Electrical Damage Research Articles

Characteristics and development of damage in the interface of polyimide multilayer films under a repetitive-frequency-pulsed voltage

To study the initiation and development of interfacial electrical damage in multi-layer dielectrics, an aging test of 3-layer polyimide films was conducted under pulsed voltage with a repetitive frequency of 500 Hz and a maximal amplitude of 30 kV. The variation in the damage morphology with the number of applied pulses was analyzed by a statistical method. The circuit current and partial discharge at different aging stages was measured, and the Fourier transform infrared spectrum analysis results of the aged and unaged sample regions were compared. The results demonstrate that the partial discharge in the dielectric interface gap, which is unavoidable in manufacturing, is the main cause of damage. It initiates from the interface and grows into the interior of the dielectric with the application of pulses. When there are no macroscopic defects on dielectric films, damage presents a punctiform morphology. The damage process can be divided into the following three stages: surface roughening damage, steady growth stage of damage points, and pre-breakdown stage. Differing from dielectrics without macroscopic defects, dielectrics with original void defects present transverse dendritic damage channels that initiate from the edge of the defect.

Plasma Surface Modification of 3Y-TZP at Low and Atmospheric Pressures with Different Treatment Times.

The efficiency of plasma surface modifications depends on the operating conditions. This study investigated the effect of chamber pressure and plasma exposure time on the surface properties of 3Y-TZP with N2/Ar gas. Plate-shaped zirconia specimens were randomly divided into two categories: vacuum plasma and atmospheric plasma. Each group was subdivided into five subgroups according to the treatment time: 1, 5, 10, 15, and 20 min. Following the plasma treatments, we characterized the surface properties, including wettability, chemical composition, crystal structure, surface morphology, and zeta potential. These were analyzed through various techniques, such as contact angle measurement, XPS, XRD, SEM, FIB, CLSM, and electrokinetic measurements. The atmospheric plasma treatments increased zirconia's electron donation (γ-) capacity, while the vacuum plasma treatments decreased γ- parameter with increasing times. The highest concentration of the basic hydroxyl OH(b) groups was identified after a 5 min exposure to atmospheric plasmas. With longer exposure times, the vacuum plasmas induce electrical damage. Both plasma systems increased the zeta potential of 3Y-TZP, showing positive values in a vacuum. In the atmosphere, the zeta potential rapidly increased after 1 min. Atmospheric plasma treatments would be beneficial for the adsorption of oxygen and nitrogen from ambient air and the generation of various active species on the zirconia surface.

Spatial electric potential distributions and damage mapping in 3D carbon fiber/epoxy angle-interlock woven composites with different current directions

Exploring electric potential distributions in carbon fiber reinforced polymer composites (CFRPs) is important in electrical-based structural health monitoring for in situ damage detection. Here we investigate influences of current injection angles, electrode locations, and current injection pairs on the electric potential distributions in 3D carbon fiber/epoxy angle-interlock woven (AIW) composites. We have conducted different types of electric potential measurements and established a linear anisotropic conductivity model to reveal the electric potential distributions. It was found that the curved warp yarns form many contacts and increase the conduction path, leading to lower electric conductivity and flatter potential field than those of the weft yarn with straight alignment. The orientation and value of surface electric potential field change depend on current flow direction caused by current injection mode (CIM) and conduction mechanism due to yarn arrangement. Oblique current directed at an angle of 45° is more sensitive in indicating interior damage than that of current parallel to the yarn direction. It is recommended that the oblique current injection should be used to provide effective damage sensing for CFRPs with complex structures.

Алгоритмизация задачи видеоскопического контроля состояния стальных канатов

The paper considers the problem of monitoring the technical state of steel ropes used in industrial and civil installations, such as elevators, cable cars, lifts, etc. To date, the assessment of the state of steel ropes and the safety of their operation is carried out mainly through visual-instrumental control, which is long in time and subject to the influence of the human factor, which determines the relevance of the task of automating this process using computer technology and artificial intelligence methods in order to improve the quality of the assessment, reducing the check interval, detecting defects in steel ropes at an early stage. The article proposes two approaches to the algorithmizing of the problem of videoscopic control of the state of steel ropes using computer vision technologies, based on software modeling of the logic of visual analysis and machine learning methods, such as deep learning artificial neural networks. The authors have developed algorithms for automatic detection of the main types of defects in images of the surface of steel ropes: increase/decrease in diameter, deformation in the form of rope, breaks in the outer wires, thermal and electric damage. The paper presents the results of preliminary testing of the developed algorithms and programs, the composition and methods for determining the main indicators for evaluating their effectiveness are proposed.

