World Academy of Science, Engineering and Technology 28 2007
The Effect of Harmonic Power Fluctuation for Estimating Flicker Jin-Lung Guan, Ming-Ta Yang, Jhy-Cherng Gu, Hsin-Hung Chang, and Chin-Lung Huang
Abstract—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 ΔV10 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 power system with electric arc furnaces. This investigation discussed thought the effect of harmonic power fluctuation with flicker estimate value. The method of field measurement, statistics and simulation is used. The survey results demonstrate that ΔV10 estimate must account for the effect of harmonic power variation.
Keywords—Voltage Flicker, Harmonic Power, EAF. I. INTRODUCTION OLTAGE flicker is mainly caused by rapid change of loads in power systems, such as electric arc furnaces (EAF). During the operation of an EAF, the electric poles short circuit and an enormously unstable current is produced, causing current flow to change significantly, and in turn causing serious voltage flickers that influences neighboring power consumers. According to IEEE Std-100 , voltage flicker is luminosity variation or an image disruption caused by lower frequency voltage fluctuations. Power systems currently face serious problems arising from voltage flicker, which is an important threat to power quality , and is currently being targeted by the aggressive power supply quality improvement efforts of the Taiwan Power Company (TPC). Presently, the major source of flicker is the EAF used in steel making plants. Voltage flicker associated with an EAF is evaluated in two main ways around the world. The first is flicker meter, which is the IEC standard and has been established by the UIE . The other is ΔV10 meter, which is established by the Japanese Technical Committee .
Voltage flicker causes sudden flashes of luminosity in fluorescent lamps and electric lights, and consequent eye discomfort, while noticeable, persistent and long-term flicker causes eye tiredness and vision problems. Unstable lighting is thus the most frequent voltage flicker related complain of power consumers. In the case of TV sets, the size of the screen image changes with the intensity of the flicker, while other instances precision electronic equipment also suffers a certain degrees of negative influence from voltage flickers , . Voltage flicker problems have long existed in many of the distribution areas served by TPC, especially those that include steel plants that operate arc furnaces -. When EAF is operating after installation, the power company and steel manufacturers must evaluate the influences of EAF on power systems. Before installing the EAF, capacities of improving facilities related to voltage flicker must be calculated and estimated. Owing to load variation of EAF during steel manufacture being quite violent, the nonlinear phenomenon obviously follows the melt degree of scrap iron. On estimating the severity of voltage flicker, part circuits and load parameters were often ignored and assumed owing to an inability to obtain the true parameters. However, steel factories still experience serious voltage flicker problems even flicker improving facilities has been installed, and thus Guan ,  probes into the differences between the estimated ΔV10 and the survey value of actual EAF operations. This investigation will discuss the relationship between voltage flicker and harmonic power fluctuation for EAF. The flicker phenomenon that the EAF operation causes can apply a reactive power compensation to give an improvement effectively, but if harmonic improvement not appropriate and cause the harmonic resonance enlarge may...
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