Leakage Current Test Research Articles

Study on TSV insulating medium based on SACVD process

TSV silicon switching board technology has the advantages of short global interconnection, small delay, low power consumption and high integration. The dielectric insulation performance in the TSV hole will directly affect the signal integrity and power integrity of the TSV silicon switching board. The insulating dielectric layer of TSV requires good forming ability and step covering, and lower leakage current and good heat resistance reliability. In this paper, the filling capacity of SACVD process is analyzed, the coverage rate of SACVD process is studied under different process parameters, and the leakage current of silicon dioxide film is measured by planar capacitance structure. Finally, the leakage current test of the TSV pairs is carried out online. Before the substrate thinning, the leakage current of the two blind hole TSV pairs is measured by the probe station. The voltage ranges form 0 to 50V, and the leakage current ranges from a few pA to a few hundred pA.

Impact of deposition temperature on electrical properties of HZO-based FeRAM

This study presents a comprehensive investigation of the impact of the deposition temperature on the HfxZr1−xO2 (HZO) ferroelectric layer of ferroelectric random access memory with TaN electrodes. This investigation mainly focuses on its electrical characteristics and compares the differences. It is revealed that the deposition temperature plays a crucial role in determining the crystal structure of HZO, which can exhibit a combination of tetragonal and orthorhombic phases or exist solely in one of the two phases. Furthermore, the grain size of HZO varies with the deposition temperature. These findings correspond well to the electrical measurement results, including leakage current, polarization, capacitance, and reliability tests. The study tracks the phase transition process during the operation of switching cycles when the phase transition process can be monitored as well. To better understand the observed differences, physical models that shed light on the underlying mechanisms affected by deposition temperature are proposed at the end of the article.

Power Loss Assessment in Polymer and Ceramic Insulators due to Aging: An Experimental Study

The objective of this study is to analyze the influence of smog on polymer and ceramic insulators, which can lead to flashovers in the distribution network. An experimental chamber was designed to conduct an aging test on the insulators, where in the chamber was subjected to five different types of artificial environments, including rain, temperature, smog, and dust. The chamber was set to replicate the environmental conditions of a smoggy region based on the last five years data for all environmental factors, such as rain, temperature, humidity, smog, and dust. The accelerated aging test was conducted on 11KV-rated polymer and ceramic insulators. The polymer insulator developed contamination of 0.09 gm, while the ceramic insulator showed contamination of 0.13 gm. Furthermore, a leakage current test was performed on the aged insulators, which resulted in 37uA on the polymer insulator and 201uA on the ceramic insulator. The findings suggest that ceramic insulators are more susceptible to the adverse effects of a smoggy environment compared to polymer insulators. Thus, replacing ceramic insulators with polymer insulators in the distribution network not only reduce losses due to the leakage current but it also improve the cost of installation of new distribution networks that can improve the network’s reliability.

Design of Light Emitting Diode-Based Fiber Optic Current Sensor and Its Application in Pollution Flash Prevention in Digitalized Substations

Prevention of pollution flash in electrical equipment in digitalized substations and transmission lines has always been a crucial part of power operation. In order to prevent pollution flash, it is essential to detect the contamination of electrical equipment. The measurement of leakage current is a fundamental aspect of preventive pollution flash work in electrical equipment. Applying fiber optic current sensors to online monitoring systems in the power system offers advantages such as resistance to harsh environments, immunity to electromagnetic interference, and resistance to chemical corrosion. This study designs a unidirectional half-wave fiber optic current sensor based on Light Emitting Diodes (LED) for selectively observing the positive and negative half-cycles of leakage current. Due to the light emission and unidirectional conduction characteristics of LED, with a well-designed circuit, LED performs photoelectric conversion on the current, allowing the sensor to selectively measure the positive and negative half-cycles of leakage current. Subsequently, a combination circuit of silicon detectors and amplifiers is used to complete the photoelectric conversion, facilitating voltage signal measurement. In experiments, the response of the unidirectional half-wave LED fiber optic current sensor reached 37.8 mV/mA, with a detection bandwidth range between [1.2 kHz, 9.8 kHz]. In leakage current tests, using the leakage current of insulators as a reference, experiments were conducted using the voltage boosting method. As the applied voltage increased, the leakage current displayed on the sampling resistor increased, and the measurement waveform indicated that the sensor could correctly select the unidirectional half-wave. In leakage current and salt density tests, the designed fiber optic sensor accurately reflected the exponential relationship between insulator leakage current and contamination, demonstrating the practical value of the designed fiber optic current sensor.

