Symmetrical components-based modified technique for power-quality disturbances detection and classification

This paper presents a modified approach based on symmetrical components in time domain for the detection and classification of various power-quality (PQ) disturbances. Single-phase PQ disturbance signal along with the two other ideal phases generated using phase-locked loop (PLL) is processed to find out the symmetrical components of all phases in time domain. Triggering points for PQ disturbances have been detected from the negative-sequence component of disturbance phase and have been easily classified from the signatures of the waveforms using the summation of the positive- and negative-sequence components. PQ disturbances, such as voltage sag, swell, interruption, harmonics, flicker, transients, notches, and spike present in a distribution system, have been investigated and are easily localized and segmented with this technique. Being a time-domain technique, it can be adopted for the online monitoring and assessment of the PQ disturbances. Simulated and real-time results are presented for a number of PQ disturbances to show the effectiveness of the proposed method for the PQ disturbances detection and classification