Objective
Proposed Research Project 2011.
Supervisors: Dr Pierre Cilliers, Dr Lee-Anne McKinnell, SANSA Space Science. Hermanus.
Consultant supervisor: Prof Trevor Gaunt, UCT Electrical Engineering pjcilliers@sansa.org.za
The objective of this study is to develop models for GIC statistics regarding onset time and duration from remote solar parameters with lead times of 1-2 days for selected nodes of the South Africa power system.
The techniques used by Pulkinnen [2010] for a similar study relating to selected nodes in the USA where there are co-located magnetometers and GIC sensors, is te be extended by means of the method of spherical elementary current systems (SECS) to locations in the South African Network for which GIC data is available. The magnetohydrodynamic (MHD) models used by Pulkinnen are available from NASA [CCMC,
URL, 2]. By contrast, the modelling by Pulkinnen required co-located geomagnetic and GIC observations.
The SECS interpolation method allows one to determine the electric field to any location where GIC observations are made,
Background
Intense geomagnetic activity is known to give rise to large geomagnetically induced currents (GICs) in power transmission grids. The South African power network has been damaged by GICs during the previous solar cycle. ESKOM has recently made available measurements of GICs in the South African power network.
Statistical characterization of these measurements and relating them to geomagnetic activity indices provide an efficient and economical way for power transmission system operators to assess GIC risks in retrospective studies [Ngwira, 2011].
Data from the SOHO and STEREO satellites which continually observe the solar corona can provide inputs on the velocity and direction of coronal mass ejections, which are the primary source of GICs in power networks. Inputs from these satellites feed the MHD models to be used in this study.
Bernhardi [2008] applied the SECS method developed by Pulkinnen [Pulkinnen 2008] to interpolate the geoelectric field derived from magnetometer data during a major geomagnetic storm and indicated that uniform plane wave method may not be adequate to account for the observed GICs. Ngwira [Ngwira, 2011] indicated that the error in the estimation of GIC levels increases with increasing distance from the location where the magnetic field is measured and that there may be some directional dependence which relates to the directions from which power lines feed into a transformer substation.
Requirements
This study involves statistical analysis, mathematical modelling and computer programming. The prospective
MSc student should have a background in Physics, Applied Mathematics or Engineering with an interest in geophysics and electrical engineering and experience with MATLAB, Python, IDL or other programming languages. He/she will be hosted in Hermanus at SANSA Space Science for the duration of the study and will be given on-campus accommodation at a nominal fee. The student is expected to present initial research results at SAIP 2011 and endeavour to publish one research paper.
Interested students are encouraged to contact Dr Cilliers.
References
Bernhardi EH, Cilliers PJ, 2008: Improvement in the modelling of geomagnetically induced currents in southern Africa. S. Afr. J. Sci., 104(7 -- 8), 265-- 272.

Ngwira CM, McKinnell LA, Cilliers PJ (2011), Geomagnetic activity indicators of geomagnetically induced current in South Africa, In press in Advances in Space Research, ASR-S-10-00162, 2011
Pulkkinen A., Amm O., Viljanen A. and BEAR working group (2003). Separation of the geomagnetic variation field on the ground into external and internal parts using the spherical elementary current system method.
Earth Planets Space 55, 117 –129.
Pulkkinen A, Taktakishvili A, Odstrcil D and Jacobs W, (2009). Novel approach to geomagnetically induced current forecasts based on remote solar observations, Space Weather, Vol 7, S08005, 2009
The modelled interpolated horizontal electric field over southern Africa at one particular instance on 29
October 2003. The squares represent the locations of the magnetic observatories used to determine the interpolated field [Bernhardi, 2008].