Geomagnetic storm of 29–31 October 2003: Geomagnetically induced currents and their relation to problems in the Swedish high‐voltage power transmission system

TLDR

On 30 October 2003, a geomagnetic superstorm knocked down part of Sweden's high‑voltage transmission system, with substorms, sudden commencement, and enhanced ionospheric convection creating large geoelectric fields that drove the failure. The study proposes a semideterministic forecasting approach that combines average activity with statistical estimates of GIC fluctuation amplitudes. The three‑phase storm generated extreme geomagnetic activity over Fennoscandia, and the Malmö outage resulted from an abnormal switching state coupled with a low‑set residual overcurrent relay highly sensitive to third‑harmonic currents. The blackout lasted an hour, left 50,000 customers without power, and was the most severe GIC failure since the 1989 Quebec blackout, primarily caused by harmonic distortions from GIC interacting with overly sensitive protective relays.

Abstract

On 30 October 2003, an ongoing geomagnetic superstorm knocked down a part of the high‐voltage power transmission system in southern Sweden. The blackout lasted for an hour and left about 50,000 customers without electricity. The incident was probably the most severe geomagnetically induced current (GIC) failure observed since the well‐known March 1989 Québec blackout. The “three‐phase” storm produced exceptionally large geomagnetic activity at the Fennoscandian auroral region. Although the diversity of the GIC drivers is addressed in the study, the problems in operating the Swedish system during the storm are attributed geophysically to substorms, storm sudden commencement, and enhanced ionospheric convection, all of which created large and complex geoelectric fields capable of driving large GIC. On the basis of the basic twofold nature of the failure‐related geoelectric field characteristics, a semideterministic approach for forecasting GIC‐related geomagnetic activity in which average overall activity is supplemented with statistical estimations of the amplitudes of GIC fluctuations is suggested. The study revealed that the primary mode of GIC‐related failures in the Swedish high‐voltage power transmission system were via harmonic distortions produced by GIC combined with too sensitive operation of the protective relays. The outage in Malmö on 30 October 2003 was caused by a combination of an abnormal switching state of the system and tripping of a low‐set residual overcurrent relay that had a high sensitivity for the third harmonic of the fundamental frequency.