Optimal Design Of A UHF Broadband Antenna For PD Detection

Electric power equipment may produce partial discharge due to long time running and material aging, the UHF online detection which is of small size and high reliability has been extensively applied to power system. Two kinds of antennas for PD detection have been analyzed by simulation and experimental tested in this paper. They can respectively obtain an impedance bandwidth from 700 MHz to 3 GHz and 600 MHz to 1.5 GHz, which can effectively detect the PD signals and attenuate the signals below 300 MHz.The main contents of this thesis are as follows:1) The generating mechanism and development situation of PD detection is given. Basic principle and technology of Ultra-wideband antenna is introduced. And the simulation software is presented.2) Based on the ultra-wideband antenna principle and PD sensor size requirements for internal and circular observing window, by the Archimedean spiral antenna, an optimal dimension of UHF PD antenna is designed. The simulation analysis and test results show that it can obtain an impedance bandwidth from 700MHz to 3GHz. The antenna is fixed in reflective metallic shell to achieve unidirectional character and its gain up to 5 dBi.3) For the size requirements for external testing environment, by the logarithm antenna principle, a rectangular miniaturized UHF wideband Log-periodical antenna is designed. Through optimal simulation of antenna tooth structure, adding reflection shell, it could produce impedance bandwidth from 600MHz to 1.5 GHz. Its gain can come up to 3 dBi, it can effectively inhibit interference and available to detect the UHF PD signal.4) Advantages and disadvantages are analyzed about Archimedean spiral antenna and Log-periodical antenna in test results and application environment. Finally, the application and design of UHF antenna for PD are summarized and prospected.