نتایج جستجو برای: harmonic impedance
تعداد نتایج: 82738 فیلتر نتایج به سال:
A Method for Determining Customer and Utility Harmonic Contributions at the Point of Common Coupling
A new method is proposed in this paper to determine the harmonic contributions of a customer at the point of common coupling. The method can quantify customer and utility responsibilities for limit violations caused by either harmonic source changes or harmonic impedance changes. It can be implemented in current power quality monitors and digital revenue meters. The method makes it possible to ...
Matching the impedance of an artificial lung for pulmonary replacement to native pulmonary impedance is important in preventing right ventricular dysfunction. A lumped-parameter theoretical model and bench-top experiments were used to investigate the effect of a prototype compliance chamber on input impedance. The bench-top simulation consisted of a pulsatile flow generator, a prototype complia...
harmonics have become an important issue in modern power systems. the widespread penetration of non-linear loads to emerging power systems has turned power quality analysis into an important operation issue under both steady state and transient conditions. this paper employs an extended harmonic domain (ehd) based framework for dynamic analysis of long term analysis over voltages during the tra...
To achieve accurate reactive power and harmonic currents sharing among inverter interfaced distributed generation (DG) units in islanded microgrids, a hierarchal control scheme consisting of primary and secondary levels based on instantaneous circulating currents is proposed in this paper. Firstly, fundamental and main harmonic components of each inverter output current are extracted at the pri...
The modern wind turbines (WT), equipped with power converters (full or partial power converters) connected to the grid, have increased rapidly in recent years. Harmonic assessment of the power quality is a necessary study for interconnection of future wind farm to the grid. Normally, the power quality assessment in wind farm is done considering the power converter as an ideal harmonic current s...
Complex impedance and conductivity were measured for regioregular poly(3hexylthiophene) (P3HT) at alternating current (AC) voltages using a waveform technique. The waveforms were Fourier transformed from time domain to frequency domain and analyzed at fundamental and higher order harmonic frequencies. It was found that the impedance of the semi-conducting P3HT decreases with increasing electric...
Mice are used with increasing frequency as models of human cardiovascular diseases, but significant gaps exist in our knowledge of vascular function in the aging mouse. We determined aortic input impedance spectra, pulse wave velocity, and augmentation index in adult (8-mo-old) and old (29-mo-old) mice to determine whether arterial stiffening occurred with age in mice as it does in humans. Pres...
This paper addresses a cause for false tripping of photovoltaic inverters with anti-islanding protection based on impedance measurement with inter-harmonic injection. Earlier discussions about tripping problems happening when several devices are doing the measurement at the same time are supplemented with a problem caused by inrush transients of nearby devices. A series of experiments was condu...
We analyze in which experimental conditions the concept of electrical impedance is useful for an electrolytic cell. The analysis is performed by solving numerically the differential equations governing the phenomenon of the redistribution of the ions in the presence of an external electric field and comparing the results with the ones obtained by solving the linear approximation of these equati...
High impedance fault HIF produced when an energized conductor falls and contact with an objects have high impedance like: tree limb, concrete walls, or falls down to the ground. The importance of these undetectable faults is represent a safety hazard, also a risk of arcing that causes ignition of fires. This type of fault is cannot be detected by overcurrent protections . The techniques of dete...
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