Abstract—With the increasing of non-linear loads in electric power system, power quality distortion has become a serious issue in recent years. In paper and pulp industries, due to presence of concentrated high power non-linear loads such as electric drives, this problem is a greater concern. In this paper, the impacts of harmonic distortions on the electric drives in Delta paper mill, Vendra, West Godavari(Dist),Andhra Pradesh, India is investigated. The harmonic measurement is done with Fluke 434 power quality analyzer. Different solutions exist to reduce the harmonic emission of Adjustable Speed Drives in order to fulfill the requirements of the international harmonic standards. In recently active power filters gained an increased attention due to their effective harmonic reduction. In this paper an active power filter has been designed for minimization of the harmonics, which is implemented in matlab/simulink based on real time measurement of the harmonic data. Index Terms— Variable Speed Drives, Harmonics, Delta Paper Mill (DPM), Power Quality, power quality analyzer, minimization of harmonics and active power filter I. INTRODUCTION N modern power systems, due to increase of non-linear loads, power quality has become a great concern. Non- linear loads, which were only 15% of total loads in 1987, have increased to 50% in 2000[1,2,8,9]. In the paper industry, the main production line needs high quality electric power because it consists of several coupled motors working simultaneously together with precise speed. These power quality disturbances cause paper breaks that require a long time to clean the machinery and resume production. They may also blow the rectifier fuses in the DC drives because of higher transient current [1-3]. In the Delta paper mill plant, there are 15 DC drives on the paper machine working together. Tripping the paper machine, usually, causes other areas of the paper mill such as wood handling Manuscript received September 21, 2011; revised November 20, 2011. Y.Kusumalatha is with Dept of Electrical and Electronics Engg, Lakireddy Balireddy College of Engineering(Autonomous), Mylavaram, A.P,India (e-mail: kusumalathay@gmail.com) Ch.Saibabu is with Dept of Electrical Engineering, University College of Engineering (Autonomous), JNTUK, Kakinada, A.P,India (e-mail: chs_eee@yahoo.co.in). Y.P.Obulesu is with Dept of Electrical and Electronics Engg, Lakireddy Balireddy College of Engineering(Autonomous), Mylavaram, A.P,India (e- mail:ypobulesh@gmail.com).ph:+919966747042 and pulp preparation to stop [4]. The latest investigations show that the cost of poor power quality for industry is about $US12 billion per year [5,6]. The transient voltage variations are caused by lightning strikes, switching of power lines and capacitor banks, system faults, and large motor start-ups. Therefore, a good power quality monitoring system is essential for the paper mills in order to decrease the downtime and increase the efficiency. Although, electric drives are sensitive to voltage distortions, they are also one of the major sources of current harmonics generation and power quality problems [9]. Electric drives draw non sinusoidal currents from the electrical power system[10,11]. The current harmonics passing through the impedance of the power system create non-linear voltage drops and cause voltage distortions. Therefore, the input voltage provided to the distribution transformers is not pure sinusoidal. One of the major effects of harmonic distortions is increasing transformer losses. In presence of harmonics, the load loss, eddy current loss, and other stray losses are increased. Possible problems include transformer overheating, motor failures, fuse blowing, capacitor failures, and mal-operation of controls [12]. In addition, they increase the hot spot temperature of the transformer which results in loss of life. Furthermore, if voltage harmonics level is more than standard, audio noise and no load loss will also be increased in transformers. In this paper, the impacts of harmonic distortions on the electric drives in Delta paper mill, Vendra, West Godavari(Dist), Andhra Pradesh, India, which is major supplier of different kinds of paper to most of the industries/organizations in south India, is investigated. The harmonic measurement is done with Fluke 434 power quality analyzer. A large diversity of solutions exists to reduce the harmonic emission of Adjustable Speed Drives in order to fulfill the requirements of the international harmonic standards. In recently active power filters gained an increased attention due to their good harmonic reduction. In this paper an active power filter has been designed for minimization of the harmonics and results are presented in terms of % THD without and with active power filter, which is implemented in Matlab/Simulink based on real time measurement of the harmonic data. Minimization of Harmonic Distortion of Industrial Motor Drives with Active Power Filter in Paper Mill - a Case Study Y.Kusumalatha, Ch.Saibabu, and Y.P.Obulesu I Proceedings of the International MultiConference of Engineers and Computer Scientists 2012 Vol II, IMECS 2012, March 14 - 16, 2012, Hong Kong ISBN: 978-988-19251-9-0 ISSN: 2078-0958 (Print); ISSN: 2078-0966 (Online) IMECS 2012