Wavelet transform based voltage quality improvement in smart grid

In the environment of today's smart grid scenario inclusion of renewable energy sources, power electronic devices, networked sensors and automated controls causes voltage sag and swell which affects power quality. This paper proposes a new method of sag and swell detection based on wavelet transform and its restoration. For good accuracy of system discrete wavelet transform (DWT) with multi resolution analysis (MRA) is used. Feature of input signal is extracted by selecting Daubechies wavelet (Db4) as mother wavelet. Advantages of Db4 wavelet compare to other wavelets are described. The simulation results for sag and swell restoration are presented. Block diagram, wiring diagram and hardware scheme of the developed model is explained.