Geomagnetic disturbance storm system impact — A transmission facility owner case study

Federal Energy Regulatory Commission (FERC) Order No. 830 (September 2016) delivered a mandate for reliable transmission system performance during geomagnetic disturbance (GMD) events. In this Order, FERC approved the North American Electric Reliability Corporation (NERC) reliability standard TPL-007-1 (Transmission System Planned Performance for Geomagnetic Disturbance Events). This paper presents the results and conclusions of a transmission facility owner (TFO) system case study. For it, a geomagnetically induced current (GIC) model was developed for a major part of the Alberta Interconnected Electric System (AIES). The main objectives of the study were identifying the transformers most susceptible to high levels of GIC flows and estimating the additional reactive power support to the induced half-cycle saturation triggered by GMD events. Also investigated were: steady-state system security during a GMD event; the need to undertake further studies to more fully investigate GMD event risks; and the need to consider other system components when doing so. The results and conclusions of the study provide a transmission planning approach that complies with NERC TPL-007-1.