Power Quality Transient Signal Test And Research Of Harmonic Source Identification

Power Quality (PQ) research is an important leading edge in the powersystem. By the development of modem technology, factors of power qualityproblems are increased. For example, using non-linear loads such as powerelectric devices, and start and stop of large electric equipment load to a resultthat the problems become much more serious. For some reasons, China isespecially lagging behind in reliability and stability of power system voltageindex. Therefore, how to enhance and ensure power quality is becoming animperious task in the field of the world electrical area.In present thesis, the classification and feature description of the most ofdisturbance waveforms are introduced and analyzed. One of the mostimportant issues in PQ problems is how to detect and classify disturbancewaveforms automatically in an efficient manner, which is the basis of PQtransient disturbance monitoring arithmetic and auto-classification. Dyadicwavelet transform, multi-resolution analysis and power mutation analysis areused to investigate kinds of transient power quality disturbance signal. Amethod is designed based on dyadic wavelet transform, which is to examinepower quality signal such as impulsive, oscillatory, sag, swell and notchwaveforms and auto-classify these kinds of disturbances. Through theacademic resource and data test, this method proves a good result in practice.Presently, technology research is doing all over the world to develop aproved method which is more reliable in abroad areas for harmonic sourcelocation to solve the problem of power quality responsibility determination.In this paper, these problems are discussed. Influence of power system byharmonic source and loads of different characteristics are discussed in thepaper. Some technology theories on harmonic source recognition areparticularized especially the application of harmonic flow calculation andharmonic power direction method. The applicability of harmonic powerdirection method under different system parameters is derived and thecorrelated aspects that affect the reliability and application condition ofharmonic power direction are summarized.