A Dual Carbon Lithium-Ion Capacitor Using Recycled Polymer Separator Derived Carbon Cathode and Graphite Anode from Spent Lithium-Ion Battery

Lithium-ion capacitors (LICs) are hybrid capacitors that target pushing the energy limits of conventional supercapacitors by incorporating a lithium-ion battery (LIB)-type electrode without compromising much on the power density and cycle life of capacitors. Herein, a LIC is assembled using an ordered porous carbon cathode derived from the recycled polymer separator of spent LIBs and recycled graphite anode from the same source. The carbon-rich polymer is thermally stabilized and carbonized to utilize its porosity for ion storage and ordered matrix for better electronic conduction. The cathode half-cell delivers a capacitance of ∼100 F g−1 till 1000 cycles at 1 A g−1. In contrast, the anode half-cell delivers a capacity of 130 mAh g−1 under similar conditions. The assembled LIC provides an energy density of 129 Wh kg−1 at a power density of 275 W kg−1 and 54 Wh kg−1 at a high-power density of 13750 W kg−1. The LIC cycles with >70% capacitance retention till 6000 cycles. Further, the ion-storage mechanism of the LICs as well as their capacitive and diffusion-type contribution, is studied. The self-discharge and leakage current tests were performed in the cells to understand their practical feasibility.

Influence characteristics of water penetration on fibre‐reinforced polymer/rigid polyurethane foam interface of the composite cross‐arm considering natural ageing

AbstractFibre‐reinforced polymer (FRP)/rigid polyurethane foam (RPUF) interface is susceptible to moisture intrusion in addition to natural ageing during operation. This study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics (MD) simulations. Water absorption, shear strength, and leakage current tests were used to clarify the changes in the interface performance. The degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and micro‐characterisation. The results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the interface. In addition, water mainly invades the interface through RPUF. After water penetration, the interfacial bonding strength and insulation performance significantly decreased. Plasticisation and hydrolysis of interfacial materials are the main reasons for decreased interfacial adhesion. Hydrolysis can cause irreversible damage to the interface, increasing interface defects and water absorption. The vicious cycle of material hydrolysis is the ultimate cause of interfacial debonding. The polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.

Detection of crack on a mild steel plate by using a magnetic probe incorporating an array of fluxgate sensors

Magnetic flux leakage (MFL) and eddy current testing (ECT) are two of the most commonly used techniques to detect cracks in ferromagnetic materials. The MFL technique excels in determining the locality of a crack, while the ECT technique can provide useful information regarding the dimension and orientation of cracks. The objective of this research is to propose a simultaneous application of both MFL and ECT techniques in a single probe and to improve the visual resolution of the defect by superimposing signals from a sensor array. A magnetic probe was developed with an array of fluxgate sensors and two excitation coils. Line scan measurements and 2D mapping of artificial slits with different depths were conducted on a mild steel SS400 plate with a thickness of 12 mm to evaluate the performance of the developed probe. The line scan measurement results demonstrated the ability of the probe to detect the presence of artificial slits on the sample and to predict the depth of the slits, especially at the 110-Hz excitation frequency. Then, from the 2D mapping results, the location of the slit was determined. Furthermore, by obtaining a superimposed 2D map generated by each sensor, an improved 2D map resolution with lower background noise was obtained.

