourier transform infrared (FTIR) spectroscopy to obtain an overview of the oil's behaviour in each fault case. After that, the FTIR analysis was initially verified utilising the DGA method. Then, for further affirmation, the dielectric dissipation factor (DDF) for all samples was measured. In the final analysis, the verification tests provide experimental evidence about the outperformance of this new optical technique in detecting the transformer's inception faults in addition to proving its potential for being a superior alternative to the well‐known traditional diagnostic techniques.

Impact of ring structure and conjugation on the dielectric properties of polyimides at a high frequency of 10–40 GHz

AbstractPolyimides (PIs) are widely used materials due to their high thermal stability and potentially low dielectric constant (Dk) and dissipation factor (Df). However, Dk and Df values tend to increase at higher frequencies. Therefore, there is a significant need to reduce the Dk and Df values of PIs, which is the main purpose of this study. This research considers multiple factors, including the ring structures and conjugations on the conformation of the PI backbone. The effects of five‐membered and six‐membered PIs and the conjugated length of benzene and naphthalene structures in the repeating units on the thermomechanical and dielectric properties are systematically investigated. As a result, the PI with a six‐membered imide contributes to higher thermal stability, with a glass transition temperature higher than 350 °C, a thermal decomposition point of 529 °C, and a lower Dk of 2.7–2.8. Still, it exhibits a lower molecular weight than that of a five‐membered imide. On the other hand, PIs with esterified structures show an extremely low Df value, 0.002–0.005. This situation can be attributed to the vital correlation between the Df and the volumetric dipole moment. This study also presents the different properties arising from ring structures and conjugations. Meanwhile, the relationships between Dk and volumetric polarizability and between Df and volumetric dipole moment are confirmed. This work provides a guideline for the structure−dielectric relationship of PI at a high frequency of 10–40 GHz.

Growth mechanism, structure, stoichiometry and optical properties of electrochemically grown iron selenide and ferroselite thin films

In this present work, FeSe and FeSe2 thin films were deposited on ITO substrate at different electrolytic bath temperatures at 30 °C and 70 °C by using electrodeposition method. The growth mechanism was investigated via cyclic voltammetry with the potential window was found to be −1600 to 1600 mV versus SCE and the formation of well adherent film was found to be higher bath temperature. XRD result shows the deposited FeSe and FeSe2 films found to exhibit stoichiometric wurtzite and orthorhombic phases respectively. The microscopic observation shows, the uniform particle growth of FeSe and FeSe2 was found to be higher electrolytic bath temperature at 70 °C. The EDX analysis shows the deposited FeSe and FeSe2 films at higher temperature elemental is stoichiometric ratio. The determined bandgap values for FeSe (1.26 eV) and FeSe2 (1.07 eV) deposited at 70 °C. Also, we observed that the refractive indices (n) values was increased for the film deposited from 30 °C to 70 °C resulting, the estimated refractive indices (n) for FeSe and FeSe2 are 3.16 and 3.45 respectively. Furthermore the most significant optical parameters extinction coefficient (k), optical conductivity (σoptical), real (Ɛ1) and imaginary (Ɛ1) dielectric constants and dissipation factor (tan δ) are determined in order to investigate their usefulness in photovoltaic applications.

Structural, microstructure, spectroscopic, and magnetic investigation of vanadium‐doped SrTiO3 perovskite ceramics

AbstractIn this study, we provide the synthesis and analysis of the structure, microstructure, and spectroscopic properties of V‐doped SrTiO3. The monophasic samples were made using the usual ceramic method, which involved calcination at temperatures of 1000°C and 1300°C. The X‐ray diffraction analysis, combined with the Rietveld refinement, conclusively demonstrates that they have crystallized in a cubic structure, namely under the space group . The inclusion of vanadium (V) at the titanium (Ti) site has been investigated by evaluating the size of the crystallite and grain. The investigation of dielectric and dissipation factors at different frequencies indicates the existence of interfacial and orientational polarization. Two distinct conduction and relaxation processes were identified within the temperature range examined based on the spectroscopic plot. The presence of a paramagnetic phase in the samples, caused by the presence of V and its magnetic interaction with oxygen vacancies, indicates that it can be classified as a soft magnetic material. The electrode's consistent dielectric constant and dissipation factor make it well‐suited for use in supercapacitor dielectric capacitors. Additionally, its mixed‐type conduction, involving both ionic and electronic conduction, makes it excellent for use as electrode materials in intermediate‐temperature solid oxide fuel cells’ applications.

