Measurement Of Electrical Parameters Research Articles

Investigation on the Effects of Exchanged Power and Electrode Properties on Micro EDM Drilling of Stainless Steel

Aim of this research is to study how the exchanged power and the electrode material and diameter affect the performance of micro EDM drilling of stainless steel. Copper and tungsten carbide electrodes, with two different diameters, were taken into account. Different values of the exchanged power were obtained by varying the main electrical parameters, namely peak current, voltage and energy level. A dedicated acquisition system for the measurement of effective electrical parameters during the drilling process was implemented. The considered process parameters and the electrode properties, in terms of both material and diameter, resulted to have influence on the drilling performance. Finally, both a linear and non-linear regression approaches were set up to obtain predictive equations about machining time and electrode wear.

Ubicación óptima de PMU considerando restricciones de contingencias N-1 en sistemas eléctricos de potencia

La evaluación de los parámetros eléctricos mediante unidades de medición fasorial en los sistemas de potencia es fundamental, ya que con los datos obtenidos se realiza la estimación del estado de la operación de los mismos. En la presente investigación se plantea el problema para el despliegue óptimo de unidades de medición fasorial respetando restricciones de observabilidad, redundancia y contingencias N-1. La minimización de unidades considera la salida de una línea de transmisión o la falla de una unidad de medición fasorial y garantiza el 100 % de observabilidad de sistema de potencia; para la optimización se utilizó programación lineal entera mixta. El algoritmo propuesto fue probado con los modelos de prueba del IEEE de 9, 14, 30 y 118 nodos.

Flow separation control by pulsed corona actuators

In this experimental work, corona actuators with triangular tips on their anodes are applied on a symmetric airfoil and tested in the wind tunnel at a freestream velocity of 20 m/s (Re = 330k). The actuators are driven by a periodic waveform that improves remarkably their operability with respect to DC driving, increasing also their efficiency. The basic waveform or carrier wave can be modulated introducing a pulsed actuation as usually done for other kinds of plasma actuators. Steady (carrier only) and pulsed (modulated) operation are tested for two actuators, selected out of a larger set previously studied in the laboratory, and compared here with a standard wire-plate corona as reference. The diagnostics include measurements of aerodynamic forces, electrical parameters and local velocities, completed by surface visualizations. Force coefficients and electrical power are used to evaluate the actuators performance in terms of coefficients changes with respect to the smooth airfoil and to the unpowered case, determining also effectiveness parameters in N/W. At the same time, the control mechanism is studied by acquiring boundary layer velocity profiles with plasma off and on, and determining the momentum coefficient of the devices. The passive effects of the unpowered actuators are measured separately and also described by means of surface visualizations. The results confirm the streamwise momentum injection as main mechanism for these actuators, and lead to determine the best flow control achievable by this technique.

Analysis of Electric Power Quantities of Road LED Luminaires under Sinusoidal and Non-Sinusoidal Conditions

The paper presents the results of laboratory tests concerning the measurements of electrical parameters of road lighting luminaires. These measurements were focused on determining the dependence of the electrical parameters of the luminaires versus the changes of the RMS (Root Mean Square) value of the supply voltage and the level of disturbances in the supply voltage. The basic electrical parameters for light-emitting diode (LED) luminaires were analysed with the option of luminous flux adjustment if it existed. During the laboratory measurements, the luminaires were powered from the Agilent 6834B distorted voltage generator within the assumed acceptable range of the changes in the deformation level resulting from the applicable legal provisions for the reproduction of actual power supply conditions.

Light stream emission validation of dipped and full beam headlight designed for HB3 halogen bulb after replacement by LED light source

The article describes analysis of a LED replacement for HB3 halogen bulb. It contains electrical and light parameters measurements of both light source types in terms of lighting the road at dusk and also photometric light shape comparison.

