Space weather events in July 1982 and October 2003 and the effects of geomagnetically induced currents on Swedish technical systems

The EURISGIC project (European Risk from Geomagnetically Induced Currents) aims at deriving statistics of geomagnetically induced currents (GIC) in the European high-voltage power grids. Such a continent-wide system of more than 1500 substations and transmission lines requires updates of the previous modelling, which has dealt with national grids in fairly small geographic areas. We present here how GIC modelling can be conveniently performed on a spherical surface with minor changes in the previous technique. We derive the exact formulation to calculate geovoltages on the surface of a sphere and show its practical approximation in a fast vectorised form. Using the model of the old Finnish power grid and a much larger prototype model of European high-voltage power grids, we validate the new technique by comparing it to the old one. We also compare model results to measured data in the following cases: geoelectric field at the Nagycenk observatory, Hungary; GIC at a Russian transformer; GIC along the Finnish natural gas pipeline. In all cases, the new method works reasonably well.

Section: Introductionmentioning

confidence: 99%

Continental scale modelling of geomagnetically induced currents

Viljanen

Pirjola

Wik³

et al. 2012

“…Predictions of the strength and time variations of magnetic substorms have not yet reached a mature level for practical applications although post-event analyses have reached a high level of accuracy (e.g., Wik et al 2008Wik et al , 2009. General warnings of magnetic storm conditions following solar outbursts (CMEs) are provided by satellite data.…”

Section: Discussionmentioning

confidence: 99%

“…In both cases the management of the power grid by the Swedish power company, ''Vattenfallet'', prevented further adverse consequences of the high-voltage power line cuts. The effects on consumers in Sweden were small and no effects were recorded in the coupled power grids in the neighboring countries, Finland, Norway, and Denmark during these storms (e.g., Stauning 2001;Stauning & Watermann 2002;Wik et al 2008Wik et al , 2009). …”

Section: Power Grid Disturbancesmentioning

confidence: 99%

“…Power grids, in reality, are constructed as twodimensional networks with grounding connections at many grid points. However, it is possible (but complicated) to model GIC effects in real power systems with adequate accuracy (e.g., Viljanen & Pirjola 1989;Pulkkinen et al 2005;Wik et al 2008Wik et al , 2009. For the present purpose it suffices to state that the geoelectric field strengths and thus the intensities of GIC depend on the strength and variability of the ionospheric currents -in the simplest approximation expressed through the time derivative dB/dt of the variable magnetic field generated at ground level by the ionospheric currents (e.g., Viljanen et al 2001).…”

Section: Ionospheric Currents and Gic Eventsmentioning

confidence: 99%

See 1 more Smart Citation

Power grid disturbances and polar cap index during geomagnetic storms

Stauning

2013

The strong geomagnetic storm in the evening of 30 October 2003 caused high-voltage power grid disturbances in Sweden that expanded to produce hour-long power line outage in Malmö located in the southern part of the country. This was not a unique situation. The geomagnetic storm on 13 March 1989 caused extensive disruptions of high-voltage power circuits especially in the Province of Quebec, Canada, but also to a lesser degree in Scandinavia. Similar events have occurred earlier, among others, during the great storms of 13-14 July 1982 and 8-9 February 1986. These high-voltage power grid disturbances were related to impulsive magnetic variations accompanying extraordinarily intense substorm events. The events were preceded by lengthy intervals of unusually high values of the Polar Cap (PC) index caused by enhanced transpolar ionospheric convection. The transpolar convection transports magnetic flux from the dayside to nightside which causes equatorward displacements of the region of auroral activity enabling the substorms to hit vital power grids. During the 30 October 2003 event the intense solar proton radiation disabled the ACE satellite observations widely used to provide forecast of magnetic storm events. Hence in this case the alarmingly high PC index could provide useful warning of the storm as a back-up of the missing ACE-based forecast. In further cases, monitoring the PC index level could provide supplementary storm warnings to the benefit of power grid operators.

“…Large GIC are usually considered to occur at high latitudes such as North America and Scandinavia, where tripping problems and even blackouts of power systems due to GIC have been experienced (Bolduc 2002;Pulkkinen et al 2005;Wik et al 2009). Large currents in transformer neutrals have been monitored in the Chinese high-voltage power system many times during geomagnetic storms although China is a midlow-latitude country.…”

Section: Introductionmentioning

confidence: 99%

Observations and modeling of GIC in the Chinese large-scale high-voltage power networks

Liu

Pirjola

2014

During geomagnetic storms, the geomagnetically induced currents (GIC) cause bias fluxes in transformers, resulting in half-cycle saturation. Severely distorted exciting currents, which contain significant amounts of harmonics, threaten the safe operation of equipment and even the whole power system. In this paper, we compare GIC data measured in transformer neutrals and magnetic recordings in China, and show that the GIC amplitudes can be quite large even in mid-low latitude areas. The GIC in the Chinese Northwest 750 kV Power Grid are modeled based on the plane wave assumption. The results show that GIC flowing in some transformers exceed 30 A/phase during strong geomagnetic storms. GIC are thus not only a high-latitude problem but networks in middle and low latitudes can be impacted as well, which needs careful attention.