电缆接头局部放电在线检测中的抗干扰研究

为实现强干扰环境下电力电缆接头有效的局部放电在线监测,研制了一种具有Rogowski线圈结构的宽频差动传感器并研究了小波分析方法对噪声的抑制性能。试验表明研制出的传感器对<1 MHz的窄带信号抑制比>50,灵敏度优于10pC;采用阈值法的小波分析可以有效提高测量信噪比。在此基础上开发了一套局部放电测量系统,该测量系统与传统的TE 571型局放仪的对比试验结果表明:所研制出的在线局放监测仪能够在高噪声环境下有效的检测到电缆接头的局部放电信号,并能够识别出导致放电的缺陷类型。

Study of Noise-reject Technique for PD Online Monitoring on Cable Joint

Noise rejection is the key technique for partial discharge online monitoring of cable joint,in order to detect partial discharge of power cable joint in heavy noise environment,an improved Rogowski-winding wideband differential sensor has been developed,and the noise-reject character of wavelet analysis was investigated.The study show that the improved Rogowski-winding wideband differential sensor has the Signal-to-Noise>2 and has a sensitivity better than 10 pC.And an online monitoring system was developed,the experimental results compared with the conventional PD detector of type TE 571 show that the test system adopted advanced Rogowski wideband differential sensor and noise-reject technique can acquire the PD signal in a heavy noise environment,the test system also can recognize the cable defects inducing the discharge.