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| Titel |
Comparison of methods for modelling geomagnetically induced currents |
| VerfasserIn |
D. H. Boteler, R. J. Pirjola |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 32, no. 9 ; Nr. 32, no. 9 (2014-09-19), S.1177-1187 |
| Datensatznummer |
250121112
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| Publikation (Nr.) |
 copernicus.org/angeo-32-1177-2014.pdf |
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| Zusammenfassung |
| Assessing the geomagnetic hazard to power systems requires reliable modelling
of the geomagnetically induced currents (GIC) produced in the power network.
This paper compares the Nodal Admittance Matrix method with the
Lehtinen–Pirjola method and shows them to be mathematically equivalent. GIC
calculation using the Nodal Admittance Matrix method involves three steps:
(1) using the voltage sources in the lines representing the induced geoelectric
field to calculate equivalent current sources and summing these to obtain the
nodal current sources, (2) performing the inversion of the admittance matrix and
multiplying by the nodal current sources to obtain the nodal voltages, (3) using
the nodal voltages to determine the currents in the lines and in the ground
connections. In the Lehtinen–Pirjola method, steps 2 and 3 of the Nodal Admittance Matrix calculation are combined into one matrix expression. This
involves inversion of a more complicated matrix but yields the currents to
ground directly from the nodal current sources. To calculate GIC in multiple voltage levels of a power system, it is necessary to model the connections
between voltage levels, not just the transmission lines and ground
connections considered in traditional GIC modelling. Where GIC flow to ground
through both the high-voltage and low-voltage windings of a transformer, they
share a common path through the substation grounding resistance. This has
been modelled previously by including non-zero, off-diagonal elements in the
earthing impedance matrix of the Lehtinen–Pirjola method. However, this
situation is more easily handled in both the Nodal Admittance Matrix method
and the Lehtinen–Pirjola method by introducing a node at the neutral point. |
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