نتایج جستجو برای: voltage flicker

تعداد نتایج: 110560  

2017
Z. P. Goh M. A. M. Radzi H. Hizam Noor Izzri Abd. Wahab

This paper presents a critical voltage flicker detection based on a pair of inter-harmonics analysis method. The proposed algorithm can be applied in any crowded human place for human awareness purpose. Moreover, the correlation between pair of inter-harmonics and critical voltage flicker is described in details and the related formulas have been derived as well. According to simulation and exp...

2011
Jiří Drápela Jan Šlezingr

Voltage variation is one of lamps flickering main cause; thus evaluation of a disturbing light flicker is a part of voltage quality classification. The instrument for flicker level measurement by means of voltage variation analysis is named flickermeter and is specified in standard EN 610004-15. The flickermeter is a specialized analyzer modeling response of a chain consisting of reference 60W ...

2012
Zhenmei Li Jin Shen Wei Liu YaJing Wang

This paper proposes a new method of monitoring and analyzing voltage flicker based on wavelet packet transform and virtual instrument, and establishes an arithmetic model of the system. First, through the wavelet package transform, we can extract the amplitude modulation waveform, get the accurate time when the voltage flicker occurs and stops, and count the frequency and amplitude of voltage f...

2000
H. C. Huang P. W. Cheng H. S. Kwok

We have performed systematic characterizations of flicker in silicon light valves. It was found that there were four conduction mechanisms accounting for the flicker. These four mechanisms were residual dc charge on the silicon surface, voltage holding capability of the liquid crystal cell, voltage holding capability of the silicon panel, and parasitic capacitor coupling of the pixel. Major cau...

2017
Tiejun Cao

Hilbert Vibration Decomposition (HVD) is introduced to the voltage flicker analysis. When voltage flicker accompanies with high order harmonics, the instantaneous frequency of its analytic signal in principle consists of two different parts, power frequency and a rapidly varying asymmetrical oscillating part. The important property of the instantaneous frequency offers a direct way to estimate ...

2010
Abdolaziz Ashrafian Mehrdad Rostami

In this paper, a method based on continuous wavelet transform is suggested for calculation of flicker power. The flicker power can be utilized to identify the flicker direction to a flicker source with respect to a monitoring point. In our proposed method, using continuous Gaussian wavelet transform, pure flicker waveforms are extracted from the measured voltage and current signals. The flicker...

2016
Amal F. Abd EL-Gawad

Electric Arc Furnaces (EAFs), widely used for steel production industries, are highly nonlinear time-variant disturbing loads because of the random change of the electric arc length results in arc voltage and furnace/supply current fluctuations. Consequently, Power Quality (PQ) problems such as undesirable variations of reactive power, poor power factor, harmonics, and voltage flickers may appe...

2009
J. L. Guan H. H. Chang

Voltage flicker problems have long existed in several of the distribution areas served by the Taiwan Power Company. In the past, those research results indicating that the estimated 10 V Δ value based on the conventional method is significantly smaller than the survey value. This paper is used to study the relationship between the voltage flicker problems and harmonic power variation for the po...

2009
J. L. Guan H. H. Chang

Voltage flicker problems have long existed in several of the distribution areas served by the Taiwan Power Company. In the past, those research results indicating that the estimated 10 V Δ value based on the conventional method is significantly smaller than the survey value. This paper is used to study the relationship between the voltage flicker problems and harmonic power variation for the po...

Journal: :amirkabir international journal of electrical & electronics engineering 2015
m. torabian esfahani b. vahidi

an electric arc furnace (eaf) is known as nonlinear and time variant load that causes power quality (pq) problems such as, current, voltage and current harmonics, voltage flicker, frequency changes in power system. one of the most important problems to study the eaf behavior is the choice of a suitable model for this load. hence, in this paper, a probabilistic three-phase model is proposed base...

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