Performance Comparison of Sequence Extractors for Reference Current Generation and Sag/Swell Detection in Power Systems

Abstract

The electric power generation systems are relatively affected by unbalanced, fault voltages and harmonic distortions in single-phase or three-phase systems. These abnormal conditions cause power quality problems and have severe influences on control of power conversion systems. This paper presents a comparative benchmarking of positive-negative sequence (PNS) extractor methods for reference current generation, sag/swell detection without time delay and eliminating oscillations on control signals. The performance comparisons of the sequence extractor are examined in terms of harmonics, unbalanced networks and start-up. The selected PNS extractors are also applicable for control of single and three phase applications. The effectiveness and validation of the PNS extractors are examined in a power conditioner controller under various cases.