Self‐Powered Syringe Pump for Insulin Pump Therapy Based on High‐Voltage Triboelectric Nanogenerator and Dielectric Elastomer Actuator

AbstractInsulin pump therapy (IPT) is commonly utilized for treating type 1 diabetes. However, the insulin pump is generally rigid, and its prolonged use can cause discomfort to patients. Additionally, the device suffers from other drawbacks such as limited battery life. Herein, an IPT system consisting of a dielectric elastomer‐based soft syringe pump (DE‐SSP) and a high‐voltage triboelectric nanogenerator (H‐TENG) is introduced, which can achieve stable and adjustable liquid output depending on real‐time blood glucose. The maximum pump volume of this IPT can reach 262.4 or 303.7 µL when powered by a DC source or H‐TENG, respectively, which is generally sufficient to meet the requirements of the therapy. H‐TENG possesses a sensitive self‐protection mechanism that minimizes the risk of electrical damage and it can be easily fabricated or repaired and flexibly designed according to the application environment. The proposed IPT system is compatible with different placement angles and utilizes compliant electrodes with good biocompatibility that ensure its safety. It also overcomes common issues including rigidness, relatively fixed bolus delivery options, and short battery life associated with traditional insulin pumps. This study not only demonstrates a combination of H‐TENG and DE‐based actuators but also opens new avenues for microelectromechanical systems micropumps.

Modeling the DC and AC electromechanically coupled effects in CNT‐based nanocomposite sensors

AbstractThe direct current (DC) and alternative current (AC) electromechanically coupled phenomena have been reported in carbon nanotube (CNT)‐based nanocomposite sensors. In this contribution, a unified micromechanics‐based model is established for the DC and AC strain sensors. The electric damage and volume change of nanocomposite are considered to be responsible for the electromechanically coupled effects in CNT‐based nanocomposite sensors. The predicted DC resistance change ratio, AC dielectric loss change ratio and corresponding strain sensitivity factors of CNT‐based nanocomposite sensors are all consistent with the experimental results. High strain sensitivity is achieved for CNT‐based nanocomposite sensors with a low CNT‐content. This study confirms the advantage of adopting CNT‐based nanocomposite sensors via the dielectric loss over the electric resistance. The present electromechanically coupled homogenization theory can be utilized to rapidly determine the macroscopic DC and AC sensing performance by choosing a specific set of microstructural parameters, and further simplify the design process of CNT‐based nanocomposite sensors.

Open and shut: Identifying activity patterns by volunteer organizations active in disaster using space-time permutation scan statistics

After a catastrophic flood, the pace of residential cleanup is an important precondition of community resilience. When the process is fast, cleanup reduces additional health or economic risks by preventing structural or electrical damage from escalating. Mobilizing volunteers to complete cleanup work quickly is a challenge that the U.S. Natural Disaster Recovery Framework has assigned to the nonprofit sector. Nonprofit coordination networks—such as those convened through volunteer organizations active in disaster (VOAD) in the United States—aim to create systems of communication that improve the efficiency and equity of post-disaster cleanup. However, the process of coordination and the conditions that encourage quick action remain understudied. The aim of this paper is to identify the impacts of network coordination on the timeline of post-disaster cleanup using geospatial analytics. To do this, we apply a space-time permutation scan statistic (STPSS) to data on the speed at which organizations from the North Carolina VOAD (NC VOAD) closed requests for volunteer assistance following Hurricane Florence in 2018. STPSS results identify clusters of requests that were filled at different speeds through space and time. In total, we identified six space-time clusters indicative of coordinated cleanup. Exploration of clustered data helps to generate new questions about why coordination sometimes happened months after the disaster and suggests ways to use data exploration to inform network function and to leverage the unique capacities of individual nonprofits while also prioritizing housing resilience in socially vulnerable communities.

