动态杂散电流干扰下管地电位的波动特征

Fluctuation Characteristics of Pipe-to-Soil Potential under Dynamic Stray Current Interference

在地铁、高铁和高压直流(HVDC)输电系统接地极双极运行引起的动态杂散电流干扰下,现场监测得到196组管地电位数据。在时域上分析了不同干扰下管地电位的动态波动特征,然后利用信号学上连续小波变换(CWT)的方法在频域上研究了不同干扰下管地电位的动态波动特性,统计了不同干扰下管地电位的周期分布范围,并对比了其周期分布的差异。结果表明:三种干扰源都对管道造成动态直流干扰,其中地铁和高铁干扰呈现白天干扰严重、夜间平稳的周期性变化,而HVDC干扰则与高压直流输电系统接地极入地电流的大小与方向有关,没有明显的昼夜差别;高铁交流干扰同时伴随着显著的直流干扰;地铁直流干扰的周期占比随周期增大呈现先增大后减小的趋势,因高铁线路不同,管道干扰的周期分布也有所不同,但主要分布在大于500s的范围,HVDC干扰引起的管地直流电位波动周期分布较为均匀。

196sets of data on pipe-to-soil potential of pipeline under dynamic stray current interference caused by metro,highspeed railway and high voltage direct current(HVDC)transmission system grounding bipolar operation were obtained through field monitoring.The dynamic fluctuation characteristics of pipe-to-soil potential under different interference were analyzed in time domain first,and then in frequency domain by means of continuous wavelet transform(CWT).The periodic distribution ranges of pipe-to-soil potential under different interference were calculated,and the difference of their periodic distribution was compared.The results show that the three interference sources all caused dynamic DC interference to the pipeline.The interference from metro and high-speed railway presented a periodic change of serious during the day and the stable at night,while the interference from HVDC was related to the intensity and direction of the current from grounding electrode in highvoltage transmission line and had no obvious difference between day and night.The AC interference of high-speed railway was accompanied by significant DC interference.The period proportion of metro DC interference increased first and then decreased with the increase of the period.The period distribution of interference to pipeline changed with high-speed railway line,but it was mainly in the range of greater than 500s.The potential fluctuation period of pipe-to-soil DC caused by HVDC interference was evenly distributed.