Characteristics and effects of electromagnetic interference from UHVDC and geomagnetic storms on buried pipelines

摘要

The influence of +/- 800 kV ultra-high voltage direct current (UHVDC) transmission monopole operation on buried oil pipelines was compared between the 6250 A grounding pole current conditions of the ZaluteQingzhou Project on December 24, 2017 and the Shanghai Temple-Shandong Project on January 2, 2017. Besides, the influence of geomagnetic storms on the safety of buried oil pipelines were also analyzed based on monitoring data from the geoelectric field of the China Anqiu geomagnetic station on September 9 and 29, 2017. The results show that the influence of the DC grounding pole current on the pipeline is related to the distance between the ground electrode and the pipeline, the operating state of the potentiostat, and the spacing of the insulating flange on the pipeline. The geomagnetically induced current and pipe-soil potential offsets for the geomagnetic storm intruding the pipeline are related to the rate of change for the geomagnetic field. There are differences in the stray current and PSP generation mechanisms for the intruded pipeline caused by the two interference sources: the intensity and influence range of the interference source, and the annual average corrosion rate of the pipeline. Compared with the DC grounding pole current, the geomagnetic storm has a greater interference effect on buried pipelines.