Recent advances and validation of GIC modelling in the UK

Richardson, Gemma; Beggan, Ciaran; Thomson, Alan. 2017 Recent advances and validation of GIC modelling in the UK. [Speech] In: 14th European Space Weather Week, Oostende, Belgium, 27 Nov - 1 Dec 2017. (Unpublished)

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Official URL: http://www.stce.be/esww14/

Abstract/Summary

We present a major upgrade to the power network model for the mainland UK and provide a validation of it with respect to both measured and synthetic data. Although we have only limited measured geomagnetically induced current (GIC) data with which to verify fully this updated model, we present an investigation of the sensitivity or accuracy of the model at each step in the modelling process: (1) The input geomagnetic field – we investigate the variability in modelled substation GIC with respect to network distance from magnetic field measurements made at magnetic observatories. (2) The electric field calculation - we use electric field measurements at the three UK observatories to test both the code and conductivity model used to compute the electric field across the UK. (3) The estimation of GICs in the power network - we use the test network provided by Horton et al. (2012), to test our modelling methodology and to validate the code at the GIC calculation step using a uniform electric field. (4) As a final step, we compare the output from the complete modelling chain with a small set of GIC measurements available for the March 2015 storm. We find that magnetic field measurements from observatories within a few hundred kilometres of the network can be used to estimate GIC within 30-40% of the true value; whilst observatories that are further away are less reliable, underestimating the largest values and recording false extremes. We also find good agreement between modelled and measured electric fields and GIC, giving us confidence that our models are providing sensible estimates of GIC. This research has benefitted from support from Natural Environment Research Council grant number NE/P017231/1.