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Modeling the geomagnetic induction in pipeline networks is essential for the risk assessment and management of geomagnetic disturbances. The induced geoelectric field (GEF) is usually spatially nonuniform, depending on the distribution of the geomagnetic variation and the earth conductivity. However, few studies have been conducted on the induction in complex pipeline networks with nonuniform GEF. In this article, a calculation model for induction in pipeline networks with nonuniform GEF is proposed by utilizing the modified equivalent-pi circuits. Then, the proposed model is used to investigate the distribution of pipe-to-soil potentials and geomagnetically induced currents in the pipeline network under several typical nonuniform GEF scenarios due to geomagnetic source fields, including local enhancement and spatially gradual variation. Furthermore, taking the coast effect as a typical case, the influence of the lateral variation of earth conductivity on the induction is analyzed. The results show that the nonuniform GEF may greatly affect the induction results in the local parts of the pipeline network. [ABSTRACT FROM AUTHOR]

Calculation of geomagnetically induced current (GIC) flowing through power system during the geomagnetic storm has attracted more attention recently. However, for high voltage power systems with transmission lines over hundreds or even thousands of kilometers, the earth model and geomagnetical field generally vary significantly. So, it is essential to take them into consideration using limited earth survey sites and geomagnetic observatories. To address this problem, a Kriging method is introduced in this paper to make earth model and geomagnetical field interpolations. It has the characteristic of spatial autocorrelation by considering not only the distances between predicted points and training points but also the distances between training points themselves. Finally, a case study of the Central China 1000 kV ultra-high voltage (UHV) grid is carried out to illustrate the applicability and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Geo-magnetically induced currents (GICs) have attracted more attention since many Ultra-High Voltage (UHV) transmission lines have been built, or are going to be built in the world. However, when calculating GICs based on the classical model, some input parameters, such as the earth conductivity and dc resistances of the grid, are uncertain or very hard to be determined in advance. Taking this into account, the uncertainty quantification (UQ) model of the geo-electric fields and GICs is proposed in this paper. The UQ of the maximums of the geo-electric fields and GICs during storms is carried out based on the polynomial chaos (PC) method. The results of the UHV grid, 1000 kV Sanhua Grid, were presented and compared to the Monte Carlo method. The total Sobol indices are calculated by using the PC expansion coefficients. The sensitivities of geo-electric fields and GICs to the input variables are analyzed based on the total Sobol indices. Results show that the GICs and geo-electric fields can be effectively simulated by the proposed model, which may offer a better understanding of the sensitivities to input uncertain variables and further give a reasonable evaluation of the geomagnetic threat to the grid. [ABSTRACT FROM AUTHOR]