Active Harmonics Filtering of Distributed AC System

Abstract

The tendency of connecting the Power Electronic loads and distributed power plants through Power Electronic converters is increasing day by day. These Power Electronic converters and loads are the sources of harmonics and reactive power which greatly affect the performance of the power system network. In a weak power grid, the voltage unbalance and non-sinusoidal regimes are very common. Under such circumstances not only the controllability of the power grid itself but also the controllability of the electronic connected to power system equipment’s is heavily affected. So, power quality of the modern power grid (smart grid) is an important issue to address. To overcome the problem of power quality, recent efforts have been made on active filtering. The active power filters have gained much more attention because of excellent performance to mitigate the harmonic and reactive power issues. But the performance of the active filters depends upon the control theory that is employed to formulate the control algorithm of the active filter. A shunt active power filter with controller based on Instantaneous active and reactive power (p-q) theory has been purposed to verify its performance and ability to compensate the harmonics and reactive power. The advantage of p-q theory is that it is instantaneous and works in time domain. The shunt active power filter connected to AC distribution system in the presence of different shares of Power Electronic loads is investigated. It has been investigated through simulations that even under unbalanced and distorted conditions of AC distribution supply voltage and unbalanced loading, shunt active filter is able to produce the unity power factor and mitigate the harmonics (THD) specified by power quality standards. Matlab/Simulink is used as a simulation tool for the research.