Search results for "AFC"

Series arc faults in AC and DC electrical circuits. Characterization and detection methods

2013

This paper analyzes the problem of the arc faults in both AC and DC low voltage electrical circuits. The state-of-the-art of the arc fault detection methods is analyzed together with the UL 1699 and UL 1699B Standard requirements for protection devices against arc faults (AFCIs). An experimental characterization is carried out of the arc fault phenomenon, for both AC and DC systems, focusing the attention on series arcs. The experimental measurements are carried out on a proper test bench, which has been developed in order to reproduce significant arcing conditions, in accordance with the UL 1699 Standard requirements.

Arc Fault Detection Method Based on CZT Low-Frequency Harmonic Current Analysis

2017

This paper presents a method for the detection of series arc faults in electrical circuits, which has been developed starting from an experimental characterization of the arc fault phenomenon and an arcing current study in several test conditions. Starting from this, the authors have found that is it possible to suitably detect arc faults by means of a high-resolution low-frequency harmonic analysis of current signal, based on chirp zeta transform, and a proper set of indicators. The proposed method effectiveness is shown by means of experimental tests, which were carried in both arcing and nonarcing conditions and in the presence of different loads, chosen according to the UL 1699 standard…

Response of GAFChromic® HD-V2 film dosimeter in 10-300 Gy dose range for radiation testing of electronic devices

2019

The study reported in this paper aimed to investigate the response of a GAFChromic? HD-V2 film dosimeter in the dose range between 10 and 300 Gy, normally used to perform irradiation tests on electronic devices with a 60Co gamma-ray irradiator. The well-defined linearity of response in terms of absorbance as a function of absorbed dose, easiness of handling and data analysis of irradiated dosimeters, reproducibility, stability, and insensitivity to visible light and most of the environmental parameters, make HD-V2 film a flexible, inexpensive and reliable dose measurement device. The study has shown a fogging effect of the dosimeter response since its value changes over time. Strategies and…

Caratterizzazione e metodi di riconoscimento degli arc faults per applicazioni in sistemi di bassa tensione

2013

Survival and gene expression under different temperature and humidity regimes in ants

2017

Short term variation in environmental conditions requires individuals to adapt via changes in behavior and/or physiology. In particular variation in temperature and humidity are common, and the physiological adaptation to changes in temperature and humidity often involves alterations in gene expression, in particular that of heat-shock proteins. However, not only traits involved in the resistance to environmental stresses, but also other traits, such as immune defenses, may be influenced indirectly by changes in temperature and humidity. Here we investigated the response of the ant F. exsecta to two temperature regimes (20 degrees C & 25 degrees C), and two humidity regimes (50% & 75%), for…

ARC FAULT DETECTION EQUIPMENT AND METHOD USING LOW FREQUENCY HARMONIC CURRENT ANALYSIS

2012

An arc fault detection circuit includes a current sensing circuit coupled to a line conductor carrying a current. The current sensing circuit operates to sense current and output data indicative of the sensed current. A processing circuit implements a frequency transform algorithm to transform the output data to frequency data in a low frequency range and with a high spectral resolution where a minimum short time observation window is concerned. The processing circuit identifies an arc fault condition on the line conductor by identifying differences in said frequency data between at least two subsequent observation windows and identifying characteristics which exceed thresholds.

Material, mental, and moral progress : American conceptions of civilization in late 19th century studies on "things Chinese and Japanese"

2015

A Smart Sensing Method for Real- Time Monitoring of Low Voltage Series-Arc-Fault

2020

This paper proposes a smart sensing method for real-time monitoring of low voltage series arc fault. It is based on the wavelet coefficient mean-difference algorithm and the four spikes appearing within two fundamental periods criterion with adaptive threshold. The method also uses the hard thresholding wavelet denoising with the universal threshold. An arc fault factor and a load adaptation factor are introduced and combined with a correction factor, so allowing the selection of the adaptive threshold in real-time and the series arc fault detection.

Integración y transformación económica en África: potencial y limitaciones del Área de Libre Comercio Continental Africana

2021

In March 2018, the African Union gave way to the establishment of the African Continental Free Trade Area, the largest area of economic integration in the world by number of countries involved. As of June 2020, 54 out of 55 African Union member countries have already signed the agreement, thus showing an almost complete unanimity on this topic. AfCFTA comes up when industrialisation strategies and economic transformation in Africa seem to have taken over orthodox structural adjustment and post-adjustment approaches. AfCFTA aims to increase the scarce intra-African trade, boost economic transformation, create the regional value chains and help African firms to join the global value chains. I…

CAD-R. Cuestionario de afrontamiento al dolor crónico: análisis factorial confirmatorio. ¿Hay diferencias individuales en sexo, edad y tipo de dolor?

2017

espanolRESUMEN Introduccion: Se presenta una revision del CAD-R (Cuestionario de afrontamiento al dolor reducido) (1) en una muestra de 4.389 pacientes diagnosticados con dolor cronico derivada de un estudio multicentrico de toda Espana (2). Material y metodo: Se analiza la estructura factorial mediante analisis factorial exploratorio (AFE) y confirmatorio (AFC), asi como la fiabilidad (consistencia interna y test retest a los tres meses, esta ultima sobre 2.825 pacientes). Se ponen a prueba cuatro modelos constatando que las estrategias de primer orden correlacionadas son las que aportan mejores indices de ajuste. Resultados: Tanto los indices de consistencia interna como los test-retest r…