特高压直流电晕电流数据的降噪方法研究

Research of UHVDC corona current data de-noising method

特高压直流输电线路电晕特性的研究对于降低电晕效应、运行损耗和环境影响等都具有十分重要的意义。在国家电网公司特高压直流试验基地,利用特高压直流试验线段和户外大电晕笼,对宽频域电晕电流测量系统获得的正极电晕电流数据进行处理研究。由于该系统为户外作业,空间辐射、机械振动、线路传输等因素都将带来噪声,使得采集到的数据中噪声含量非常丰富,有用的电晕电流信号与噪声同时并存,所以研究电晕特性时首先要对电晕电流数据进行降噪处理。以小波阈值降噪方法为核心,结合快速傅里叶变换及多频陷波滤波技术对电晕电流数据进行降噪处理。仿真实验结果表明,提出的降噪算法效果明显,可实现强噪声背景下电晕电流信号的有效提取,能够为特高压直流电晕特性的深入研究打下很好的基础。

It is highly significant for researching the corona characteristics of ultra high voltage direct current （UHVDC） transmission lines to reduce the corona effect,operating loss and environmental impact. In the UHVDC test base of State Grid Corporation of China （SGCC）, the broadband domain corona current measurement system, which uses the UHVDC test segments and large outdoor corona cage as the research object,is put into operation to collect corona current data. Because the system is operating in outdoor conditions, a variety of factors, such as space radiation, mechanical vibration,line transmission and so on,would bring noise signal into the data and make the noise content rich and the useful corona current signal is submerged in the background noise. Therefore,the noise reduction processing of corona current data will be first before the research of corona characteristics. In this paper, the wavelet threshold noise reduction methods,combined with the fast Fourier transform （FFT） and digital multiple notch filtering techniques,are used in noise reduction processing of corona current data. And the simulation results showed that the noise reduction effect is obvious,and the corona current signal is effectively extracted in the context of strong noise. This study will provide the preliminary basis for the research of corona characteristics of UHVDC transmission project.