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TitleOn the interaction of power transformers and geomagnetically induced currents
AuthorBoteler, D H; Bradley, E
SourceIEEE Transactions on Power Delivery (Institute of Electrical and Electronics Engineers) vol. 31, issue 5, 2016 p. 2188-2195,
Alt SeriesEarth Sciences Sector, Contribution Series 20150239
Mediapaper; on-line; digital
File formatpdf
Subjectsmodelling; geomagnetically induced currents (GIC); transformers; inductance
Illustrationsdiagrams; graphs
ProgramNorthern Canada Geohazards Project, Public Safety Geoscience
AbstractGeomagnetically induced currents (GIC) cause partial saturation of transformers leading to a variety of power system effects. Extensive work has been done to model the transformer response to GIC; however, little consideration has been given to how transformer inductance affects the growth of GIC. Here, we present a new method based on calculating the effective inductance of the transformer experienced by GIC. A step-by-step method is used to calculate each step in the growth of GIC, the fraction of time in saturation, and the effective inductance. The new value of effective inductance is then used to calculate the next step in GIC. Model results for a dc step voltage are in agreement with previously published detailed modelling and show the nonlinear response of transformers. The new technique provides a versatile and fast method for modelling the transformer interaction with GIC and provides a way of assessing the GIC frequencies that need to be considered in assessment of the geomagnetic hazard to a power system.
Summary(Plain Language Summary, not published)
Space weather refers to the dynamic conditions on the Sun and in the space environment, in particular, in the near-Earth environment, that can affect critical infrastructure. NRCan operates the Canadian Space Weather Forecast Centre and conducts research into space weather effects on power systems, pipelines, radio communications and GNSS positioning to help Canadian industry understand and mitigate the effects of space weather. Assessment of geomagnetic hazard requires accurate modeling of the geomagnetically induced currents (GIC) that are expected to occur during a given geomagnetic disturbance (GMD). This paper shows how transformers affect GIC and presents a new method for modelling GIC growth that takes into account the inductance of the transformer.