摘要
采用时域反射法对高压电缆局部放电源进行定位中,需根据局部放电信号的直接信号与反射信号的时间差估算放电源位置。远端的应答器为了准确的识别局部放电信号从而给脉冲发射器一个信号使其发射一个较大脉冲充当局放反射信号,需要抑制局部放电中的白噪声干扰。介绍了一种基于DSP Builder的局部放电白噪声干扰抑制的实现方法。针对局部放电信号非平稳的特点,基于小波变换对采集到的信号进行阈值去噪处理。FPGA为小波变换提供了较高的计算能力。首先利用DB2小波选取合适层数对局部放电信号按照Mallat算法进行分解获得各层低频系数与高频系数,然后对高频系数进行阈值量化,最后将分解得到的低频系数和经过阈值处理的高频系数进行小波重构。实验结果表明,基于小波变换的阈值去噪可以对局部放电信号中的白噪声有效抑制。
When using the time domain reflection method to locate the local power supply of the high voltage cable,it is necessary to estimate the position of the power supply according to the time difference between the direct signal and the reflected signal of the partial discharge signal.The transponder at the far end needs to suppress the white noise interference in the partial discharge in order to accurately identify the partial discharge signal and give the pulse transmitter a signal to emit a large pulse to act as a PD reflection signal.This paper introduces an implementation method of partial discharge white noise interference suppression based on DSP Builder.According to the non-stationary characteristics of the partial discharge signal,the collected signal is subjected to threshold denoising processing based on wavelet transform.FPGA provides high computational power for wavelet transform.Firstly,the DB2 wavelet is used to select the appropriate number of layers.The partial discharge signal is decomposed according to the Mallat algorithm to obtain the low-frequency coefficients and high-frequency coefficients of each layer,then the high-frequency coefficients are threshold quantized,and the low-frequency coefficients and the high-frequency processed by the threshold are finally decomposed.The coefficients are wavelet reconstructed.The experimental results show that the threshold denoising based on wavelet transform can effectively suppress the white noise in the partial discharge signal.
作者
郑祥
付大赓
Zheng Xiang;Fu Dageng(School of Electrical and Informational Engineering,Dalian Jiaotong University,Dalian 116028,China)
出处
《电子测量技术》
2020年第5期130-133,共4页
Electronic Measurement Technology
关键词
局部放电
应答器
白噪声
小波变换
阈值
partial discharge
transponder
white noise
wavelet transform
threshold
