变压器局部放电超高频在线监测天线研究

Research on fourth-order Hilbert fractal antenna for UHF online monitoring of partial discharge in power transformers

针对传统局部放电超高频检测天线频带窄、尺寸大的缺点,设计了一种用于在线监测变压器局部放电的多频带、尺寸小的超高频天线。通过研究了分形理论和天线测量原理,在现有四阶Hilbert分形曲线的技术基础上,利用Ansoft Designer电磁场仿真软件建立天线模型,并通过仿真计算,优化配置了天线的几何参数,设计制造了平板结构的四阶Hilbert分形局放超高频监测天线。利用设计的四阶Hilbert分形天线对四种典型油纸绝缘缺陷进行局部放电超高频信号监测,并采用文中设计的天线与现有技术的三阶Penao分形天线、三阶Hilbert分形天线在实验室进行局部放电对比测量,分析了天线实测效果,实验结果表明该天线能够有效应用于变压器局部放电超高频在线监测。

Ultra-High-Frequency(UHF) method for detection of partial discharge(PD) has been widely appreciated and studied. It can effectively avoid the low-frequency electromagnetic interference and has the advantage of high sensitivity. Mostly, the UHF antennas used for PD detection have large size, and the characters are narrow frequency pand, this paper designs a Hilbert fractal antenna with multi-frequency and small size for UHF PD online monitoring of transformer. In the existing basic principle of fourth-order Hilbert four-order fractal antenna technology, the planar antenna is modeled by Ansoft Designer. Based on simulation calculation, geometric parameters of the antenna were selected and the fourth order Hilbert fractal antenna was designed. The partial discharge UHF signal of four typical defects for oil-paper insulation was measured by the optimized fourth order Hilbert fractal antenna designed in the laboratory. Experimental results show that the designed antenna is qualified for online PD UHF monitoring.