Proper selection of passive and active power quality filters for the mitigation of mains harmonics

The steady increase in non-linear loads on the power supply network such as, for instance, variable speed motor drives (VSDs), raises questions about power quality and reliability. In this respect, a great deal of attention has been focused on harmonics as they overload the network infrastructure, cause reliability problems on equipment and system level, and waste energy. Passive and active harmonic filters are used to keep these harmonic problems in check. The use of both active and passive technology is justified. The difficulty is in how to select and deploy harmonic filters correctly, which is key to achieving a satisfactory performance. This paper explains which specifications are suitable when it comes to choosing active and passive harmonic filters and which mistakes need to be avoided. Andrzej Pietkiewicz, Ph.D., Project Manager Innovation Center Stefan Melly, Business Development Manager