Analysis of the hail impacts on the performance of commercially available photovoltaic modules of varying front glass thickness

Hail has a significant impact on the output of photovoltaic (PV) modules. Hence, this paper aims to give complete understanding of hail impacts on PV modules performance analytically and experimentally. The investigation was carried out followed the guidelines as prescribed by the IEC 61215–2:2016/IS 14286: 2019 standard on three PV modules of different thicknesses (2.8 mm, 3 mm, 4 mm) of the front glass. Hail size has been varied from 25 mm to 55 mm, the variation in weight of the ice ball is 7.5 gm to 80 gm, and the variation in speed of the ice ball is from 23 m/s to 34 m/s. After each round of the hail test, the samples are tested for Standard Test Condition (STC), Insulation Test (IT) and Wet Leakage Current Test (WLCT). In addition to measuring electric power output, an electroluminescence (EL) inspection of the cracks of the PV module has been performed. The scientific novelty is the optimization of the PV module based on experimental data under hail tests. Results show that the there is a continuous irreversible effect of the excitation force on the PV modules in the event of hail, and it can reduce the power output. Parametric analysis reveals that the glass thickness of 4 mm is sufficient to withstand severe damage; sample 3 only loses 1.1% of its power output compared to the initial value. However, samples 1 and 2 lose 21.8% and 11.74%, respectively. The insulating resistance of the samples appears to be decreasing with each round of the testing. The % reduction in wet leakage current resistance with respect to the initial value for samples 1, 2 and 3 are 55.25%, 46.81% and 27.23%, respectively. Lesser decrement in wet leakage current resistance indicates that sample 3 is more reliable for the hail-prone area. According to the findings, PV modules with a front glass thickness of 3.2 mm are exemplary when hit by hail up to 35 mm in diameter at a velocity of 27 m/s. However, in hail-prone areas, installers should choose PV modules with a front glass thickness of 4 mm or higher to minimize or eliminate hail damage.

Design and Research of Protection and Action Characteristic Test Device

Before and after the EMC immunity test, it is necessary to verify whether the main performance indicators of the tested equipment are reduced. The protection and action characteristics test device is the equipment to verify the main performance indicators of mining electrical switches and motors. Its research and development involves a variety of equipment to cooperate to realize its system functions. However, there is no single manufacturer in the market to produce such equipment or system, which needs independent research and development according to the needs of the electrical equipment tested in the laboratory. The protection and action characteristic test device is applied to the mechanical characteristic test of high-voltage switch. It can be used as the test equipment for high-voltage and low-voltage leakage action value and time test, as well as the leakage current and capacitive current compensation efficiency test. It can also be used for the characteristic test of the test device, overcurrent protection characteristic test and other test items.

Development of a miniaturized, reconnectable, and implantable multichannel connector

Objective. Connectors for implantable neural prosthetic systems provide several advantages such as simplification of surgery, safe replacement of implanted devices, and modular design of the implant systems. With the rapid advancement of technologies for neural implants, miniaturized multichannel implantable connectors are also required. In this study, we propose a reconnectable and area-efficient multichannel implantable connector. Approach. A female-to-female adapter was fabricated using the thermal-press bonding of micropatterned liquid crystal polymer films. A bump inside the adapter enabled a reliable electrical connection by increasing the contact pressure between the contact pads of the adapter and the inserted cable. After connection, the adapter is enclosed in a metal case sealed with silicone elastomer packing. With different sizes of the packings, leakage current tests were performed under accelerated conditions to determine the optimal design for long-term reliability. Repeated connection tests were performed to verify the durability and reconnectability of the fabricated connector. The connector was implanted in rats, and the leakage currents were monitored to evaluate the stability of the connector in vivo. Main results. The fabricated four- and eight-channel implantable connectors, assembled with the metal cases, had a diameter and length of 6 and 17 mm, respectively. Further, the contact resistances of the four- and eight-channel connectors were 53.2 and 75.2 mΩ, respectively. The electrical contact remained stable during repeated connection tests (50 times). The fabricated connectors with packings having 125%, 137%, and 150% volume ratios to the internal space of the metal case failed after 14, 88, and 14 d, respectively, in a 75 °C saline environment. In animal tests with rats, the connector maintained low leakage current levels for up to 92 d. Significance. An implantable and reconnectable multichannel connector was developed and evaluated. The feasibility of the proposed connector was evaluated in terms of electrical and mechanical characteristics as well as sealing performance. The proposed connector is expected to have potential applications in implantable neural prosthetic systems.

