Methodology for simulation of geomagnetically induced currents in power systems

Abstract

To assess the geomagnetic hazard to power systems it is useful to be able to simulate the geomagnetically induced currents (GIC) that are produced during major geomagnetic disturbances. This paper examines the methodology used in power system analysis and shows how it can be applied to modelling GIC. Electric fields in the area of the power network are used to determine the voltage sources or equivalent current sources in the transmission lines. The power network can be described by a mesh impedance matrix which is combined with the voltage sources to calculate the GIC in each loop. Alternatively the power network can be described by a nodal admittance matrix which is combined with the sum of current sources into each node to calculate the nodal voltages which are then used to calculate the GIC in the transmission lines and GIC flowing to ground at each substation. Practical calculations can be made by superposition of results calculated separately for northward and eastward electric fields. This can be done using magnetic data from a single observatory to calculate an electric field that is a uniform approximation of the field over the area of the power system. It is also shown how the superposition of results can be extended to use data from two observatories: approximating the electric field by a linear variation between the two observatory locations. These calculations provide an efficient method for simulating the GIC that would be produced by historically significant geomagnetic storm events.

The Influence of Sudden Commencements on the Rate of Change of the Surface Horizontal Magnetic Field in the United Kingdom

“…The exact magnitude of GICs at any given location depends on the precise configuration of the power network, variations in the local ground conductivity, and the rate of change of the surface magnetic field Thomson et al (), Viljanen et al (), Viljanen et al (), Viljanen et al (), D. Boteler (), Beggan (), with larger rates of change of the surface magnetic field driving larger GICs in a given network Bolduc et al (), Viljanen et al (). For example, during the Hydro‐Quebec event in 1989 the maximum ground magnetic field change measured was 479 nT/min, though significant GICs have been observed for values as low as 100 nT/min at other locations Kappenman (), Kappenman ().…”

Comparison of methods for modelling geomagnetically induced currents

“…2a, and the Nodal Admittance Matrix method and the Lehtinen-Pirjola method for circuits as in Fig. 2b (Boteler, 2014;Lehtinen and Pirjola, 1985). The methods based on the type of circuit shown in Fig.…”

North Europe power transmission system vulnerability during extreme space weather

“…For instance, using first principles, Boteler (2014) proposes an efficient method for simulating the GIC produced in a power system during a major GMD. The method is based on power system analysis and Boteler presents how the methods normally used for AC modelling can be adapted to model the quasi-DC GICs.…”

“…Using an extreme 100-year geoelectric field scenario as baseline, the impact of topology changes in the analyzed power grid was investigated to identify critical locations and weaknesses in the system with a view to updating operational procedures and GIC mitigation strategies. Studies using the electromagnetic transient approach for understanding the impact of a GMD were carried out by Gerin-Lajoie et al (2013, 2014. They focus on transformer response resulting from the injection of GICs and propose a set of simulation case studies to illustrate the impact of GICs on voltage regulation in the presence of transformer saturation.…”