Abstract:
Voltage sag and swell is one of the common Power quality problems in Ethiopian Distribution
system. The same problem is occurring in Arbaminch Distribution system abruptly. Due to this
sensitive electronics equipment‟s are burning in Arbaminch frequently. While measuring the
voltages in Arbaminch Distribution mainly in Secha feeder 55% sag and 45% swell has been
recorded. One of the solutions to the aforementioned issue is the dynamic voltage restorer
(DVR). DVR is the most practical and cost-effective options for reducing voltage sag and swell.
Fuzzy Logic is used to control the DVR quickly, and two modes of operation for controlling
voltage sag and swell are used to control the AC/AC converter. When grid power enters at a
voltage that is less than to 220Vr.m.s, a voltage sag mode takes place, and when it enters at a
voltage that is higher than to 220Vr.m.s, a voltage swell mode takes place. The sag is improved
near to 96% and swell is also improved near to 96% by the DVR controlled with fuzzy logic
controller. The whole simulation is carried out in MATLAB/Simulink.
