Voltage Measurements Research Articles

Controllable Blind AC FDIA via Physics-Informed Extrapolative AVAE

False data injection attacks (FDIAs) targeting AC state estimation pose significant challenges, especially when only power measurements are available, and voltage measurements are absent. Current machine learning-based approaches struggle to effectively control state estimation errors and are confined to the data distribution of training sets. To address these limitations, we propose the physics-informed extrapolative adversarial variational autoencoder (PI-ExAVAE) for generating controllable and stealthy false data injections. By incorporating physically consistent priors derived from the AC power flow equations, which enforce both the physical laws of power systems and the stealth requirements to evade bad data detection mechanisms, the model learns to generate attack vectors that are physically plausible and stealthy while inducing significant and controllable deviations in state estimation. Experimental results on IEEE-14 and IEEE-118 systems show that the model achieves a 90% success rate in bypassing detection tests for most attack configurations and outperforms methods like SAGAN by generating smoother, more realistic deviations. Furthermore, the use of physical priors enables the model to extrapolate beyond the training data distribution, effectively targeting unseen operational scenarios. This highlights the importance of integrating physics knowledge into data-driven approaches to enhance adaptability and robustness against evolving detection mechanisms.

Enhanced current-induced torque efficiency in Pt/Co/Tb/Cr structures through the synergistic action of orbital torque effect

We investigated the impact on the spin–orbit torque (SOT) efficiency by varying the thickness of the Cr and Tb layers in the Pt/Co/Tb/Cr system. The harmonic Hall voltage measurement shows that the Tb insert layer effectively enhances the damping-like (DL) torque efficiency, which is ascribed to the conversion of the orbital current to spin current in the Tb layer. Additionally, by fitting the Cr thickness dependence of the measured DL torque efficiency with an orbital current diffusion model, we obtained the orbital diffusion length of the Cr layer of 5.3 ± 0.3 nm and the effective orbital Hall angle of −0.18 ± 0.01. Furthermore, current-induced magnetization switching measurement suggested that the critical switching current density decreases with the insertion of the Tb layer and the increasing Cr layer thickness. Our findings offer valuable insights into the improvement of SOT efficiency by utilizing the orbital current effect and open avenues for developing energy-efficient spintronics devices.

Finite Element Analysis and Electrohydrodynamic Multiphysics Modeling of a Corona-Streamer Discharge in a Two-Phase Flow Medium

This study proposes an electrohydrodynamic multiphysics modeling and finite element analysis technique to accurately simulate corona-streamer discharges in a two-phase flow medium. The discharge phenomenon is modeled as a multiphysics system, coupling the Poisson equation for the electric field with a charge dynamics model based on fluid methods and a thermofluid field for temperature effects. To optimize the numerical simulation, the tip-flat plate electrode model was simplified to two-dimensional axisymmetry, and an unordered lattice network was used to reduce computational time while maintaining high resolution in the region of interest. A high DC voltage was applied to the model to generate a local non-uniform electric field exceeding 10 MV/m, allowing the numerical simulations of ionization, recombination, and charge attachment in the streamer channel. The numerical results were compared with voltage and current measurements from full-scale experiments under identical geometry and initial conditions to verify the effectiveness of the proposed method. The results of this study enhance the understanding of the multiphysical mechanisms behind electrical discharge phenomena and can enable the prediction of insulation failure through simple simulations, eliminating insulation experiments on devices.

A deep neural network for multi-fault diagnosis of battery packs based on an incremental voltage measurement topology

A deep neural network for multi-fault diagnosis of battery packs based on an incremental voltage measurement topology

A harmonic voltage measurement method based on leakage current of capacitive equipment and measurement system transfer characteristics

A harmonic voltage measurement method based on leakage current of capacitive equipment and measurement system transfer characteristics

Capacitance–Voltage Studies on Electrostatically Actuated MEMS Micromirror Arrays

This article presents the electrostatic actuation performance of micromirror arrays for intelligent active daylight control and energy management in green buildings using a capacitive–voltage (C-V) measurement technique. In order to understand how geometric hinge parameters, initial opening angles, and materials affect the overall efficiency and functionality of the system, micromirror arrays have been analyzed using C-V measurements considering (i) full and broken hinge structures, (ii) 90° and 130° initial tilt angles (Φ), and (iii) different material layer combinations. The measurement results indicate that both an increase in the Young’s modulus of the applied materials and increasing the initial tilt angles increase the threshold voltages during the closing process of the micromirrors.

