城镇环境中PCM信号选择对防腐层检测的影响

多频管中电流法(PCM)是防腐层检测和评价的一种有效的方法,在使用PCM对防腐层进行检测时,如果遇到干扰信号会对检测结果造成很大的影响。阐述PCM的检测原理,分析不同测量信号对测量结果的影响,进行了4 Hz和128 Hz测量信号的对照组检测实验。城镇环境中,干扰信号比较复杂,特别是低频干扰信号,会对4 Hz的PCM检测信号产生相互叠加或者抵消,使检测和评价结果偏离真实情况。在城镇燃气管道的PCM检测中,应该优先使用128 Hz或者更高频率的信号,这样能够在一定程度上排除外界干扰,使检测结果更加准确。

Effect of PCM Signal Selection on Anticorrosive Coating Detection in Urban Environment

The pipeline current mapper （PCM） is an effective method for anticorrosive coating detec- tion and evaluation. If interference signal is encounted, the detection results can be significantly affected when PCM is used to detect the anticorrosive coating. The detection principle of PCM is elaborated, the influence of different measurement signals on the measurement result is analyzed, and the detection experiments of the control group for 4 Hz and 128 Hz measurement signals are conducted. The interference signals are more com- plex in the urban environment, especially low frequen- cy interference signals can cause 4 Hz PCM detection signal superposition or offset each other, which devi- ates the detection and evaluation results from the real situation. 128 Hz or higher frequency signal should be used preferably, which can remove external interfer- ence to some extent to make the detection results more accurate in the detection of city gas pipeline by PCM.