A Study On Harmonic Detection Motheds Of The Power Supply & Transmit Electricity System In Guangyuan District

This thesis is about studying the methods that application in the electric power supply system to detect the electric power harmonic in domestic and abroad. In this thesis, summarized the basic theories of Fourier transformation and the fast Fourier transformation that are generally adopted to detect and analyze the electric power harmonic in the electric power supply system. At the same time, summarized the even sample principle, the phenomenon of frequency mix, the window functions and the frequency leaking as so on, those are closely-related to sample from figure signal. Furthermore, we analyzed the investigating reports which were concerned the present situation of the electric power harmonic pollution in the Guangyuan district's electric power supply system, and presented the necessity and important of detecting and eliminating the electric power harmonic in the electric power supply system. The thesis's main contents including: Summarized the main reasons why the electric power supply system produce the electric power harmonic, and the electric power harmonic may bring what harms to electric power supply system's equipments and the other appliances which are connected in electric power supply system or the other electronic appliances beside the electric power supply system. Analyzed and explained the necessity and important that should detect and eliminate the electric power harmonic in the electric power supply system; Investigated and analyzed the no-line loads in Guangyuan district's electric power supply system. Analyzed and studied the situations of this electric power supply system and its examination reports that were done by Sichuan Province Electric Power Company in 1991, 2000. Summarized no-line loads and the present situations of the electric power harmonic pollution in the Guangyuan district's electric power supply system;Explained the theories of Fourier transformation and the fast Fourier transformation those are widely adopted by majority scholars to examine and analyze the electric power harmonic in the electric power supply system. Summarized the principle of even sample, the frequency mix phenomenon, the window functions and the frequency leaking as so on, those are closely -related to the figure signal. At the same time, summarized the basic principleto examine the electric power harmonic;Compared the methods those are based on five different principles, those methods are widely adopted by some scholars to examine the electric power harmonic in the electric power supply system. As the same time, pointed out the advantages and disadvantages of each method;Gave different methods those are applied in the three different kinds of the no-line loads in the Guangyuan district's specific electric power supply system to examine and eliminate the electric power harmonic.