Design and Implementation of universal converter using ANN controller

This paper details the hardware implementation of a Universal Converter controlled by an Artificial Neural Network (ANN), utilizing key components such as six Insulated Gate Bipolar Transistors (IGBTs), two inductors, and two capacitors for energy storage and voltage smoothing. A Digital Signal Processor (DSP) serves as the core controller, processing real-time input and feedback signals, including voltage and current measurements, to dynamically manage five operational modes: rectifier buck, inverter boost, DC-DC buck, DC-DC boost, and AC voltage control. The pre-trained ANN algorithm generates pulse-width modulation (PWM) signals to control the switching of the IGBTs, optimizing timing and duty cycles for efficient operation. The system effectively accommodates both AC and DC inputs, ensuring stable outputs with minimal ripple by dynamically selecting the appropriate mode based on load requirements. Experimental results demonstrated that the ANN controller maintained total harmonic distortion (THD) below 5% in rectifier and inverter modes while achieving an overall efficiency of 94–96% in DC-DC modes. The controller’s capability to adapt to real-time feedback significantly improved power conversion quality and reduced switching losses. This study confirms the efficacy of the ANN-controlled Universal Converter in meeting the demands of modern power systems through versatile and adaptive control.

Perancangan Dan Pembuatan Plasma Blood Separator Berbasis Arduino Uno

This research aims to design a Plasma Blood Separator that can separate plasma from red blood cells automatical-ly using an Optocoupler sensor and a specimen tube cutter. This sistem is equipped with an Arduino Uno as the con-trolling brain, a servo motor to clamp the hose, a DC motor to open the blood bag pressure, a series of push buttons to open the servo, and a buzzer to indicate the completion of separation. After testing the Arduino Uno-based Plasma Blood Separator, all functions can work well by showing results in three trials varying the length of the tube. The var-ied hose lengths are 38 cm, 52 cm, 71 cm. The estimated separation times are 1.16 minutes, 2.17 minutes and 3.4 minutes. In the voltage measurement results, the measurement results were obtained with a small percentage of error with a value of <5% and a high accuracy value with a value of >90%.

Development of a scaled‐down single‐viaduct model for comprehensive rail potential monitoring and stray current analysis

AbstractThis research investigates the intricate relationship between load variations, environmental conditions, and the resultant stray current generation within DC railway systems. A scaled‐down single‐viaduct model was employed to establish a controlled experimental environment for real‐time monitoring of voltage differentials between the railway tracks and the grounding structure. This research developed a stray current monitoring system for a scaled‐down single‐viaduct model. The system comprises of a power supply, voltage and current measurement capabilities at the power supply, and two levels of stray current measurements at each point. Data such as ambient temperature and humidity, current and voltage at the power supply, and voltage differentials between the railway tracks and the grounding structure are recorded using an Arduino Mega2560 microcontroller. It is hypothesised that stray currents, quantified as voltage differentials between the tracks and the grounding structure, vary in response to changes in load and environmental conditions. Experiments were conducted under various scenarios: variable load, constant load with rain, and constant load across different seasons. The results indicated that with a variable load, the voltage between the tracks increased. During constant load with rain, the average voltage between the tracks rose due to decreased insulation between the tracks and the grounding structure. Lastly, under constant load across different seasons, the most significant voltage change was observed during the rainy season. The findings demonstrate a significant correlation between these variables, with a pronounced influence of environmental conditions, particularly precipitation, on voltage fluctuations. These results underscore the critical importance of effective stray current mitigation strategies for safeguarding the integrity of railway infrastructure and ensuring the safety of personnel. The study offers a valuable contribution to the understanding of stray current phenomena and provides essential insights for the development of advanced protection systems.

