| Gas Insulated Switchgear(GIS) is one of the most important switch equipment in the modern power system.The internal switch of GIS can operating correct or not determines whether the safe operation of the power grid can be. t present, the action of high voltage grade of GIS switch, most driven by hydraulic drive or compressed air, in order to ensure the normal operation of the hydraulic drive and the air compressor drive system, must start motor work pressure regularly, to confirm whether the system performance is reliable.However, due to equipment manufacturers, such as craft and improper installation process or operations for defects caused by equipment, air compressor damage, even cause driving at a slower pace or becoming failure accidents, threatening the stability of power grid operation, affect people’s life and production directly and cause serious social consequences.It is the key factor. GIS on-line internal PD monitoring has always been a hotspot in this research area.The antenna which has the virtues of broad band, high gain and small size can be used for ultrahigh frequency(UHF) partial discharge(PD) online detection in the gas insulated switchgear(GIS).In order meet the condition mentioned above, a kind of fourfold-band micro-strip monopole antenna was designed. The PD test comparison of micro-strip monopole antenna sensor and micro-strip patch sensor in GIS equipment which is in the laboratory.The main work and achievements are as follows.① By compositing different resonant frequency patchs to realize the multiband of microstripmonopole UHF antenna. It can effectively avoid the fixed interference or fixed narrowband interference which are existing in the application. Then the reasons for the multiband formation were discussed.② Based on the research of the realization of the multifrequency antenna and by using composite structure,increasing medium plate thickness,loading,the method of bending and folding and other technical means to widen the band and miniaturize the size of fourfold-band microstrip monopole UHF antenna.The four bands of designed antenna are: 282MHz~288.5MHz, 721.2MHz~764.2MHz, 891MHz~948.4MHz,1.211 GHz ~ 1.672 GHz. The radiation characteristics of the designed antenna are same as dipole antenna.③ By testing four typical insulation defects UHF PD in GIS to test the performance of antenna.The measured show that the design of the antenna has good bandwidth and full direction after processing and testing the antenna model and pass band appear in multiple frequency bands,the ability to receive signals of tne antenna is good.The detection results shown that multiband antenna broaden the total bandwidth and can receive more PD signals and has higher sensitivity and smaller size.So,it has obvious advantages compared to the single frequency microstrip antenna. |
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