Measurement of Thermal and Electrical Parameters in Photovoltaic Systems for Predictive and Cross-Correlated Monitorization

Photovoltaic electricity generation is growing at an almost exponential rate worldwide, reaching 400 GWp of installed capacity in 2018. Different types of installations, ranging from small building integrated systems to large plants, require different maintenance strategies, including strategies for monitorization and data processing. In this article, we present three case studies at different scales (from hundreds of Wp to a 2.1 MWp plant), where automated parameter monitorization and data analysis has been carried out, aiming to detect failures and provide recommendations for optimum maintenance procedures. For larger systems, the data collected by the inverters provides the best source of information, and the cross-correlated analysis which uses these data is the best strategy to detect failures in module strings and failures in the inverters themselves (an average of 32.2% of inverters with failures was found after ten years of operation). In regards to determining which module is failing, the analysis of thermographic images is reliable and allows the detection of the failed module within the string (up to 1.5% for grave failures and 9.1% of medium failures for the solar plant after eleven years of activity). Photovoltaic (PV) systems at different scales require different methods for monitorization: Medium and large systems depend on inverter automated data acquisition, which can be complemented with thermographic images. Nevertheless, if the purpose of the monitorization is to obtain detailed information about the degradation processes of the solar cells, it becomes necessary to measure the environmental (irradiance and ambient temperature), thermal and electrical parameters (I-V characterization) of the modules and compare the experimental data with the modelling results. This is only achievable in small systems.

Straight waveguide to coaxial adapter of microwave and extremely high frequencies ranges

The paper presents the results of electromagnetic modelling in the computer-aided design system and electrical parameters measurements of microwave band waveguide-to-coaxial adapters. Adapters are developed, manufactured and tested at Micran.

Reliability and quality of power supply to public utilities - case study

The article discusses the problem of supplying electricity to public utilities. Presented are the most important ways of powering objects, ensuring adequate levels of reliability. The results of measurements of electric energy quality parameters carried out at the municipal hospital facility are presented. The possibility of power supply failure in the analyzed public facility was analyzed.

A low cost smart power meter for IoT

The smart city in urban planning and architecture is a set of urban planning strategies aimed at optimizing and innovating public services so as to relate the material infrastructures of cities “with the human, intellectual and social capital of those who live there” thanks to the widespread use of new communication technologies, mobility, environment and energy efficiency, in order to improve the quality of life and meet the needs of citizens, businesses and institutions. Nowadays we hear more and more about the Internet of Things (IoT). Smart devices connected to the internet are increasing in cities. Cities become smart, but at the same time it is not considered the quality of data that these devices send over the internet. The authors, starting from the experience gained previously, in this work focus on energy efficiency, and in particular how energy measurements are performed and sent. The authors propose a low cost smart electric meter for the measurement of electrical parameters. The meter is capable of adapting to the variability of the grid maintaining a high level of measurement accuracy. On the proposed smart meter two algorithms are developed and compared both in simulation and with real signals.

Calibration methods for the simultaneous measurement of the impulse, mass loss, and average thrust of a pulsed plasma thruster

This paper presents calibration devices and methods for the measurement of electric thruster performance parameters using a seesaw-type thrust stand to measure the mass loss of solid propellant in a vacuum. In previous studies, impact hammers and electrostatic combs have been manufactured for the calibration of the thrust and impulse using seesaw-type thrust stands. However, these conventional devices rely on self-calibration, which means that the input delivered by the device in unknown, and must undergo a calibration process themselves. In this paper, the manufactured calibration devices successfully reproduced known impulses, thrusts, and mass losses in a vacuum. By reproducing known inputs based on known masses, the proposed calibration devices can omit the conventionally required self-calibration process. The calibration results showed linear relations between outputs and known inputs and agreed with the theoretical values to within an error of 10%. Additionally, the uncertainties of all known inputs were less than 1.5%. On the basis of these results, the average thrust, impulse, and mass loss were measured using a calibrated thrust stand for the first time. The cumulative impulses obtained from the measured impulse and average thrust agreed with each other to within an error of 5%. The error of the measured mass loss per 1000 shots with respect to the actual mass loss measured using an electronic balance ranged from 1% to 17%.

Design of multi-functional intelligent power monitoring instrument

the real-time detection record of power quality can accurately and quickly analyze the factors that affect the power quality, which is of great significance to improve the national power quality. At present, the electric power monitoring instrument in the market can basically realize the measurement of electric power parameters, but the function is single and the practicability is not strong. So we designed a multi-functional intelligent power monitoring instrument, with three-phase voltage and current detection, harmonic detection, active power and reactive power calculation, electricity calculation, frequency measurement, vector graph, and other functions. The hardware and software design methods of the instrument are described. The window-interpolation FFT algorithm is used to calculate the power parameters, and the sampling frequency can be adjusted in time to reduce the influence of the barrier effect on the system. The test shows that the electric power meter is accurate, small in size, complete in function, simple in operation, and has serial communication function, which is worth popularizing.