Design of On-Site Calibration Device for Electricity Meter Based on Pulse Detection

At present, the error calibration of electricity meters in operation generally adopts an off-site method; that is, the electricity meter is taken out of operation and then calibrated in the laboratory. Off-site calibration, while beneficial, may not fully capture the operational error of the electricity meter due to potential differences in environmental conditions. An on-site calibration device for electricity meters based on pulse detection is designed, which obtains the error of the electricity meter under calibration by comparing the energy pulses of the standard electricity meter with those of the electricity meter under calibration. High-precision voltage and current sampling channels are designed, with a voltage measurement error of less than 0.02% and a current measurement error of less than 0.03%. In response to the non-synchronous sampling problem caused by frequency fluctuations in the on-site verification environment, a fast optimal frequency estimation algorithm is applied to accurately calculate the signal frequency within two cycles. The sampling time interval is adjusted to achieve lock-frequency synchronous sampling, and ensure the accurate calculation of electrical parameters. In order to reduce the complexity of the device circuit structure and equipment cost, a standard electric energy pulses generation method based on digital integration-to-frequency is proposed, which uses software to generate electric energy pulses, with a maximum output frequency of up to 10 kHz. Tests conducted in the laboratory on the developed on-site calibration device for electricity meters show that its accuracy is better than the 0.05 accuracy class, meeting the application requirements for on-site verification of electricity energy meters.

The role of TCNQ for surface and interface passivation in inverted perovskite solar cells

The noticeable growth in the power conversion efficiency of solution-processed organo-inorganic halide perovskite solar cells (OIHPSCs) incited the photovoltaic community to look for limitations that hurdle the commercialization process. The surface and interface defects between the perovskite and electron transport layers are among the main challenges that cause significant non-radiative recombination losses, thereby they result in poor performance and stability. In this work, tetracyanoquinodimethane (TCNQ), a strong electron acceptor molecule, is applied at the interface between the photoactive perovskite and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) layers to modify the interface, and enhance device performance and stability. Steady-state and time-resolved photoluminescence measurements were used to characterize the role of the TCNQ passivation in reducing non-radiative recombination of charge carriers. Current density versus voltage (J-V) measurements show improvement in devices open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF) for devices with TCNQ interface passivation, which is attributed to suppressed non-radiative recombination. In addition, a noticeable improvement in the device’s stability was observed. This study reveals the dual role of TCNQ passivation in improving the photoelectric properties and stability of ambient air processed perovskite devices with the pin architecture.

Adaptive Energy Management Control for Efficiency Improvement of Supercapacitor-Based Energy Recovery System

The efficiency of the DC microgrid can be improved by adding additional energy storage to recover regenerative braking energy. Supercapacitors are well suited for such applications. To make such devices easily connectable to the existing grid, it is beneficial to measure the voltage of the DC bus. The paper proposes a method on how to estimate load current indirectly from this voltage measurement. Estimated current is used in the developed energy management algorithm that adapts current reference of an energy storage system to discharge stored energy in the most energy efficient way. The paper presents simulation and experimental results and shows in some cases efficiency improvement even by more than five percent.