Impacts on insulation resistance of thin film modules: A case study of a flooding of a photovoltaic power plant in Thailand.

Effects of high humid weather conditions on photovoltaic (PV) modules were examined in this study, particularly insulation resistance. Three types of tests were conducted which include leakage voltage test, leakage current test, and wet leakage current test. Due to the usual field constraints in the study of insulation resistance, which limited measurements of leakage current, assurance was made that representative sampling were conducted. The study found a high number of modules with low insulation resistance and high leakage voltage values, which can interrupt the PV plant operation. High leakage voltage creates safety hazards issues. About two third of the samples, which showed deep moisture ingress in the modules, could not pass the minimum criterion of IEC 61646 standard for wet insulation resistance testing. The leakage current results showed the same trend as of leakage voltage, proving that leakage voltage test, which is quite easy and economical, can be used to detect such type of problems in field tests. Prolonged humidity conditions of the PV power plant particularly from natural disaster, should be avoided. Efficient drainage system should be supported in and around installations and all other moisture sources should be regularly removed from the plant area to keep proper operation and minimize losses in energy production.

Study on the difference of fault detection effect of AC leakage current live test technology under operating voltage on different insulating parts of MOA

Resistive current live test plays an important role in the technical supervision of metal oxide arrester (MOA). At the same time, there are some conditions that MOA can not find hidden dangers and defects through AC leakage current live test. This paper puts forward an assumption: the AC leakage current live test technology under operating voltage has different fault detection effects on different insulating parts of MOA. It is found that in the overall AC leakage current composition of the arrester, the resistance sheet and porcelain jacket account for a large proportion, and the proportion of FRP core insulating support rod and epoxy resin insulating cylinder is very small, so the AC leakage current test under operating voltage can effectively detect the faults on the resistance sheet and porcelain jacket, and it is difficult to detect the insulating support rod Fault on insulating cylinder (or insulating package). This study clears a blind spot of the safe operation of the arrester, provides a reference for the condition based maintenance of the arrester, and improves the operation and maintenance level of the arrester.

Testing of planar hydrogenated amorphous silicon sensors with charge selective contacts for the construction of 3D-detectors

Hydrogenated Amorphous Silicon (a-Si:H) is a well known material for its intrinsic radiation hardness and is primarily utilized in solar cells as well as for particle detection and dosimetry. Planar p-i-n diode detectors are fabricated entirely by means of intrinsic and doped PECVD of a mixture of Silane (SiH4) and molecular hydrogen. In order to develop 3D detector geometries using a-Si:H, two options for the junction fabrication have been considered: ion implantation and charge selective contacts through atomic layer deposition. In order to test the functionality of the charge selective contact electrodes, planar detectors have been fabricated utilizing this technique. In this paper, we provide a general overview of the 3D fabrication project followed by the results of leakage current measurements and X-ray dosimetric tests performed on planar diodes containing charge selective contacts to investigate the feasibility of the charge selective contact methodology for integration with the proposed 3D detector architectures.

Feasibility Study on Electrical Properties of 20 kV Polymeric Insulator Dry Test and Rainwater Test

Insulator is a very important equipment in an electric power system. Ceramic insulators have been widely used to support conductors in 20 kV power lines. The problem of ceramic insulators is that they are heavy, easily contaminated on the surface and require a lot of energy in the manufacturing process. Therefore, polymer insulators were developed. This paper presents the design of an epoxy resin polymer insulator with Titanium Dioxide (TiO2) as a nanofiller. The leakage current test was carried out in a high voltage laboratory by applying an AC high voltage of 50 Hz to the insulator dry conditions and the insulator wetted by rainwater contaminants. The results of the leakage current test in dry conditions are 487.6 μA, rainwater contaminated conditions are 594.93 μA, insulation resistance in dry conditions is 2.07 G-Ohms, and contaminated conditions are 1.41 G-Ohms. Based on the test results show that the insulator leakage current increases up to 22% when the surface of the insulator is contaminated with rainwater. Meanwhile, the insulation resistance decreased by up to 32% in conditions contaminated with rainwater. The value of leakage current and insulation resistance indicates that the epoxy resin insulator with TiO2 as filler is electrically feasible to use.