Acoustic Power Measurement for a Cylindrical Concave Transducer by using the Self-Reciprocity Method

A novel solution of measuring the acoustic power for a convergent cylindrical wave is proposed based on the self-reciprocity method, which turns the acoustic-power measurement to an electrical-parameters measurement. The formula for estimating the acoustic power was derived for a cylindrical concave transducer. The diffraction and the reflection corrections were also investigated for the precise measurement of the acoustic power. The performance of this method was compared with that of the radiation force balance (RFB) method. The experimental results showed good agreement. Moreover, the self-reciprocity method is more robust to the environment than the traditional RFB method and in practice can be extended to low-level acoustic power measurements.

Entropy of Measurements of Electric and Non-eleCtric Systems Fluctuating Parameters

Fluctuations of the measured parameters of the investigated electric and non-electric systems are considered on the thermodynamics basis. We have defined that entropy of the investigated system in relation to environment depends on the correlation between measuring duration Тmeas of the system’s fluctuation parameter and the system’s relaxation time τ. Decrement of the energy spectrum of fluctuations with the decrease of frequency is explained by Тmeas > τ. When Тmeas ≈ Nmaxτ (where Nmax is the number of possible ways to create the balanced state of the system), entropy of investigated system tends to zero in relation to the environment, and the measurement error caused by fluctuations becomes the minimal.

Dielectric properties of metallic alloy FeCoZr-dielectric ceramic PZT nanostructures prepared by ion sputtering in vacuum conditions

The main objective of the research was investigation of dielectric properties of (FeCoZr)x(PZT)(100-x) granular nanocomposites and determination the influence of isochronous annealing in temperatures of 398 K-573 K on them. The impedance spectroscopy methodology was used. The measurements of electrical parameters, such as: phase shift angle φ, dielectric loss factor tgδ, capacity C and conductivity σ of (FeCoZr)x(PZT)(100-x) nanocomposites have been performed. Frequency dependencies of these parameters were obtained for the ambient temperature range 98 K-373 K for the frequencies ranging from 50 Hz to 105 Hz. It was established, that the conductivity σ of the tested materials before the percolation threshold demonstrates non-linear dependence on frequency. Furthermore, it increases when the ambient temperature is increasing, which indicates a dielectric type of the material. The two types of electrical conduction: capacitive (phase shift angle φ takes negative values) and inductive (φ takes positive values) have been observed. It was concluded that the hopping conductivity dominated in the nanocomposites. Voltage and current resonances phenomena are observed in the materials. The isochronous annealing intensifies the dielectric properties of (FeCoZr)x(PZT)(100-x) nanocomposites.

Underwater archaeological investigation using ground penetrating radar: A case analysis of Shanglinhu Yue Kiln sites (China)

In this study we explored the possibility and effectiveness of applying ground penetrating radar (GPR) to investigate underwater cultural relics. Using this innovative technique, the remains of Yue kiln and anomalous objects buried beneath the lake or suspended in the water can now be fully studied. Although GPR has been widely used for imaging archaeological sites, skepticism remains over its use in underwater archaeology. Nevertheless, some scholars suggest that it is possible to use GPR to detect underwater remains, which has been further confirmed by the use of electrical parameter measurement (EPM) in Shanglinhu Lake. An experiment was performed by our team using antennas of different frequencies in a particular area of the lake. The results showed that the penetrability of the 100 MHz antenna was enough to examine the targets, while the 400 MHz antenna performed well in shallow water (depth <4 m) due to higher resolution. Hence, for our underwater investigation, we used both antennas for maximum coverage. We used a radargram as a topographic map which shows cross sections of the lake. Analysis of the Shanglinhu Lake data indicated that GPR is a superior tool for underwater archaeological investigation. Traditional methods including sonar, underwater cameras and salvage dives were used as supporting techniques in the study.

Limitations on energy resolution of segmented silicon detectors

In the paper experimental study of charge division effects and energy resolution of X-ray silicon pad detectors are presented. The measurements of electrical parameters, capacitances and leakage currents, for six different layouts of pad arrays are reported. The X-ray spectra have been measured using a custom developed dedicated low noise front-end electronics. The spectra measured for six different detector layouts have been analysed in detail with particular emphasis on quantitative evaluation of charge division effects. Main components of the energy resolution due to Fano fluctuations, electronic noise, and charge division, have been estimated for six different sensor layouts. General recommendations regarding optimisation of pad sensor layout for achieving best possible energy resolution have been formulated.

