Trends in active power line conditioners

Active power line conditioners, which are classified into shunt and series ones, have been studied with the focus on their practical installation in industrial power systems. In 1986, a combined system of a shunt active conditioner of rating 900 kVA and a shunt passive filter of rating 6600 kVA was practically installed to suppress the harmonics produced by a large capacity cycloconverter for steel mill drives. More than one hundred shunt active conditioners have been operating properly in Japan. The largest one is 20 mVA, which was developed for flicker compensation for an arc furnace with the help of a shunt passive filter of 20 mVA. In this paper, the term of 'active power line conditioners' would be used instead of that of 'active power filters' because active power line conditioners would cover a wider sense than active power filters. The primary intent of this paper is to present trends in active power line conditioners using PWM inverters, paying attention to practical applications.