Detection and Localization of Power Quality Disturbances Using Space Vector Wavelet Transform: A New Three Phase Approach

This paper presents a new three phase approach based on space vector discrete wavelet transform to detect and localize power quality disturbances (PQD). This approach provides high resolution time frequency representation used to detect and localize the disturbances. Supplementary information about detected disturbances (duration and frequency spectrum) extracted in order to characterize them. From the monitored three phase voltage signals a space vector is generated using Clarke Transformation. For normal system voltage the space vector is of constant magnitude signal of 1.5pu. If PQD occurs in any one or all phases of system, results in change of magnitude or frequency or both of the space vector. The space vector is decomposed using Discrete Wavelet Transform (DWT) and the magnitude of detail coefficients is used to detect and localize the PQ disturbances. The proposed technique monitors all three phase voltages simultaneously therefore can offer fast detection than existing single phase based techniques. A practical power system network is used to validate the proposed technique. Keywords—space vector, discrete wavelet transform, multiresolution signal decomposition, Clarke transform, power quality disturbance, wavelet coefficients