中文摘要：

针对电晕放电远距离检测的需求,基于窄带测试原理设计了一种窄带测试系统。该系统主要由接收前端和处理终端组成。接收前端中,设计了定向性强、增益≥9 dB的螺旋天线作为接收天线,利用差分放大单元增强电晕放电信号。数据处理终端中,设计了虚拟仪器代替常规测试系统中示波器和频谱仪,设计了全相位数字滤波器以实现强背景干扰下放电信号的快速降噪和特征提取。对模拟电晕放电信号的测试结果表明：实验区域背景噪声主要分布在400 MHz以内,采用80 MHz～2 GHz的宽带测试系统最大测试距离为100 m,而使用所设计的200～300 MHz窄带测试系统最大测试距离可达260 m。所设计的窄带测试系统抗干扰能力强,测试距离远,为电晕放电远距离测试提供参考手段。

英文摘要：

Aiming at remote detection of corona discharge, we designed a narrow-band test system based on the nar- row-band testing theory. The system comprises a signal receiver section and a processing terminal section. In the receiver section, we designed two helical antennas which had good directionality and a high gain over 9 dB as the receiving an- tenna, and a differential amplification unit to magnify the received corona discharge signals. In the processing terminal section, we designed virtual instruments to replace conventional instruments such as oscilloscopes and spectrum analyzers in order to achieve convenient signal processing, as well as an all-phase digital filter for noise cancellation and discharge signal feature extraction in backgrounds with strong interference. According to the results from tests of corona discharge signals, generally the background noise has a spectrum within 400 MHz, and the proposed narrow-band test system with a bandwidth from 200 MHz to 300 MHz has detection distance up to 260 m, which is a significant improvement compared to traditional broadband test system with bandwidth from 80 MHz to 2 GHz, which has the largest detection distance of 100 m. The results verify that the designed narrow-band test system has high anti-interference capability and long detec- tion distance, and hence it is quite promising for remote detection of corona discharge.