Research of ZnO Arrester Deterioration Mechanism Based on Electrical Performance and Micro Material Test

The traction power supply system of an Electrical Multiple Unit (EMU) often suffers from overvoltage impact. As an important protection device for on-board electrical equipment, the working environment of a roof arrester is worse than that of a power system. In recent years, the explosion failure of the roof arresters of an EMU has occurred from time to time, which seriously endangers the safe operation of high-speed railways. In this paper, the electrical performance test and material micro test of roof arrester in three states of normal, defect, and exploded, are carried out in order to study the internal causes of roof arrester explosion and clarify its deterioration mechanism. Using the DC reference voltage test and leakage current test, the electrical performance differences of normal, defective, and exploded arresters are obtained. By studying the disassembly of an arrester, the appearance characteristics of arrester varistor in three states are obtained. The micro morphology and chemical elements of the varistor are analyzed by Scanning Electron Microscope and Energy Dispersive Spectrometer. The deterioration mechanism of the arrester varistor is then revealed, and preventive measures for the explosion failure of the roof arrester are put forward. The obtained results show that, during the long-term operation of the roof arrester of an EMU, the varistor may be damp, and therefore the aluminum electrode layer and side insulation layer of the varistor may deteriorate. After the deterioration of the aluminum electrode layer, the content of the O element increases, and multiple film structures are formed on the surface. After the deterioration of the side insulating layer, the content of the O element increases, and the surface becomes uneven. Improving the sealing performance requirements of the roof arrester and optimizing the maintenance process can reduce its explosion failure.

Extraction of Flux Leakage and Eddy Current Signals Induced by Submillimeter Backside Slits on Carbon Steel Plate Using a Low-Field AMR Differential Magnetic Probe

Magnetic Flux Leakage (MFL) and Eddy Current Testing (ECT) are commonly employed as the non-destructive evaluation (NDE) techniques used to detect defects within the steel. The MFL technique is advantageous in terms of deep defects detection, while the ECT technique excels in providing dense information regarding defects. In this work, artificial MFL and eddy current (EC) signals in ferromagnetic materials are studied, and an experimental magnetic probe that utilizes both techniques is developed for signal verification. The separation between MFL and EC signals is achieved by utilizing the phase-sensitive detection technique, implementing a dynamic referencing method as opposed to the conventional static phase referencing. A finite element method (FEM) based simulation is employed to study and verify the MFL and EC signals measured by the proposed magnetic probe. The proposed magnetic probe features highly sensitive anisotropic magneto-resistive sensors capable of measuring the MFL and EC signals induced by artificial slits of varying depths engraved onto a 2-mm carbon steel plate. Finite element simulations indicate different flux leakage patterns and eddy current signals detected in the vicinity of the back-side slits. A good agreement is observed between the simulated and the measured MFL and EC signals for the optimized frequency range of 110-210 Hz with the corresponding Lissajous curve for the detection of submillimeter back-side slits. The study has shown that the combination of MFL and EC signals can be successfully captured by an appropriate magnetic probe for an enhanced detection performance of back-side defects in ferromagnetic materials.

