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In power system, the voltage pulsation and deficiency or surplus of reactive power will have a great effect on the quality of electric power supply. Dynamicly local reactive power compensation is one of the best methods to reduce the power network loss and improve the efficiency of transmission and distribution. Through the effective methods of compensation, we can keep the balance of reactive power...
Dynamic Voltage Restorer (DVR) restores the distribution system load voltage to a nominal balanced sinusoidal voltage, when the source voltage has distortions, sag/swell and unbalances. DVR has to inject required amount of Volt-Amperes (VA) into the system in order to maintain a nominal balanced sinusoidal voltage at the load. A new control technique is applied to compensate the sag and harmonics...
This paper presents and compares the performance of two controllers namely Fuzzy Logic and Proportional Integral applied to a voltage source inverter/converter operating as an active power filter. The active power filter is operated to compensate harmonics and reactive power generated by the non-linear load and power factor correction simultaneously. This work is performed in order to make an accurate...
Dynamic Voltage Restorer (DVR) restores the distribution system load voltage to a nominal balanced sinusoidal voltage, when the source voltage has distortions, sag/swell and unbalances. DVR has to inject required amount of Volt-Amperes (VA) into the system in order to maintain a nominal balanced sinusoidal voltage at the load. A new control technique is applied to compensate the sag with phase jumps...
This paper presents analysis of time-ratio-controlled autotransformer as a mitigating device for voltage sag disturbance. Control circuit based on load RMS and voltage sag sensing circuit based on peak detection are employed. Commonly dynamic voltage restorer and STATCOM are employed for mitigation of voltage sag. The proposed system has less number of switching devices in comparison to commonly used...
Through analyzing the typical systempsilas characteristic and Ultra-High Voltage(UHV) ac transmission linepsilas characteristic, the strategy by controllable shunt reactor is presented to improve transmission quality in electric networks in this paper. By using MATLAB PSB, simulation model of UHV ac transmission line from Jindongnan to Jingmen was built to study control effects on frequency over voltage,...
The conventional methods used in the isolation of the UPQC are add a isolation transformer in the point, in which series unit or parallel connection unit access the system, but owing to the non-linear of the transformer, this isolation method shall bring many baleful ingredients. In order to avoid the baleful influence of the conventional isolation transformer, the text introduces a sort of new-style...
This paper presents a novel DC link voltage feedforward control to improve the electric drive system tolerance capability to the dc link voltage sag. A uniform mathematic model, comprising the battery packs, voltage source inverter (VSI), permanent magnet synchronous motor (PMSM) is built up in the d-q rotating coordinates rather in three-phase stationary coordinates. In order to study the influence...
A method of the thyristor rapid switched capacitors is presented in this paper, which breaks through the bondage of the conventional methods. In addition, a novel algorithm of two time reactive power has been presented, with which reactive power can be calculated fast. Meanwhile, with microcomputer synchronous phase lock technology, quick switching without transition can be realized, dynamic reactive...
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