Research On PSP Interference Effect Of Geomagnetic Storm On Gas And Oil Pipeline

Gas and oil pipeline are buried under ground with insulating coats on both the inner and outer surfaces of the steel pipeline and it can avoid direct contact with the soil. Therefore, its interfering and responding mechanism under the geomagnetic storm is different from that in the power grid, and it is of great importance to analyze the danger and protection of pipeline under geomagnetic storm through studying such interfering mechanism, physical process, modeling, algorithm and interference effect. This paper expatiates the mechanism and process of pipe-soil potentials (PSP) which is produced by geomagnetically induced current (GIC) induced in gas and oil pipeline. Examples are analyzed based on 2 events of geomagnetic storms induced PSP phenomenon spotted in Gang-Qing pipeline and Shan-Jing pipeline No.2 on October 1st,2012 and February 28th,2014 respectively. GIC and PSP induced in the pipeline during the geomagnetic storm are closely related to magnetic storm intensity, earth construction and morphological structures of pipeline and so on. Through building a subarea layered-earth and one-dimensional conductivity model, calculating method of earth electric field and pipeline electric field based on the plane wave method were obtained, and algorithm of the GIC and PSP in the pipeline based on DSTL theory was derived. Then hazard in project of natural gas and oil pipeline from West to East China under geomagnetic storm were calculated and analyzed to illustrate feasibility and validity of this modeling and algorithm for GIC and PSP. Using this approved method and under the assumption of an induced electric field of 0.1V/km along the same direction as the pipeline, the effect of different forms and structures of pipeline to PSP level are calculated and analyzed, then laws and characteristics are summarized. According to that, dangerous spots of pipeline under geomagnetic storm are given and hazards brought to cathodic protection and personal safety are analyzed. Through comparing pipeline with hazard and protection of power grid under geomagnetic storm, preliminary prevention and governance are given. The monitored data and calculation results suggest that dangerous spots of pipeline under geomagnetic storm are different based on the diverse forms and structures of pipeline and weak and medium geomagnetic storms need to be taken into consideration in future researches on interference and protection of pipeline. This provides important basis to protection study of gas and oil pipeline under geomagnetic storm.