Why is the harmonic current on the null line mainly three times? This is due to two reasons: (1) Among the harmonic components generated by single-phase rectifier circuit, the third harmonic is the largest, and the distortion rate of the third harmonic usually reaches more than 80%. (2) The harmonic current of other times will have the effect of canceling on the zero line, onl...
What is power quality? The IEC (1000-2-2/4) standard defines power quality as follows: power quality refers to the physical characteristics of power supply devices that do not interrupt or interfere with users' use of power under normal working conditions. The most serious power quality problems are voltage sags and complete voltage interruptions. In fact, power quality refers to the...
Due to the rapid development of power electronic technology, the nonlinear characteristics of industrial and agricultural power loads, especially transportation and civil electrical products are becoming more and more serious, and the power factor of users is also declining. Therefore, reactive power compensation devices are more and more widely used. The power compensation device is used to suppl...
Three-phase lines are common: three-phase three wire, three-phase four wire The three - phase three - wire system is star connection neutral point ungrounded and Angle connection method, the general high - voltage power supply uses three - phase three - wire system, three - phase four - wire is star connection neutral point grounding, low - voltage system uses three - phase four - wire system. &nb...
Effect of Poor Power Factor The major effect of poor power factor is higher value of line current. We know that power factor (pf) is an important parameter for calculation of power in an AC circuit. For a given power and voltage, the current flowing through the line is inversely proportional to the power factor. This means that a poor power factor i.e. low power factor will result in hig...
3 phase load current imbalance In three phase systems, current unbalance is defined as the maximum deviation of any phase current from average divided by average current. Current unbalance can occur due to reasons within the control of the end user or outside the control of end user. Some of the reasons for current unbalance (or imbalance) are: Source voltage from the electric utility is unbalance...
Research background Because the value of harmonic loss is smaller than that of fundamental loss and the calculation is difficult, it is generally ignored in the theoretical calculation of line loss. However, with the development of power electronics technology, the nature of power generation and electrical equipment is becoming increasingly complex, and various nonlinear components put into ...
With the development of society and the increase of demand for electricity, Reactive power compensation technology has developed rapidly, including Static VAR Compensation and Dynamic Reactive Power compensation, and has gained rich operating experience. However, some problems have also been exposed in practice. Some reactive power compensation devices are inconvenient to move, and the equipment m...
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