Title page for etd-0801112-212357


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URN etd-0801112-212357
Author Yu-Jen Hsu
Author's Email Address hyj6168@cht.com.tw
Statistics This thesis had been viewed 5356 times. Download 2623 times.
Department Electrical Engineering
Year 2011
Semester 2
Degree Ph.D.
Type of Document
Language zh-TW.Big5 Chinese
Title Voltage Flicker Analyses and Predictions
Date of Defense 2012-06-07
Page Count 127
Keyword
  • Flicker
  • Electric arc furnace
  • Lyapunov exponent
  • Phase space
  • Flicker transfer factor
  • Abstract Voltage (lighting) flicker is mainly caused by the electric arc furnaces (EAF) facility supplied by the medium and high voltage power network. In addition to that, because of the increase of wind power generation in both quantity and capacity, intermittent power output of wind turbines under wind speed variation could also cause voltage flickers that affect the performance of lighting and electronics devices in the neighboring feeder buses. Successful voltage flicker prediction and propagation estimation would help both utility and customers in dealing with the problem. This dissertation presents a nonlinear model for the short term prediction of voltage flicker due to EAF operations.
    In this study, synchronized voltage flicker measurement was conducted at several EAF facilities to understand the stochastic behavior of voltage flicker. The electric loading condition during EAF melting process shows a long term qualitative behavior of a dynamic system and illustrates a special structure of a fractal system. With the fractal structure identification, the behavior hidden behind the voltage flicker time series measurement could be grasped. Using a phase space reconstruction technique and Lyapunov exponent (LE) of state trajectory in the phase space, based on actual voltage flicker measurements, it is proved that the voltage flicker time series is chaos. By using LE, three formulations are adopted to build the prediction models and illustrate the feasibility of short term EAF voltage flicker prediction.
    Currently, some Asian countries are using the Japanese ΔV10 flicker voltage standard. Due to the adoption of IEC standard by IEEE and European countries, a rational conversion of flicker planning limits between different standards would help utilities consider revising or changing their voltage flicker standards and planning limits. Statistical analyses of Pst and ΔV10 measurement are conducted in this study. Under different EAF types and operation conditions, reasonable conversion factors between Pst and ΔV10 standards are derived, and the flicker transfer factor between different voltage levels of the power supply system are presented.
    Advisory Committee
  • Ching-Tsai Pan - chair
  • Chih-Wen Liu - co-chair
  • Wen-Kung Chang - co-chair
  • Shi-Lin Chen - co-chair
  • Jiann-Fuh Chen - co-chair
  • Chan-Nan Lu - advisor
  • Files
  • etd-0801112-212357.pdf
  • Indicate in-campus at 0 year and off-campus access at 3 year.
    Date of Submission 2012-08-01

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