Author : Goutam Kumar Malla and A. Ramulu

The application of power electronics devices such as arc furnaces, adjustable speed drives, computer power supplies etc. are some typical non-linear characteristic loads used in most of the industrial applications and are increasing rapidly due to technical improvements of semiconductor devices, digital controller and flexibility in controlling the power usage. The use of the above power electronic devices in power distribution system gives rise to harmonics and reactive power disturbances. The harmonics and reactive power cause a number of undesirable effects like heating, equipment damage and Electromagnetic Interference effects in the power system. The conventional method to mitigate the harmonics and reactive power compensation is by using passive LC filters but this method has drawbacks like large size, resonance problem and fixed compensation behaviour etc., so this solution becomes in effective. Subsequently, the active power filter (APF) comes in to the picture, which gives promising solution to compensate for the above adverse effects of harmonics and reactive power simultaneously by using suitable control algorithms.

Key words: Active Power Filters (APF), Shunt Active Power Filter (SHF), Series Active Power Filter (SRF), Unified Power Quality Conditioner (UPQC),Voltage Source Inverter(VSI).

Article published in International Journal of Current Engineering and Technology, Vol.5, No.1 (Feb-2015)