Analog Implementation and Real-Time Testing of a DWT-Operated DVR System

This paper presents an implementation and experimental testing of the discrete wavelet transform (DWT) using passive LC filters for operating a dynamic voltage restorer (DVR) system. The proposed DVR operating strategy is based on designing Butterworth passive LC filters with cut-off frequencies that are identical to cut-off frequencies of DWT associated digital filters. These passive LC filters can detect abnormal conditions that may disrupt the quality of the power supplied to sensitive loads in a power system. Detecting any abnormal condition is realized through extracting high and low frequency components present in system voltages using high-pass and low-pass filters, respectively. The designed Butterworth passive LC passive filters are third order systems to simplify their practical implementation as well as their integration with the test power system and the DVR. The proposed passive LC filters are implemented and tested to operate a DVR system for improving the power quality under different abnormal conditions. Simulation results for transient voltage dip and steady-state harmonic distortion cases show significant performance of the DVR system operated by the designed Butterworth passive LC filters.