【摘要】 由于强烈的窄带周期干扰、白噪声和脉冲干扰等外部干扰,变压器局部放电在线监测技术中的局部放电信号提取一直是个难题。应用小波去噪技术研究了局部放电在线监测中的噪声抑制方法,对母小波及阈值(threshold)的自动选择方法进行了深入研究。仿真信号和现场实测信号分析表明,该方法适于变压器局部放电在线监测中的白噪声抑制,而对周期窄带干扰的抑制效果相对较差,需与其它对窄带周期干扰抑制效果较好的数字滤波方法结合,将具有良好的实际应用效果。更多还原

【Abstract】 Because of the strong interferences, such as discrete spectrum interferences (DSI), white noise and pulse-shaped interferences, it is still a difficult work to extract the partial discharge (PD) signal for transformer online monitoring techniques. Through deeply study on the automatic selection of threshold value and mother wavelet, the wavelet-based de-noising method for partial discharge signals is proposed. The analyzing results on simulation signal and field-measured signal indicate that the proposed method is fit for de-noising white noise but for DSI the comparably worse de-noising results is acquired. Hence it is predicted that good de-noising results will be achieved with the wavelet-based de-noising method combined with digital filtering method fitting for de-noising DSI.更多还原