Design and analysis of composite filter for power quality improvement of electric arc furnace

Electrical Arc Furnace (EAF) is one of the responsible cause for deteriorating power quality in the distribution network by, introducing harmonics, propagating voltage flicker and causing unbalance in voltages and currents. This paper presents design, analysis and simulation of composite filter for improving power quality of distribution network. The distribution network consists of non-linear load as an Electric arc furnace. Passive filters have been preferred for power quality improvement due to low cost, simplicity, reliability and control-less operation. At first passive filter has been designed to compensate current and voltage harmonics. The drawback associated with the passive filter is tried to solve by connecting a series active power filter along with the passive filter thus forming a composite filter. Performance of composite filter and passive filter is compared and analyzed to improve the power quality and at point of common coupling. The composite filter is consisting of a shunt LC passive filter connected with a lower rated voltage source PWM converter based series active power filter. Simulation for a typical distribution network with a composite power filter has been carried out to validate the performance. The simulations have been carried out in MATLAB environment using SIMULINK and power system block set toolboxes.