The Nanoscale Electrical Damage Mechanism of Ge₂Sb₂Te₅ Phase-Change Films Discovered by Conductive Atomic Force Microscopy

We study the nanoscale electrical damage of Ge2Sb2Te5 (GST) phase-change films during crystallization by conductive atomic force microscopy (C-AFM) and Raman spectra. Amorphous GST ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${a}$ </tex-math></inline-formula> -GST) can be converted to crystalline GST ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${c}$ </tex-math></inline-formula> -GST) by applying an exciting direct current (DC) bias (8 V) between the tip and the GST surface. Furthermore, as film thickness increased, the electrical-induced region of GST films revealed a gradual increase in electrical damage and improved crystallinity. It shows that GST films with a thickness of 70 nm have a better crystallization ratio of 20.5 % and less electrical damage with a volume expansion rate of 19.1±6.5%.

Strong Reliable Electrostatic Actuation Based on Self-Clearing Using a Thin Conductive Layer.

Electrostatic adhesion, as a promising actuation technique for soft robotics, severely suffers from the failure caused by the unpredictable electrical breakdown. This study proposes a novel self-clearing mechanism for electrostatic actuators, particularly for electrostatic adhesion. By simply employing an enough thin conductive layer (e.g., <7 μm for copper), this method can spontaneously clear the conductor around the breakdown sites effectively once breakdowns onset and survive the actuator shortly after the electrical damage. Compared with previous self-clearing methods, which typically rely on new specific materials, this mechanism is easy to operate and compatible with various materials and fabrication processes. In our tests, it can improve the maximum available voltage by 260% and the maximum electrostatic adhesive force by 276%. In addition, the robustness and repeatability of the self-clearing mechanism are validated by surviving consecutive breakdowns and self-clearing of 173 times during 65 min. This method is also demonstrated to be capable of recovering the electrostatic pad from severe physical damages such as punctures, penetrations, and cuttings successfully and enabling stable and reliable operation of the electrostatic clutch, or gripping, for example, even after the short-circuit takes place for hundreds of times. Therefore, the proposed self-clearing method sheds new light on high performance and more extensive practical applications of electrostatic actuators in the future.

The influence of pore characteristics on rock fragmentation mechanism by high-voltage electric pulse

High-voltage electric pulse (HVEP) is an innovative low-energy and high-efficiency technique. However, the underlying physics of the electrical breakdown within the rock, and the coupling mechanism between the various physical fields involved in HVEP still need to be further understood. In this study, we establish a 2D numerical model of multi-physical field coupling of the electrical breakdown of porous rock with randomly distributed pores to investigate the effect of pore characteristics (porosity, pore media composition) on the partial electrical breakdown of rock (i.e. the generation of a plasma channel inside the rock). Our findings indicate that the generation of a plasma channel is directionally selective and extends in the direction of a weak electrical breakdown intensity. As the porosity of the rock increases, so does the intensity of the electric field in the ‘electrical damage’ region—the greater the porosity, the greater the effectiveness of rock-breaking. As the fraction of pore fluid (S water/S air) gradually declines, the generation time of the plasma channel decreases, and the efficacy of rock-breaking by HVEP increases. In addition, in this study, we conducted an indoor experiment utilizing an electric pulse drill to break down the rock in order to recreate the growth mode of the plasma channel in the rock. Moreover, the experimental results are consistent with the simulation results. In addition, the development of this type of partial electrical breakdown is confirmed to be related to electrode polarity and pore characteristics via the experiment of the symmetrical needle-needle electrode arrangement, which further demonstrates the mechanism of partial electrical breakdown. This research is significant for comprehending the process of electric impulse rock-breaking and gives theoretical guidance and technological support for advancing electric impulse drilling technology.

Microcapsule-Based Autonomous Self-Healing of Electrical Damage in Dielectric Polymers Induced by In Situ Generated Radicals.

Dielectric polymers are playing important roles in electrical and electronic industries. However, aging under high electric stress is a main threat to the reliability of polymers. In this work, we demonstrate a self-healing method for electrical tree damage based on radical chain polymerization, which is initiated by in situ radicals that are generated during electrical aging. Acrylate monomers contained in microcapsules will be released and flow into hollow channels after the capsules are punctured by electrical trees. Autonomous radical polymerization of the monomers will heal the damaged regions, which is triggered by radicals resulting from polymer chain scissions. After optimizing the healing agent compositions by evaluating their polymerization rate and dielectric properties, the fabricated self-healing epoxy resins showed effective recovery from treeing in multiple aging-healing cycles. We also expect the great potential of this method to heal tree defects autonomously without the need to switch off operating voltages. This novel self-healing strategy will shed light on building smart dielectric polymers with its broad applicability and online healing competence.

