Because of increasing requirements of the present consumers and industrial units utilizing sensitive loads, there is need of good power quality in order to retain the power quality standards. Nowadays the study of the voltage flicker is b ecoming essential part of power quality studies. The flicker is typically the effect of a rapidly changing load which is large with respect to the short circuit ab ility of an electrical supply system. The inferior effects of voltage flicker include malfunctioning of power electron ic equipment. Also it causes annoying effects to human. Hence detection of the flicker source is an essential step in the power quality assessment process. This paper delivers a review ab out methods used to identify flicker producing loads in accordance with IEC 61000-4-15. Once the report related to the disturb ance place is known, an investigation and corrective action can b e accordingly carried out. Also a method b ased upon Discrete Wavelet Transform and Artificial Neural Network is proposed to detect initial instance of occurrence of flicker.

Because of increasing requirements of the present consumers and industrial units utilizing

Day by day the increment in non-linear load has deteriorated the VoltageQuality of power supply system. The crucial concerns originated are VoltageSag and Voltage Harmonics. These power quality problems cause a lot oflosses in the power system which results in commercial losses as well. Themoderation of these issues within the permissible limits is much needed.Among, the several methods and devices that exist, the Dynamic VoltageRestorers (DVR) are often used. This paper focuses on mitigation of Volt-age Sag and Voltage Harmonics. In the development phase of DVR, thedesign of controller is an important phase to be considered. The nonlinearcontrol approach of design is superior to linear control. In this paper theTerminal Sliding Mode Control is used for designing the controller for DVR.To improve accuracy and robustness, an additional nonlinear quantity hasbeen introduced to the equation of traditional Sliding Mode control. TheDynamic Voltage Restorer is modelled using MATLAB/Simulink and used for studies. The simulation results presented validates effectiveness of theproposed control approach.