局部放电检测高增益柔性馈电立体螺旋天线的设计与应用

Design and Application of High-gain Steric Helical Antenna With Flexible Feeding Network for Partial Discharge Detection

局部放电(partial discharge,PD)检测天线在检测方向上应保持高增益,以改善灵敏度和信噪比。由于适配的功分网络截面积大,因此高增益立体螺旋天线尚未运用于局部放电检测领域。以单臂螺旋天线和四臂螺旋天线作为研究对象,通过仿真确定天线优化区间,并以带宽、增益作为目标,基于粒子群优化算法优化结构参数,以提高检测灵敏度,保持定向高增益;设计适配的柔性功分馈电网络,以减小天线体积、提高信噪比;通过局放测试检验设计的高增益立体螺旋天线的性能,并与商用平面等角螺旋天线比较。研究结果表明:优化后的单臂螺旋天线具有多频段检测特点,结构简单,占用空间小;通过柔性功分网络加载的四臂螺旋天线在0.5~2.0GHz频段的增益均>5.0 dB,主谐振点1.02 GHz处的增益达到了6.37 dB,整体横截面直径缩小至60 mm,测试信噪比优于平面等角螺旋天线。与传统局放检测天线相比,设计的高增益柔性馈电立体螺旋天线能在特高频范围的低频段保持高增益,并在各谐振频率保持轴向检测特性。

The antenna applied for partial discharge detection should maintain high gain in the detection direction,so as to improve the sensitivity to the discharge signals and the signal-to-noise ratio.Due to the large cross-section of power divider,the high-gain steric helical antenna has not been used for partial discharge detection.Single-arm helical antenna and quadrifilar helix antenna were taken as research objects.The antenna structures were simulated by sweep simulation to determine the optimization range,and were further optimized with bandwidth and gain based on the particle swarm optimization algorithm,in order to improve the detection sensitivity and maintain high gain.Appropriative power division network for the quadrifilar helix antenna was invented to minimize volume and improve signal-to-noise ratio.The performance of two antennas were examined through discharge tests,which was compared with commercial helical antennas.The results indicate that the optimized single-arm helical antenna has the advantages of simple structure,small occupied space and multi-frequency narrowband detection.The gain of quadrifilar helical antenna attached by power division network is greater than 5.0 dB in the frequency range of 0.5 GHz to 2.0 GHz,and reaches 6.37 dB at the main resonance point of 1.02 GHz,whose diameter is reduced to 60 mm.The signal-to-noise ratio of quadrifilar helix antenna is superior to that of the commercial planar equiangular helical antenna.Compared with traditional helical antennas,the two antennas keep high gain in lower frequency band and retain axial detection characteristics at each resonance frequency.