基于小波变换和维纳滤波技术的小电流接地系统单相接地故障选线研究

STUDY ON FAULTY LINE DETECTION OF SINGLE PHASE TO GROUND FAULT IN MALL CURRENT NEUTRAL GROUNDING SYSTEM BASED ON WAVELET TRANSFORM AND WIENER FILTER TECHNOLOGY

作者综合应用小波变换理论和维纳滤波技术,提出了一种小电流接地系统单相接地故障选线的新方法。该方法对故障发生后的零序电流信号进行小波变换,通过维纳滤波对小波系数进行滤波去除噪声,并利用去噪后的信息进行选线。该方法能够有效地从被噪声干扰的信号中得到有用信息,克服了故障信号信噪比低的缺点,并能够充分利用故障信息连续判断。应用现场实际故障数据对该方法进行的验证表明,该方法能够满足实用要求。

Integrating the wavelet transform theory with Wiener filtering technology, a new faulty line detection method for single phase to ground fault occurred in small current neutral grounding system is proposed, in which the wavelet transform is applied to zero sequence current signal after the fault occurred and by means of Wiener filter the noise in wavelet coefficient is removed, then the fault line detection is conducted by use of the noise-removed information. The proposed method can effectively derive useful information from the signal with noise interference and overcome the disadvantage of low signal-to-noise ratio, in addition, the continuous judgment of fault information can be realized. The results of the verification of proposed method by on-site actual fault data show that the proposed method is practicable.