HARMONIC-ANALYSIS OF INDUSTRIAL-POWER

When large harmonic producing loads are added to an industrial plant p ower system it is good engineering practice to analyze the impact on t he power system by performing harmonicmodeling analysis of the system at the design stage, Such a study can identify any potentially harmful resonances or other harmonic levels that are-predicted to be in exces s of IEEE 519 recommended limits and suggest corrective measures (if n ecessary). This paper discusses the Impact of the harmonic limits of I EEE 519-1992 on the industrial power consumer and addresses the differ ences between the 1992 and 1981 versions of the standard, Harmonics pr oduced by variable frequency drives are discussed. The data required t o conduct a harmonic study, the types of analyses that can be performe d, and some of the mitigating measures that can be taken to alleviate a potential harmonic problem are detailed. A case study is presented b ased on a typical paper mill where a large variable frequency drive wa s added to the power system.