Overview of Wide-Frequency Measurement Technology for Electrical Parameters in Distribution Substations

The rapid development of modern transmission and distribution systems requires transformers with wide bandwidth and high accuracy to meet the measurement needs of new characteristics in distribution substations, including wide dynamic ranges in the time-frequency domain and multi-parameter measurements. This paper outlines the measurement principles and structural design of new wide-frequency voltage and current measurement technologies. Based on the current status and measurement demands of distribution substations, an analysis of the economic, safety, and reliability aspects of these technologies is conducted. The results of the analysis indicate that capacitive voltage transformers and current transformers based on Rogowski coils are the current suitable solutions for wide-frequency measurement in distribution substations. Finally, the paper provides a forward-looking perspective on the development prospects of wide-frequency electrical parameter sensing technologies in distribution substations

Effect of Buffer Layer Formed by Intentionally Induced Heterogeneous Reaction on CIGS Solar Cells

A modified chemical surface deposition (mCSD) method was introduced to confirm the advantages of buffer layers deposited heterogeneously using a solution process mechanism. In chemical bath deposition (CBD), an absorber is immersed in a mixed aqueous solution containing all cation and anion precursors; in chemical surface deposition (CSD), only the absorber surface participates in the reaction using mixed precursor solutions; and in mCSD, each cation and anion precursor reacts separately on the absorber surface, resulting in a heterogeneous reaction. Optimum conditions to form a buffer layer via a heterogeneous reaction in the mCSD process are determined by changing the deposition order of the precursor solution and solution combination. The CdS or Zn(S,O,OH) buffer layers formed under optimal mCSD conditions indicated higher photovoltaic performance in solar cells compared to that of the conventional CdS buffer layer formed by the CBD method. Temperature‐dependent photovoltaic characteristics, capacitance–voltage measurements, and drive‐level capacitance profiling were performed to investigate carrier transport behaviors, confirming that the solar cell with mCSD‐CdS had less interface recombination. Further, the admittance spectroscopy for defect analysis indicated that a solar cell with the mCSD‐processed buffer layer did not form deep defects compared to that with the CBD‐processed buffer layer.

GENERALIZED DEFINITION OF THE APPARENT POWER AND ENERGY-EFFICIENT STRATEGIES OF ACTIVE FILTRATION IN THE REDUCED COORDINATE BASIS OF A MULTIPHASE POWER SUPPLY SYSTEM

The paper substantiates the equivalence of determining the apparent power of a multiphase power supply system with different transmission line impedances using the Fryze-Buchholz-Deppenbrock method and on a reduced coordinate basis. Two energy-efficient control strategies for shunt active filtering in the reduced coordinate basis are proposed. The first strategy provides a unit value of the power factor, and the second strategy minimizes power losses in the transmission line while maintaining symmetry and the quasi-sinusoidal shape of the consumed currents. The advantages of using a reduced coordinate basis are a reduction in the number of sensors and key active filter regulators as well as the absence of the problem to organize the artificial grounding point for phase voltage measurements. A correction factor for the apparent power and power factor formulas was determined and verified in the presence of restrictions on the symmetrical and sinusoidal shape of the consumed currents. References 22, figures 5, tables 2.

Interface Characterization of Plasma‐Treated InAs Electrodes for Resistive Random‐Access Memories Using Capacitance–Voltage Methods

InAs nanowires have been used as selectors and electrodes in a one‐transistor one‐resistor resistive random‐access memory (RRAM) configuration for increased memory scalability. Such oxide‐based memories not only show promise both in conventional memory technology but also as analog memories for neural networks. The small areas of the oxide elements, however, result in challenges for electrical characterization of the oxide–semiconductor interface. By analyzing larger test structures, it is possible to perform impedance spectroscopy on the oxide–InAs interface. In this article, HfO2‐based RRAMs on InAs are fabricated using plasma‐enhanced atomic layer deposition. The effect of the plasma‐length is investigated using capacitance–voltage and DC measurements. It is found that an increased plasma‐length results not only in a higher total electron trapping but also in the formation of a more stable interfacial oxide, possibly related to the stoichiometry of the complex InAs oxide. The findings give us a better understanding of the noise‐ and switching‐performance of scaled nanowire devices.

Analysis of Hot Spots on Photovoltaic Panels

The increase in photovoltaic systems necessitates addressing hot spot issues. Analysis reveals that shading, dust, and manufacturing defects can lead to hot spot formation. A proposed voltage measurement method, based on the Hot Spot Index (HSI), enables hot spot identification and localization. Experiments confirm its effectiveness in detection. Additionally, nearby surrounding areas are also affected, indicating their potential thermal impact. This proactive approach allows minimizing the adverse effects of hot spots on the performance and lifespan of PV systems.