Experimental-based models for predicting the flashover voltage of polluted SiR insulators using leakage current characteristics

This study aims to predict the flashover voltage (FOV) of silicone rubber (SiR) insulators. Accordingly, it benefits from two methods, including an artificial neural network (ANN) model and a FOV gradient fitting model. The FOV and leakage current (LC) tests are carried out on one un-aged and three aged specimens under uniform and longitudinal non-uniform pollution circumstances. The proposed ANN model is designed based on equivalent salt deposit density (ESDD), pollution non-uniformity degree, aging time, LC first harmonic magnitude I 1 , and total harmonic distortion. Furthermore, a FOV gradient model is proposed based on ESDD, I 1 , and creepage distance. To validate the proposed models, the FOV and LC tests are conducted on two different types of SiR insulators. Then, the predicted FOV from the ANN model and calculated FOV from the voltage gradient model are obtained. The results indicate that the relative errors of the ANN model and FOV gradient fitting model are <6.4 and 7.3%, respectively.

Inkjet-printed patterned polytitanosiloxane-fluoropolymer composite dielectric layer for micro-optical electrowetting valves

Fluid motion control has always been essential in electrowetting devices. Using the inkjet printing technique, an organic-inorganic hybrid material, polytitanosiloxane, was patterned as a secondary dielectric under the hydrophobic fluoropolymer coating in an optical electrowetting device (OEWD). The effects of different structural parameters of the inkjet-printed polytitanosiloxane (IPP) layer on both the fluid motion at the microscopic level and the macroscopic visual performances of the device were studied experimentally. The leakage-current test was also performed to evaluate the insulating performance of the composite dielectric layer. In addition, COMSOL Multiphysics was used to simulate the fluid flow inside the OEWD with/without the polytitanosiloxane layer. The results showed that, by introducing this IPP layer, precise fluid motion control and improved performance could be obtained.

Synthesis and characterization of hydrophobic nano-silica thin coatings for outdoor insulators

The hydrophobic characteristics of outdoor insulator surface have significant influence on the lifetime and performance of the power transmission lines. In this research, a textured silica layer was dip-coated on the surface using a tetraethyl-orthosilicate (TEOS) containing solution in order to create a hydrophobic surface. Subsequently, the created coating was modified by dipping it in an octadecyl-trichloro-silane/ethanol solution to decrease its surface energy. The coating was characterized by field emission scanning electron microscopy, X-ray diffraction method, Fourier-transform infrared spectroscopy and atomic force microscopy. The microstructural studies confirmed the formation of a uniform microstructure with the mean particle size of 19 nm and roughness of less than 80 nm. The results demonstrated that by creating the hydrophobic coating, the contact angle increased from 14 to 120?. The result of leakage current test at 10 kV showed that the leakage current of the coated insulator was about 24.4 ?A, while that of the non-coated one was about 32 ?A. The adhesion strength of the coating was 1.7MPa.

Investigation of high temperature electrical insulation property of MgO ceramic films and the influence of annealing process

MgO ceramic films were deposited as insulating films for thin film sensors by electron beam evaporation on Ni-based substrate at 25 °C, 200 °C and 300 °C (denoted as MgO-25, MgO-200, and MgO-300). The structures and morphologies of the MgO ceramic films were investigated by X-ray diffraction and scanning electron microscopy, which indicated that MgO films exhibited (111) and (222) preferential orientation growth and a more compact microstructure with increasing substrate temperature. Furthermore, the insulation resistance of MgO films was enhanced at higher substrate temperature, the MgO-300 ceramic film increased by approximately one order of magnitude compared to MgO-25 ceramic film. Notably, the insulation resistance of the MgO-300 ceramic film was 1.5 MΩ when the test temperature reached 1000 °C. Additionally, the influence of annealing on the electrical insulation properties of MgO-300 was evaluated via a leakage current test at 25–1000 °C. The results showed that the stability of the electrical insulation performance was improved mainly due to the growth of grains and repair of defects. Moreover, the conductivity was below 1.2 × 10−6 S/m and the calculated insulation resistance was greater than 0.55 MΩ at 1000 °C after the fourth annealing, which displays that the relative error of the apparent resistance is less than 0.03% by the shunt circuit law. Therefore, their excellent electrical insulation performance demonstrated that MgO films have the potential to be employed as an insulating layer for thin film sensors at high temperature.