摘要
基于PD信号的复小波变换模极大值随尺度s的增加而增加,而白噪声的复小波变换模极大值随尺度s的增加而减小的特点,创建一种分层复阈值算法。将分层复阈值用于复小波变换对仿真PD信号的去噪,并与全局复阈值算法进行了比较。同时在对仿真PD信号去噪后的波形畸变研究中,为弥补波形相似性参数(NCC)的不足,提出一个新的描述波形相似程度参数——变化趋势参数(VTP),并结合去噪前后的信噪比(SNR)对去噪效果进行综合评价。将分层复阈值技术用于对实验室实测的模拟GIS超高频PD信号的去噪。结果表明,采用分层复阈值技术的复小波变换抑制白噪声的效果更好,在高信噪比(SNR)或噪声抑制比(NRR)的情况下,对信号的畸变也更小。
According to the characteristic of modulus maximum of partial discharge（PD） signal and white-noise, an algorithm of complex multilevel threshold is put forward. The de-noising effect of complex multilevel threshold is compared with the effect of complex globe threshold. In order to make up the shortage of NCC, a new parameter--variational trend parameter（VTP） is put forward, which describes the degree of waveforms＇ similarity. The de-noising effect can be synthetically evaluated by VTP, NCC and SNR. Finally, complex multilevel threshold is used to suppress the white-noise in ultrahigh frequency PD signal which is got from stimulant GIS in lab. The findings indicate that this threshold can suppress white-noise effectively with small distortion of PD signal.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2007年第21期25-30,共6页
Proceedings of the CSEE
基金
国家自然科学基金项目(50577069)。~~
关键词
局部放电
复小波
变化趋势参数
分层复阈值
白噪干扰
partial discharge
complex wavelet
variational trend parameter
complex multilevel threshold
white-noise
