HARMONIC STUDY OF VFDS AND FILTER DESIGN: A CASE STUDY FOR SUGAR INDUSTRY WITH COGENERATION

In majority of Sugar Industries, to achieve better efficiency of power, VFDs are extensively used. Initially D.C. Drives were used, but now these are slowly getting phased out and are replaced by A.C. Drives .In a case study of Harmonic Analysis of SAMARTH CO-OPERATIVE SUGAR FACTORY, ANKUSH NAGAR, MAHAKALA, JALNA it is commonly seen perception that, latest technology A.C. drives are having in built harmonic filters and hence do not produce harmonics / produce harmonics within prescribed tolerance limit. Because of variation in load pattern these drives still produce harmonics, which must be suppressed by using appropriate Harmonic Filter, otherwise it may result into malfunction of sensitive devices. It is more essential to suppress these harmonics, for SAMARTH CO-OPERATIVE SUGAR FACTORY, ANKUSH NAGAR, MAHAKALA, JALNA, as Sugar Industry has grid connected Cogeneration plant. The suggested method of filter design gives better result, reduces harmonic level (5th harmonics) to almost 10A from 154A. The values of load Kw, P.F., Voltage, current load inductance, capacitance, resistance are derived from average of readings actually available from site.