Electrical bioimpedance in patients after ischemic stroke, a civilization disease.

Ischemic stroke is caused by artery blockage, resulting in damage to brain tissue. A significant factor in the further treatment of a patient is not only the time to reach a specialist centre, but also the state of hydration of the organism. Clinical situations involving the excess or deficiency of water can have extremely serious consequences for the functioning of the body and subsequent stroke-related disorders. One of the increasingly common methods of evaluating the composition of the human body is by electrical bioimpedance. The aim of the study was to assess the state of human body hydration measured by bioimpedance in patients with an early stage of ischemic stroke. The examination involved 81 patients with ischemic stroke in the Neurology Department, Subdivision of Stroke Treatment at the Province Specialist Hospital in Lublin, Poland, in 2015. Measurement of the composition and outer and intracellular space of the human body by the Whole Body Bioimpedance (WBIA) method was performed using the Body Composition Monitor (BCM) (Fresenius Medical Care GmbH, Bad Homburg, Germany). A group of patients were been examined with the use of the BIA apparatus three times: on the first, seventh, and tenth day of hospital stay, to determine the level of body hydration. Comparative analysis of data showed that on the first day of hospitalization all the measurements of electrical bioimpedance parameters in the patients were significantly different from those of the control group. In the case of TBW, ECW, ICW, the patients' scores were significantly higher than those of the control group. Only with respect to the over-hydration index, the patients achieved a significantly lower score than the control group. Assessment of hydration status in patients with a diagnosed stroke indicates a slight dehydration in relation to the control group, but falling within the scope of normovolaemia, according to bioimpedance measurement standards.

Real-Time Measurement of Temperature Sensitive Electrical Parameters in SiC Power MOSFETs

This paper examines a number of techniques for junction temperature estimation of silicon carbide (SiC) MOSFET s devices based on the measurement of temperature sensitive electrical parameters for use in online condition monitoring. Linearity, sensitivity to temperature, and circuit design for practical implementation are discussed in detail. A demonstrator based on the measurement of the quasi-threshold voltage, the turn- on transient characteristic ( $di/ dt$ ), the on -state voltage, and the gate current peak is designed and validated. It is shown that the threshold voltage, the estimation of the gate current peak, and the on -state voltage have potentially good sensitivity to temperature variation and linearity over a wide operating range. Very low sensitivity to temperature is shown for $di/ dt$ . The proposed method can provide a valuable tool for continuous health monitoring in emerging applications of SiC devices to high-reliability applications.

Power flow problems with nested information: An approach based on fuzzy numbers and possibility theory

In this paper, we present a new approach based on possibility theory to deal with the power flow problems in electrical networks. The approach takes into account the available information of a power system that is characterized generally by big data, often uncertain, redundant or insufficient for a correct description of the network status. In particular, we present a method to deal with nested information that can be generated by inaccurate measurements of electrical parameters. In order to solve the power flow problem we define a way to model nested information in power system and formalize an AC fuzzy power flow problem. The power flow results are obtained by an innovative approach based on the solution of a simultaneous nonlinear equations fuzzy system. The effectiveness of the proposed method is proven by applying the proposed approach to two modified IEEE benchmark test systems. Simulation results show accuracy, robustness and good computational cost of the implemented method in the search of the solution.

Role of fluorine in two-dimensional dichalcogenide of SnSe2

Authors report an effect of F substitution on layered SnSe2 through the successful synthesis of polycrystalline SnSe2−δFx (0.000 ≤ x ≤ 0.010) by solid-state reaction. Accompanied with density functional theory calculations, the blue shift of A1g peak in Raman spectra reveal that F− ions are substituted at Se vacancy sites as decreasing the reduced mass of vibrational mode associated with Sn–Se bonding. From the measurements of electrical parameters, conductivity as well as carrier concentration are governed by thermally activated behavior, while such behavior is suppressed in Hall mobility, which occurs as F ratio increases. Based on Arrhenius relation, it is found that the potential barrier height at the grain boundary is suppressed with increasing F amount, suggesting that the F− ion is a promising candidate for the grain boundary passivation in the two-dimensional dichalcogenide system.