| Summary: | 博士 === 國立臺灣科技大學 === 電機工程系 === 94 === This thesis presents a study on calculation and comparison of six power factor values by using a set of load data. It is intended to investigate the differences and effects of load characteristics on power factor values, and consequently to use this deviations to reflect the load characteristics of the inferior power quality. Within the six power factor value definitions discussed, three employing the IEEE Standard 1459-2000, and the rests are based only on fundamental components. First, the impacts of load characteristics to the power factor values are simulated based on the effects of harmonic distortion, load unbalance, and the load fluctuation. Then, the field measurement results of each representing user from the selected seven fields, such as railway, MRT, electric arc furnace, electrical and electronic plant, chemical plant, business building, and government office are examined. Additionally, the loading characteristics and power factor values of V-V, Scott, and Le Blanc connected transformers are also illustrated. At last, the examination also includes the searching of more sensible data compression techniques for the long-term monitoring of the load characteristics. Adopting the wavelet transform in conjunction with three coding methods to proceed the data compression, and then comparing the accuracy of power quantity calculation by using the reconstructed data. The comparison result reveals that the normalized embedded zero-tree wavelet coding has better performances on data compression. In order to benefit from a better power quality environment, a proper power factor definition and a more reasonable standard need to be used to truly reflect the loading characteristics of the power factor values.
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