Transfer function approach to a passive harmonic filter design for industrial process application

This paper presents an analytical design method of a passive harmonic filter for industrial process application and uses a new transfer function approach in the analysis and design. The transfer function approach derives an analytical formulation of a utility system including passive filters with a basis of Laplace transform. In addition, it provides a graphical formulation so that a visualized insight into an interaction between individual filter and system response can be attainted. Harmonic impedance, voltage division and current division transfer function are used as a design tool, which makes calculated filter parameters to satisfy IEEE-519 requirements. A simple six-step design procedure is introduced in the filter design and the procedure consists of measurement and analysis on system, selection of filter location(PCC), calculation of filter specification, decision of tuning order, filter design for system and fit filter to system. Philosophy governing the design procedure is based on a numerical/ graphical iterative solution as well as trial and error with visualization feed-back using “algebra on the graph”. Finally, performance of the designed passive harmonic filter is verified by experiment and it shows that 5th, 7th, 11th and 13th harmonics are decreased within IEEE-519 requirements, respectively.