A study of geomagnetically induced currents in the UK national grid

This thesis examines the effect of geomagnetic disturbances on the UK power system. This is done in two parts. The characteristics of the ground magnetic field across the UK during frequent disturbances are determined. Using the UK Sub-Auroral Magnetometer Network, data are used from substorms during 2000-2003 encompassing solar maximum. Results are compared to a study at higher latitudes during solar minimum and using different substorm detection methods. Similar results are seen, for example mean magnetic variation increases with latitude even in the mid-latitude range and values are approximately double during storm time substorms than those in non- storm time. The results also demonstrate that the difference in substorm detection techniques produces different results when examining characteristics with respect to substorm onset time. Geomagnetic disturbances are a hazard to ground based technology and the second part of this thesis involves the development of a model that computes Geomagnetically Induced Currents in the National Grid arising from geomagnetic disturbances. The model is used with test uniform electric fields to ascertain the effect of the configuration of a power network representative of the UK National I Grid. The model is then combined with magnetometer data and a resistivity model of the UK (constructed by the British Geological Survey) to compute an equivalent electric field during geomagnetic disturbances known to produce GIC at four monitored sites in the National Grid. Modelled GIC are compared to measured data, results identify particular nodes such as In~~t:-Jl..Rueens as areas in the network at risk should a large geomagnetic storm occur. They also show that the simplifications of the modelled grid cause the GIC amplitudes to be larger than recorded. Suggestions of how future work could improve the model are given.EThOS - Electronic Theses Online ServiceGBUnited Kingdo