The impact of parasitic capacitances on the accuracy of scale transformation of high-voltage dividers

Purpose. The aim of this work is the determination of the parasitic capacitance’s influence on the accuracy of scale transformation of high-voltage dividers. Analyzing the possibilities of reducing such influence is a pressing problem for high voltage measurement, especially at high frequency range of input voltage. Methodology. Mathematical modeling of the voltage divider equivalent circuit, considering parasitic capacitances and inductances has been performed in the QUCS circuit simulator software under sinusoidal alternating current conditions in the range from 100 Hz to 1 MHz. Using the FEMM software, the finite element method was used to simulate the density distribution of capacitive currents in the module with capacitance graded insulation of the high-voltage arm of the voltage divider. Results. The results of the calculations show that the percentage of parasitic capacitive currents decreases exponentially depending on the ratio of the outer radii of the shielding disks to the distance between them. However, even with the outer radii of the shielding disks of about 3 m, capacitive currents still make up about 1 % of the total current flowing in the measuring circuit of the voltage divider. Instead of increasing outer radii, it is proposed to use high-voltage capacitance graded insulation between the shielding disks. As a result, a stable error of large-scale voltage transformation was obtained when the values of parasitic capacitances change, and it is proposed to manufacture the high-voltage arm of the voltage divider from the same type of high-voltage modules. Originality. The results of modeling the dependence of the accuracy of the voltage divider scale transformation on the ratio of the structural elements geometric parameters of its high-voltage arm were obtained. The solution has been proposed that involves changing the design of the high-voltage arm of the voltage divider, which significantly reduces the dependence of its scale transformation error on significant changes in the parasitic capacitances of the structure components on grounded surfaces. Practical value. The results of mathematical modeling of the characteristics of the voltage divider high-voltage arm make it possible to design, for the purpose of serial production, the same type of high-voltage modules for assembling on-site broadband voltage dividers for any nominal voltage, which will have the possibility of integration into Smart Grid systems. References 23, tables 1, figures 8.

Ultra-low reverse leakage NiOx/β-Ga2O3 heterojunction diode achieving breakdown voltage >3 kV with plasma etch field-termination

This work reports the fabrication and characterization of a NiOx/β-Ga2O3 heterojunction diode (HJD) that uses a metallic nickel (Ni) target to deposit NiOx layers via reactive RF magnetron sputtering and lift-off processing with >3 kV breakdown voltage, ultra-low reverse current leakage under high reverse bias, and a high junction electric field (>3.34 MV/cm). The heterojunction diodes are fabricated via bilayer NiOx sputtering followed by self-aligned plasma-etching for field-termination on both large (1-mm2) and small area (300/100-μm diameter) devices. The HJD exhibits an ∼135 A/cm2 forward current density at 5 V with a rectifying ratio of ∼1010. The minimum differential specific on-resistance was measured to be 17.26/11.64 mΩ cm2 (with/without current spreading). The breakdown voltage on a 100-μm diameter pad was measured to be greater than 3 kV with a noise floor-level reverse leakage current density (10−8 ∼ 10−6 A/cm2) up to 3 kV, accomplishing a parallel-plane junction electric field to be at least 3.34 MV/cm at 3 kV with a power figure of merit >0.52/>0.78 GW/cm2 (with/without current spreading). The temperature-dependent forward current density–voltage (J–V) measurements were performed from room temperature (25 °C) to 200 °C, which showed a temperature coefficient of resistance (α) of 1.56, lower than the value of SiC Schottky barrier diodes.

Resistive Onset Determination of Coated Condutors Utilizing a Shunt Current Instead of Voltage Measurement

Resistive Onset Determination of Coated Condutors Utilizing a Shunt Current Instead of Voltage Measurement