Development of a GIC simulator

This paper describes the development of a system for simulation of the geomagnetically induced currents (GIC) produced in a power system. Magnetic field data or a specified electrojet current are used with an Earth conductivity model to calculate the electric fields at the Earth's surface. These electric field values are used as input to a power system model to give the geomagnetically induced currents throughout the network. Practical calculations can be made by superposition of results calculated separately for northward and eastward electric fields. Superposition can be used with magnetic data from a single observatory for uniform fields, or with data from two observatories assuming a linear variation of the magnetic fields between the two observatory locations. Combining these calculations provides an efficient method for simulating the geomagnetically induced currents produced during any disturbance for which geomagnetic data are available.

I. Introduction

To assess the geomagnetic hazard to power systems requires the ability to simulate the geomagnetically induced currents (GIC) flowing in the power network. Any geomagnetic field variation induces electric fields in the power lines and drive GIC through the power system. However, it is the GIC produced during major disturbances that are of most concern for the power system. A useful test of the hazard to a power system is to calculate the GIC that would be produced by historically significant geomagnetic storm events.