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When compared with arc discharge, partial discharge deteriorates silicone rubber more gradually, but its effect on degradation cannot be passed over. Inherently, for a better understanding of silicone rubber deterioration caused by the partial discharge, it seems more research is necessary. In this paper, the acceleration test results on partial discharge degradation of silicone rubber in artificial...
Lead (Pb) is known to be highly poisonous, and the acute poisoning of Cd causes the abdominal pains, vomiting, and shock. The digestive and nervous symptom is observed in the chronic lead poisoning. It was also known that the defect in hemoglobin synthesis by Pb produce anemia. The release of Pb into the environment presents a source of exposure for wild animals. In this study, we examined the utility...
It is well known that non-linear rectifiers generate various harmonics in the power system. To improve those harmonic problems, a lot of original PFC circuits have been proposed so far. Among these, Takahashi, et al, have proposed a PFC scheme using single switching device for single phase boost chopper. For a buck chopper, however, it is difficult to realize the buck chopper in a usual way using...
In recent years, the voltage rise at the end of distribution line and the increase of harmonic voltages has become to be greatly concerned because of extreme expansion of distributed generation (DG) systems and excessive amount of static capacitors (SCs) for improving power factor. For compensating leading current and harmonic currents from consumers, the hybrid type of power quality conditioner was...
This paper presents the line loss minimization control using a UPFC (unified power flow controller) with power flow estimation in a loop distribution system. The minimization of line loss is realized by eliminating the circulating current using the UPFC in the loop system. In the control of the UPFC, all line current in the loop distribution system are necessary. Therefore, the condition and scheme...
Nonlinear rectifier circuits, having capacitors or inductors, are generally used as rectifier circuits, such as those in consumer electronics and appliances. It is known that such rectifiers generate various harmonics in the power system. To reduce these harmonic problems, various original PFC (Power Factor Correction) circuits have been proposed. Amongst these, Prasad-Ziogas, et al, have proposed...
For various rectifier circuits such as those for consumer electronics and appliances, rectifier circuits of the capacitor input type are generally used. It is known that such rectifier generates various harmonics in the power system. To improve those harmonic problems, various PFC circuits have been proposed so far. Among these, Takahashi have proposed a PFC scheme using a LC filter without switching...
Three-phase squirrel-cage induction motors (IMs) are widely used in industrial devices, and most of them are connected directly to the electric power distribution system (PDS). Therefore, it is very important to clarify the effect of the PDS voltage on the characteristic of IM. This paper presents the results of a study on the transient characteristics of an IM under an unbalanced voltage dip. The...
It is a little difficult to obtain the lower dc voltage below the one obtained from input ac supply voltage without transformer or switching operations. Those operations can be implemented by passive devices due to fabrication of electrolytic capacitors. The results are confirmed by the theoretical and experimental implementations.
Various rectifier circuits such as those for consumer electronics and appliances, rectifier circuits of the capacitor input type are generally used. The various harmonics generated within such a power system become a serious problem. Various studies to reduce these effects have been presented so far. However, most of these employ switching devices, such as MOSFETs and the like. Removing the need for...
Various non-linear semiconductor circuits have been used in consumer electronics and industrial electronics. It is well known that rectifier circuits such as these can generate various harmonics within the power system. Because of this, several different power factor correction circuits have been proposed and studied. These methods are designed to improve the input current to a sinusoidal waveform...
We present a novel approach used in conjunction with Sugeno and Yasukawa qualitative modeling algorithm. Its main feature is a reduction of the output space before the output data are clustered. The data used in this paper come from nine diesel engine trucks, and for each diesel engine 13 sensor variables are measured. The objective is to develop a fuzzy model for predicting the remaining lifetime...
This paper presents an elaborated mathematical analysis of the line loss minimum condition of loop distribution systems. In order to achieve this condition, the unified power flow controller (UPFC), a typical FACTS (flexible AC transmission systems) device that is capable of instantaneous control of transmission and distribution power flow, is used. Also, the available control schemes of the UPFC...
For small capacity rectifier circuits such as those for consumer electronics and appliances, rectifier circuits of the capacitor input type are generally used. The various harmonics generated within such a power system become a serious problem. Various studies to reduce these effects have been presented so far. However, most of these employ switching devices, such as MOSFETs and the like. Removing...
For consumer electronics and appliances, rectifier circuits of the capacitor input type are generally used. The various harmonics generated within such a power system become a serious problem. Various studies to reduce these effects have been presented so far. However, most of these employ switching devices, such as MOSFETs and the like. Removing the need for switching devices renders the systems...
The line impedance could be measured by means of only passive elements such as inductors or resistors, that is presented at first. However, as the voltage and current used for the measurement are increased, the size of the inductor or resistor being used also needs to be increased, so in practice it would be virtually impossible to make an accurate measurement. Because of this, we have developed a...
The line impedance could be measured by means of only passive elements such as inductors or resistors, that is presented at first. However, as the voltage and current used for the measurement are increased, the size of the inductor or resistor being used also needs to be increased, so in practice it would be virtually impossible to make an accurate measurement. Because of this, we have developed a...
The five-level PWM inverter has many advantages such as ability to operate the AC motors or the power compensator with very large capacity in nearly sinusoidal current waveforms. For these reasons, these applications have just begun to study. However, this circuit must provide four DC power supplies for supplying the active power. In this paper, we propose a novel double power supply method, in which...
Capacitor input-type rectifier circuits are generally employed in small-capacity rectifier circuits, such as those used for consumer electronics and appliances. Consequently, the various harmonics that are generated in the power system become a serious problem. Various studies of these issues have been reported. However, most of those methods employ switching devices, such as FETs and the like. The...
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