Search results for "FCI"

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.

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.

Cambiamenti dell'urbanistica. Responsabilità e strumenti al servizio del paese

2017

È possibile immaginare un modo diverso di pianificare le città e i territori? Quali strumenti della cassetta degli attrezzi degli urbanisti sono ancora validi e quali vanno invece aggiornati o abbandonati per renderli efficaci? È possibile trarre un bilancio dal superamento dell’urbanistica come mera regolazione spaziale della città e dall’emergere di un’azione rigeneratrice sollecitata dalla feconda contaminazione con altri saperi, con altre ermeneutiche e con altre semiotiche? Quali effetti della metamorfosi in atto si riflettono sul lavoro degli urbanisti e quali sviluppi futuri è possibile immaginare per rilanciare responsabilità e azione dell’urbanistica al servizio di una nuova idea d…

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.

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

2013

Sign and rank covariance matrices with applications to multivariate analysis

2002

Students’ approaches to solving R-FCI tasks observed by eye-tracking method

2018

This study sought to assess the representational format of task options in the representational variant of the force concept Inventory (R-FCI) test, namely its impact on students’ problem-solving approaches. This was done with the help of eye-tracking equipment. 35 high-school students solved four tasks, mainly from the R-FCI test, which sought to assess the student’s understanding of Newton’s 1st and 2nd Law of Motion. As they were trying to solve the problems, their gazes were tracked by TobiiTX300. A comparison between students who provided the correct and incorrect answer was subsequently carried out. The correctly answering students very quickly found the correct solution both in verba…

Naudas plūsmas pārskata izmantošana uzņēmumu finansiālā stāvokļa novērtēšanā

2016

Katra uzņēmuma veiksmīgas darbības pamatā ir rūpīga tā uzraudzība, kas balstās uz precīzas informācijas bāzes. Lai pierādītu naudas plūsmas nozīmību uzņēmumu finansiālā stāvokļa novērtēšanā, tika nosprausts mērķis: izmantojot piecpadsmit Latvijas Republikā likvidētu un stabilu uzņēmumu finanšu pārskatu datus, izvērtēt naudas plūsmas pārskata nozīmīgumu un izstrādāt priekšlikumus uzņēmumu darbības efektivitātes paaugstināšanai, izmantojot naudas plūsmas pārskata sniegto informāciju. Darba gaitā autore izvirzīja galvenos naudas plūsmas koeficientus un rādītājus, kurus nepieciešams izmantot finansiālā stāvokļa novērtēšanā. Diplomdarba apjoms 74 lapaspuses, darbā iekļauti 16 attēli, 15 tabulas …

Time domain symmetry parameters analysis for series arc fault detection

2022

This paper presents a feasibility study of exploiting the symmetry of some parameters for series arc fault detection in electrical circuits. The considered parameters are defined in the time domain and they are based on the current signal derivative and the evaluation of cross-correlation between subsequent observation windows. The analysis is carried out for AC systems, starting from an experimental characterization, which has been carried out in accordance with the Standard UL 1699 requirements for "unwanted tripping tests"and "operation inhibition tests"of arc fault circuit interrupters (AFCIs). The results obtained in different load conditions show that the proposed parameters can be us…