说明：  介绍了 Cohen类双线性时频分布并针对交叉干扰项影响无法完全消除的问题进行了重排时频变换以提取及分辨 含有白噪声和窄带周期干扰的局部放电信号。处理仿真和现场检测到的局部放电超声信号时根据白噪声和窄带 周期干扰信号在时域上的平稳性特性发现重排 Cohen类时频变换方法不仅可以很好地将局放信号和背景噪声以 及窄带周期干扰信号分辨开来,而且大大减弱并抑制了交叉干扰项的影响,保持了更高的时频分辨率和时频聚集 性,从而验证了重排 Cohen类时频变换方法的有效性。
(In order to express the partial discharge ( PD) information of gas insulated switchgear ( GIS) in time-frequency domain, weintroduced theCohen s class bilinear time-frequency distribution and its reassigned time-frequency transform method to pick up and distinguish theultrasonic signals in field from the whitenoises and narrow band periodic interference signals using the acousticemission ( AE) technology. After the processing of the simulated and PD ultrasonic signals in field, and according to the stationary feature of white noises and narrow band interference signals, wedraw a conclusion that the reassigned time-frequency distribution method can not only distinguish thePD signal from back ground noises and narrow band interference signals, but also decrease and restrain the influenceof cross-items, and acquire better time )