Electrical Power Transformer Damage on the Power Grid in Benin: Causes, Consequences and Solution Approaches

The transformer exploits the phenomenon of electromagnetic induction of wound conductors. One of its important properties is that it can act as an impedance matcher. Faults on the electrical network often affect the grounding resistances of power transformers and eventually damage them. Benin's electricity network, like those of other countries in the world, is frequently tested by electrical transformer damage. Through this work, from the static data obtained from the SBEE (Beninese Electric Energy Company), the state of the transformers installed on the electricity network, from 2016 to 2022, is realized. The analysis of their different operating conditions and their installation and protection methods has made it possible to identify the main causes of their damage. Their consequences on the transport and distribution of electrical energy in Benin are highlighted. It appears from this work that most of the faults are due to overvoltage due to discharges, overloads and short circuits. The poles most affected are those on poles (H61) followed by those on frames. Finally, a series of recommendations are proposed to minimize the number of defective transformers.

Development of a novel Electrical Industry Safety Risk Index (EISRI) in the electricity power distribution industry based on fuzzy analytic hierarchy process (FAHP)

Many workers are exposed to electrical energy during the fulfillment of their tasks. It is necessary to identify the potential risk factors for electrical damages. The present study aimed to develop a novel Electrical Industry Safety Risk Index (EISRI) in the electricity power distribution industry based on fuzzy analytic hierarchy process (FAHP). In this study several different safety risk assessment methods were analyzed. Then, common activities in the electricity distribution industry were classified into ten occupational groups. To identify the general structure of risk assessment and determine three main components, including personal, environmental, and organizational a three-stage Delphi study was conducted with the participation of 30 experts. The fuzzy analytic hierarchy process approach was used to weight the components and parameters in each job group. Finally, the results of the EISRI were compared with the failure mode and effect analysis (FMEA) method. The most effective component in determining the risk level was the personal component (PC), with a 0.537 weighted average. Cronbach's alpha values for each of the personal, environmental, and organizational components and the entire model were 0.90, 0.85, 0.82, and 0.86, respectively, and model reliability was confirmed. The results obtained from the EISRI method were compared with the FMEA method, the results of both methods were very close to each other (p < 0.05). The results of this study revealed that the highest weighted average was related to the personal component due to the high impact of the human factors in carrying out activities in various occupations. The EISRI can be applied as a substitute for general risk assessment methods due to the suitability of this method with the nature of activities in this industry. The present technique can be a practical step toward developing suitable risk management algorithm.

Analysis of damage to 35 kv cable lines in the Districts of Tashkent

The article analyzes the damage to the cable line 35 kV in the regions of Tashkent. According to the analysis results, electrical damages in the districts of Tashkent city were detected more often in Shaikhantakhur, Yunsabad, Yashnabad and Almazar districts than in other districts. Electrical damage was mainly in the sleeve -51%, in the cable – 43% and in the funnel – 6%. Moisture, corrosion, mechanical wear, manufacturing defects and other factors are the main causes of this damage.

A UV-responsive mechanically robust insulating polymer that achieves intrinsic self-healing of electrical tree damage based on reversible anthracene photodimerization

Intrinsic self-healing epoxy resin based on reversible anthracene photo dimerization achieves efficient self-healing of scratch damage and electrical tree damage, while maintains high mechanical strength throughout the healing process.

Self-healing of electrical damage in insulating robust epoxy containing dynamic fluorine-substituted carbamate bonds for green dielectrics.

Power systems and electrical grids are critical for the development of renewable energy. Electrical treeing is one of the major factors that lead to electrical damage in insulating dielectrics and decline in the reliability of power equipment and ultimately results in catastrophic failure. Here, we demonstrate that bulk epoxy damaged by electrical treeing is able to efficiently heal repeatedly to recover its original robust performance. The classical dilemma between the insulating properties and electrical-damage healability is overcome by dynamic fluorinated carbamate bonds. Moreover, the dynamic bond enables the epoxy to have admirable degradability, which is demonstrated to be used as an attractive green degradable insulation coating. When used as a matrix for fiber-reinforced composites, the reclaimed glass fibers after decomposing the epoxy maintained their original morphology and functionality. This design provides a novel approach for developing smart and green dielectrics to enhance the reliability, sustainability and lifespan of power equipment and electronics.

