In some areas, there is no stray current interference caused by industrial equipment, and the pipe ground potential / pipeline current is still changing occasionally on the buried pipeline. This change is often related to the stray current disturbance caused by the occasional geomagnetic disturbance.
The earth's magnetic field is greatly affected by the solar wind. The sunspot activity causes the change of the solar wind intensity, which makes the earth's magnetic field deform accordingly. As a result, the geomagnetic field changes and migrates strongly with time. The magnetometer commonly used in geophysical observation can be used to measure the change of geomagnetic field.
Due to the change of geomagnetic field, the strong electric characteristics of soil field change, which is related to the geological conditions and soil resistivity. Especially in the conductive layer in the rocky zone, the change can be as high as 0.1v/km. The disturbance of geomagnetic field will affect the voltage and current on the buried metal structure. During the period of intense sunspot activity, it has been observed that this effect is very strong.
It is generally believed that this effect is very important close to the polar region and cannot be ignored. The pipeline with good anti-corrosion coating can behave as an equipotential line in this electric field, and different pipe ground potentials can be measured at its two ends. As a result, polarization current will be generated at the defect position of pipeline anticorrosive coating; the greater the leakage of pipeline, the greater the polarization current flowing through the pipeline caused by the change of geomagnetic field. In the pipeline with cathodic protection, the polarization current is superimposed with the cathodic protection current, which will increase or decrease it.
Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services.