In recent years there has been considerable interest in the development and applications of active power filters because of the increasing concern overpower quality, at both distribution and consumer levels. Active power filter and passive filters (APF and PF) are the traditional ways of compensating for harmonics. Active filtering of electric power has now become a mature technology for harmonic compensation. However, both of the two ways have some disadvantages, namely resonance and tuning problems in passive filters, and capacity, rating, initial and running cost in active power filter. As a result, various hybrid filter topologies have been developed which combine the advantages of both passive and active filters. The Hybrid power filter is consisting of a passive filter connected in with an active power filter. In this book, power quality improvement based on hybrid power filter is analyzed for a non-linear RL-load connected to a three-phase ac supply which can improve the power quality.