摘要
变压器局部放电超声波定位法精度不高,主要原因是信噪比不高的超声信号到达两个传感器的精确时差很难获取。针对此问题,提出采用希尔伯特黄变换(HHT)对局放超声信号进行处理,以提取超声传感器接收到的超声波的精确时刻,从而求得精确时差。针对传感器接收到的超声信号的信噪比低,甚至局放超声信号被淹没在强烈的干扰信号之中的情况,提出了求取时差之前采用快速独立分量法(FastICA)对局放超声信号进行去噪处理。快速独立分量法无法对分离后的结果进行排序,需要从分离后的结果中提取出超声波信号,为此提出了包络线识别法,该方法对分离出的信号波形的上包络线进行采样,通过求取采样点的平均值来提取超声信号。算例结果证实了上述方法的实用性。
Aiming at the lower ultrasonic positioning accuracy of transformer partial discharge. The main reason is that it is difficult to obtain accurate time difference of the ultrasonic signals reaching two different sensors, especially when the signal-to-noise ratio is not high enough. To solve this problem, this paper applies Hilbert-Huang transform（HHT）in signal processing to extract the precise moment, and obtains the precise time difference easily. Because the signal-to-noise ratio（SNR） of received signal is low, and the PD signal is drowned in the strong interference signal, the paper uses the method named fast independent component analysis（FastICA）to denoise ultrasonic signal before obtaining the time difference.,which is not effective in separating the ultrasonic signal from the separated components.In order to solve the problem, the paper again propoes envelope identification methodwith which the upper envelope of the signal waveform is sampled and the average of the sampling points is calculated to extract the ultrasonic signal. The numerical results confirm the practicality of all the mentioned methods.
出处
《电测与仪表》
北大核心
2013年第12期69-72,共4页
Electrical Measurement & Instrumentation
