Research On Filtering Characteristics Of Double-tuned Filter

With the development of power electronics technology, more and more powerelectronic devices have been widely applied to the power system. However, itproduces very serious harmonic problems, has aroused great concern in thecommunity. Harmonic pollution has become one of the three hazards in the powersystem The other two hazards are electromagnetic interference and power factorreduced. Therefore, how to study suppression and governance the harmonic to ensurethe stable operation of the power quality and power system engineering has importantpractical significance. Passive filter has a large capacity, low price, many industrieshave adopted passive filters, the filtering aspect of our country is primarily based onpassive filtering based. With the development of HVDC technology, the double tunedfilter of passive filters becomes growing importance in power engineering.This paper studies the filtering performance of different structures of doubletuned filter. At first, it introduces the basic theoretical knowledge about double tunedfilter. Such as the current research situation at home and abroad, the arrived level oftechnology, the kinds, the structure, the feature of resistance frequency, the designprinciples, performance indicators and other basic parameters of calculationmethods,etc. Secondly，by the direct method and the practical engineering experienceto determine the parameters of the double-tuned filter’s six different structures, anduse six-pulse bridge rectifier as a harmonic source to build simulation models inPSCAD/EMTDC. Simulation content includes: before the filters were put into thesystem, the system-side’s current and voltage waveform and their spectrum; theharmonic voltage and current waveforms and their spectrum in secondary-side. At thesame time,simulate the system side and the10kV side of the fundamental current,5,the7harmonic current content.Beside that, inputs six different structures of doubletuned filter which in5,the7harmonic design, simulate the variation of voltage andcurrent waveforms, spectrum, and the harmonic current content. On this basis,according to the simulation results, through comparative analysis5-7times rates ofharmonic decline, the change of the voltage and current distortion rate for reference, explore the filtering performance of different structures’ double tuned filters.Based onthe simulation results to analyze and summarize in order to provide a reference forfurther research and engineering practice. Finally, according to the test cases of aharmonic converter station to analyze and evaluate.