Моделирование процесса определения технического состояния тяговых электродвигателей электровозов 2ЭС6

Or positive results in reducing the number of failures of electric traction engines, predictive diagnostics in operation is proposed. The development of malfunctions in electric traction engines directly affects the registration of analog signal values by on-board equipment. Some distinctive criteria have been identified by which the technical condition of electric traction engines can be assessed. The previously developed algorithm for searching for electrical damage has been improved. The presence of a difference in armature current between adjacent bogies and pairs of the same type of electric traction engines is pointed out, the dependence between a serviceable and faulty electric traction engine in the form of discrepancy in correlation coefficients is revealed. All the revealed conditions are added to the algorithm for determining the technical condition, the processes of which are built on the KNIME intelligent analysis platform. The process of determining the technical condition with the output of the result on the serviceability / malfunction of the electric traction engine is modeled. A pair of electric traction motors with a potential malfunction is also identified. The relative modeling error, which is at an average level, allows us to partially solve the problem of occurrence of failures of electric traction engines during operation. The application of the model along with the existing methods improves the quality of predictive diagnostics of modern locomotive equipment.

낙뢰 감지기를 이용한 태양광발전 설비 운영

Lightning not only destroys insulation as an abnormal voltage is induced in the electric circuit, but the current flowing at this time also causes a fire and acts as a factor that promotes the deterioration of parts. Recently, PV power generation devices are spreading from outside the city center to the inside of the city such as houses, apartments, and public offices, so electrical safety issues are emerging. In particular, among the failures of photovoltaic power generation facilities, surge failure accounts for 20% of the total failure rate, and during photovoltaic power generation, tens to hundreds of [A] of energy is emitted, leading to electrical safety accidents through electrical damage to inverters and connection boards. In addition, the frequency of lightning strikes and damage caused by lightning strikes are increasing along with torrential downpours due to extreme weather caused by global warming. In this paper, we intend to study the lightning protection operation system in line with the recent increase in the occurrence of lightning strikes and the resulting increase in electrical safety accidents and the need for safety measures in renewable energy facilities.

Effect of electrical erosion on composite insulator core rod under acidic environment

Silicone rubber housings crack under the combined internal and external factors and expose the core rod. The exposed core rod deteriorates or breaks under electric fields and electrical current. Based on the main characteristics and mechanism of the core rod corrosion, this paper performs an electrical erosion test in an acid-fog environment and analyzes the core rod's macroscopic results and physicochemical properties. The results indicate the following. First, the discharge on core rod during the electrical erosion process contains four consecutive stages. The electrical current, partial discharge, temperature increase, and macroscopic morphology show regular changes at different stages. The arc usually occurs in the carbonization channel, making the channel have the maximum heat. The area of the core rod heating constantly changes but mainly at the high-voltage side and presents as a regional temperature increase. Second, the fracture of glass fiber and ablation of epoxy resin matrix are related to the continuous action of nitric acid. The generation, expansion, and release of pyrolysis gas form bubbles and pores on the epoxy resin matrix. Erosion and pyrolysis cause the loss of the epoxy resin matrix. Third, the combined effect of electrical current, nitric acid, and heat damage the core rod axially and radially. The study provides support for the subsequent core rod deterioration and fracture mechanism.

Improving the irradiation resistance of inverted flexible 3J solar cells by adjusting the structure

Highly efficient, flexible, and lightweight thin-film solar cells play an important role in the aerospace field. To improve the radiation resistance of GaInP/GaAs/InGaAs triple-junction inverted metamorphic (IMM3J) solar cells under intense electron irradiation in space, the back field of the top cell and band gap of the middle cell were optimized. Under 1 × 1015 e/cm2 electron irradiation, compared with the reference cell, the attenuation of the conversion efficiency of the backfield-optimized cell and bandgap-adjusted cell was reduced by 10.3 % and 2.8 %, respectively. According to the spectral response and electrical properties, the current-limiting units of the different cells before and after irradiation were analyzed. The increase in the aluminum (Al) component increased the barrier of the AGaInP back surface field, promoted the carrier absorption of the top cell, and increased the initial current of the solar cell. Optimization of the bandgap in the middle cell enables the bottom cell with a redundant current to resist irradiation attenuation. Both adjustments optimize the current-matching relationship between the sub-cells after irradiation. The decay coefficient of the minority carrier was calculated using the electrical displacement damage theory, and the lifetime decay coefficient of the minority carrier was further estimated, which indicated that the radiation resistance was improved. In addition, the mechanism of improving the radiation resistance is discussed in detail by the characteristics of carrier transport, which provides an optimal direction for improving the irradiation characteristics of solar cells in the future.