Impact of low molecular weight acid and moisture on the thermal ageing properties of palm oil

<span>This study examines the effect of low molecular weight acid (LMA), moisture and oxygen on the thermal ageing characteristics of refined, bleached, and deodorised palm oil (RBDPO). The paper moisture was varied between 0.5% and 3.5%. The oil was initially subjected to 0.2 g of LMA and 20 mbar of oxygen pressure. The thermal ageing experiment was performed at 120 °C and 140 °C for 28 days. Several dielectric and physiochemical parameters were measured which included dielectric dissipation factor, relative permittivity, resistivity, moisture in oil, acidity, and thermogravimetric analysis (TGA). It is found that LMA and moisture in paper do not affect the <span>relative permittivity of RBDPO and mineral oil (MO). The dielectric dissipation factor of RBDPO and MO reveals slight increment trends within the ageing time. The decrements of resistivities occur after 7 days of ageing</span> <span>for both RBDPO and MO while only RBDPO shows decrement trend of moisture in oil. The ageing patterns of relative permittivities, dielectric dissipation factors and resistivities for RBDPO are similar to MO. The</span> <span>increment of acidity for RBDPO is more apparent that MO throughout the ageing time. All RBDPOs are more resistant to ageing than MO based on the TGA.</span></span>

Effect of voltage harmonics on dielectric losses and dissipation factor interpretation in high-voltage insulating materials

Effect of voltage harmonics on dielectric losses and dissipation factor interpretation in high-voltage insulating materials

Developing a novel optical sensor for condition assessment of aged mineral oil based on carbon dots

Power transformers are major linking equipment in power systems, most of which use oil as insulating medium. This work aims to develop a sensitive opto-active material for effective condition assessment of mineral oil. Thermal aging is performed in the lab under conditions that simulate the actual operation of power transformers. Novel carbon dots are prepared in the lab to be used as an optical sensor for the aged mineral oil. The interaction between a fixed 2 mL of carbon dots and mineral oil samples aged for different times and at different concentrations is studied. A fixed oil concentration of 250 µL is selected and the emission spectra are linearly correlated with aging and dielectric dissipation factor. The in-service limits of dielectric dissipation factor are used to judge the mineral oil’s condition. The obtained photoluminescence spectra proved the suitability of this novel developed carbon dots for condition assessment of mineral oil.

Increasing Twist Rigidity to Prepare Polyimides with Low Dielectric Constants and Dissipation Factors over a Wide Temperature Range

Increasing Twist Rigidity to Prepare Polyimides with Low Dielectric Constants and Dissipation Factors over a Wide Temperature Range

Preparation of fluorinated poly(aryl ether) with high dimensional stability and high temperature resistance by photo‐thermal dual crosslinking reaction

AbstractImproving the dimensional stability is significant for fluorinated poly(aryl ether) (FPAE). In this work, zirconium tungstate (ZrW2O8) with negative thermal expansion (NTE) modified by thiol groups is successfully obtained by surface modification with 3‐(trimethoxysilyl)‐1‐propanethiol. Then, the dispersion of ZrW2O8 is improved and a certain crosslinked structure is formed by click reaction between thiols on the surface of ZrW2O8 and allyl groups on the backbone of FPAE. On this basis, the residual allyl groups on the FPAE can undergo addition reaction under heating conditions to further form crosslinked structure. Due to the introduction of photo‐thermal dual crosslinked structure, the dimensional stability of FPAE is significantly improved, and the coefficient of thermal expansion decreased by 64.3% compared to the unoptimized samples. Meanwhile, the dielectric properties are characterized with dielectric constant and dissipation factor of 3.70 and 0.008 at 1 kHz. Finally, the prepared film is used to assemble triboelectric nanogenerators, where the short‐circuit current, open‐circuit voltage and transferred charge is 3 μA, 30 V, and 10 nC, respectively. Crosslinked FPAE with high dimensional stability and high temperature resistance are successfully gained by avoiding the complexity of monomer synthesis and realizing higher performance with the same inorganic filler loading.Highlights Dual crosslinked structure is built by photo‐thermal dual crosslinking reaction. ZrW2O8 gains homogeneous dispersion in polymer matrix by photo‐crosslinking reaction. Introducing ZrW2O8 and dual crosslinked structure raises dimensional stability of film.

Enhanced thermo-electro-optical and dielectric properties of carbon nanoparticle-doped polymer dispersed liquid crystal based switchable windows

The effect of temperature as well as voltage on switchable smart windows was studied. These smart windows are composites of a polymer and a liquid crystal (LC) and collectively known as polymer dispersed liquid crystal (PDLC) films. In order to enhance the efficiency of the smart windows/PDLC films, the LC material was doped with carbon nano particles (CNP) in various concentrations ranging from 0 to 0.1%. To examine the efficacy and the temperature dependent performance of the CNP doped PDLC (CPDLC) film, firstly morphological and thermo-morphological studies were performed using polarizing optical microscopy (POM). POM in combination with temperature changes allows to record texture changes and the nematic-isotropic transition of the composite films for applied voltage. The complete electro-optical (EO) study comprising of voltage and temperature dependent transmittance, threshold voltage (Vth), saturation voltage (Vsat), contrast ratio (CR) and response time measurement was performed through an assembled EO set-up. To infer intermolecular cooperative processes between polymer and the dipoles of the LC, the relaxation mechanism of the composite films for various temperatures was studied by employing Debye and Cole-Cole models in dielectric spectroscopy. Parameters like dielectric strength and dissipation factor were determined to allow optimization of the CPDLC films.

High Thermally Stable Anthracene-Based Polyimides with Low Dielectric Constants and Dissipation Factors

High Thermally Stable Anthracene-Based Polyimides with Low Dielectric Constants and Dissipation Factors