Power Factor Correction andActive Filtering TechnologyApplication forIndustrial Power Systems withNon-linearLoads

Powerfactor andharmonics problemin industrial powersystems withnon-linear loads ispresented. Traditional andmodernadvanced technologies forpower factor improvement andharmonic mitigation arereviewed. Advantages ofpowerelectronics basedstatic reactive power compensation (STATCOM)andactive harmonic filtering areshown.Design issues forpowerelectronics converter operating as STATCOM&activefilter are discussed. Modeling andexperiment results arepresented forboth advanced technologies. I.INTRODUCTION There hasalways beenapowerfactor andharmonics problem inindustrial powersystems withnon-linear loads(1). Oneoftheexamples issteel-making where high-power arc-furnaces andvariable speed electric drive (rolling mills, fans) areutilized. Pulsed reactive power flowatfundamental frequency andsevere voltage and current harmonics significantly reduce powerquality of thesystem. Theformer oneisduetothepulsed nature of theloadoperation anditspowerfactor. Itisnon- sinusoidal loadcurrent that accounts forthelatter. Fast variations ofthereactive poweralsoleadtothebus voltage variations, sagsandother harmful disturbances. It influences heavily thedesign oftheplant powersystem. Non-sinusoidal loadcurrent accounts forbusvoltage harmonics. The presence of voltage and current harmonics inpowersystemcutsdownload-life of electrical equipment suchas,forexample, transformers andpowerfactor correction capacitors. Itisalso responsible in some way forfaults in control, communication andautomation plant systems. Moreover, nowadays powersystems becomemoreandmore integrated andmutually dependent duetoliberalization of energy market. Therefore, powerquality problem ofa particular plant ismorelikely tohaveadeepimpact on thewhole powersystem performance. Thetraditional wayofpowerfactor improvement and harmonics mitigation atsteel-making plant isutilization ofthyristor-based static varcompensators combined with harmonic filters (2,3). Shunt thyristor-contro lled reactors