特高频传感器结构参数对其幅频特性的影响

Impact of Structural Parameters of UHF Sensors on its Amplitude-Frequency Response Characteristics

传感器是变压器特高频局放检测中的关键设备之一,阿基米德螺旋天线和平面等角螺旋天线是目前常用的特高频传感器,采用扫频法在吉赫横电磁波室内测量了一系列结构参数不同的这两种螺旋天线的幅频特性,并在空旷场地测量了它们的驻波比。测试结果表明:天线内外径尺寸对其幅频特性的影响比较明显;测试天线的驻波比小于2,能满足工程测试的要求;变压器局放检测应选用宽频带特高频传感器;平面等角螺旋天线适合应用于局放检测,阿基米德螺旋天线适合用于局放时延定位研究。

In the detection of ultra-high-frequency （UHF） partial discharge （PD） in power transformer, sensor is one of the key equipments. At present, Archimedean planar spiral antenna and plane spiral equalangular antenna are commonly used UHF sensors. By use of frequency sweep method, the frequency-amplitude response characteristics of these two kinds of antennas with a series of different structural parameters are measured in gigahertz transverse electromagnetic （GTEM） cell, and their standing wave ratios （SWRs） are also measured in open space. Measurement results show that inside and outside diameters of these antennas impact their frequency-amplitude response characteristics evidently; when the SWR of measuring antenna is smaller than 2, the requirement of practical measurement can be satisfied; to detect PD in power transformer, wide frequency band UHF sensor should be chosen; plane spiral equal-angular antenna is suitable for PD detection; Arcinmedean planar spiral antenna is suitable for time-delay location of partial discharge.