Minitype Quasi-TEM Horn Antenna for Partial Discharge Detection in GIS

An outer-positioned small quasi-TEM horn antenna sensor was designed and constructed for detecting the partial discharge in gas insulation substations(GIS),which could expediently receive the electromagnetic wave leaked from the basin-type insulator,and effectively suppress low frequency electromagnetic interference from surroundings.Certain effective structures such as dielectric filled horn,wedge-shaped substrate and backing cavity were utilized to miniaturize during the antenna design process so as to optimize standing-wave ratio characteristics.The model calculation and experimental data measured in the laboratory shows that the antenna possesses a good radiating performance and a multi-band property when working in the ultrahigh frequency(UHF) band.The partial discharge was tested in the device of imitation GIS defect,detected by TEM horn antenna and existing microstrip patch antenna concurrently,then,the measurement results were compared.