scholarly journals Comparison of methods for modelling geomagnetically induced currents

2014 ◽  
Vol 32 (9) ◽  
pp. 1177-1187 ◽  
Author(s):  
D. H. Boteler ◽  
R. J. Pirjola
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Matrix Method ◽  
Low Voltage ◽  
Geoelectric Field ◽  
Geomagnetically Induced Currents ◽  
Common Path ◽  
Admittance Matrix ◽  
Induced Currents ◽  
Matrix Expression

Abstract. 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.

scholarly journals The Lehtinen-Pirjola Method Modified for Efficient Modelling of Geomagnetically Induced Currents in Multiple Voltage Levels of a Power Network

2021 ◽  
Author(s):  
Risto J. Pirjola ◽  
David H. Boteler ◽  
Loughlin Tuck ◽  
Santi Marsal
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Efficient Method ◽  
Positive Definite Matrix ◽  
Cholesky Decomposition ◽  
Multiple Time ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Admittance Matrix ◽  
Induced Currents

Abstract. The need for accurate assessment of the geomagnetic hazard to power systems is driving a requirement to model geomagnetically induced currents (GIC) in multiple voltage levels of a power network. The Lehtinen-Pirjola method for modelling GIC is widely used but was developed when the main aim was to model GIC in only the highest voltage level of a power network. Here we present a modification to the Lehtinen-Pirjola (LP) method designed to provide an efficient method for modelling GIC in multiple voltage levels. The LP method calculates the GIC flow to ground from each node. However, with a network involving multiple voltage levels many of the nodes are ungrounded, i.e. have infinite resistance to ground which is numerically inconvenient. The new modified Lehtinen-Pirjola (LPm) method replaces the earthing impedance matrix [Ze] with the corresponding earthing admittance matrix [Ye] in which the ungrounded nodes have zero admittance to ground. This is combined with the network admittance matrix [Yn] to give a combined matrix ([Yn]+[Ye]), which is a sparse symmetric positive definite matrix allowing efficient techniques, such as Cholesky decomposition, to be used to provide the nodal voltages. The nodal voltages are then used to calculate the GIC in the transformer windings and the transmission lines of the power network. The LPm method with Cholesky decomposition also provides an efficient method for calculating GIC at multiple time steps. Finally, the paper shows how software for the LP method can be easily converted to the LPm method and provides examples of calculations using the LPm method.

scholarly journals Modelling geomagnetically induced currents in midlatitude Central Europe using a thin-sheet approach

2017 ◽  
Vol 35 (3) ◽  
pp. 751-761 ◽  
Author(s):  
Rachel L. Bailey ◽  
Thomas S. Halbedl ◽  
Ingrid Schattauer ◽  
Alexander Römer ◽  
Georg Achleitner ◽  
...  
Keyword(s):  
Power Systems ◽  
Geomagnetic Storms ◽  
Thin Sheet ◽  
Geoelectric Field ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Variations ◽  
Detailed Surface ◽  
Short Period ◽  
Long Time ◽  
Induced Currents

Abstract. Geomagnetically induced currents (GICs) in power systems, which can lead to transformer damage over the short and the long term, are a result of space weather events and geomagnetic variations. For a long time, only high-latitude areas were considered to be at risk from these currents, but recent studies show that considerable GICs also appear in midlatitude and equatorial countries. In this paper, we present initial results from a GIC model using a thin-sheet approach with detailed surface and subsurface conductivity models to compute the induced geoelectric field. The results are compared to measurements of direct currents in a transformer neutral and show very good agreement for short-period variations such as geomagnetic storms. Long-period signals such as quiet-day diurnal variations are not represented accurately, and we examine the cause of this misfit. The modelling of GICs from regionally varying geoelectric fields is discussed and shown to be an important factor contributing to overall model accuracy. We demonstrate that the Austrian power grid is susceptible to large GICs in the range of tens of amperes, particularly from strong geomagnetic variations in the east–west direction.

Variation Characteristics of Geoelectric Field in Mid-to-Low Latitude Area during Geomagnetic Storms

2014 ◽  
Vol 1008-1009 ◽  
pp. 524-529
Author(s):  
Ping Liu ◽  
Chun Ming Liu ◽  
Lian Guang Liu
Keyword(s):  
Power Systems ◽  
Space Weather ◽  
Transmission Lines ◽  
Geomagnetic Storms ◽  
System Component ◽  
Geoelectric Field ◽  
Geomagnetically Induced Currents ◽  
Low Latitude ◽  
Variation Characteristics ◽  
East West

Large geoelectric field generated in the ground during severe space weather events are sources of geomagnetically induced currents (GICs), which flow in power systems potentially causing damage to system component or failure of the system. In this paper, based on the H and D components of the recent geomagnetic storm data measured at 10 mid-to-low latitude geomagnetic observatories, we analyzed the variation characteristics of the amplitude of north-south and east-west geoelectric components with geographic latitudes. Furthermore, we discussed the possibilities of GIC problem occurrence in transmission lines in different directions at different latitude in China. The result shows that transmission lines in east-west direction at higher latitude are more susceptible to space weather hazard. And it will contribute to the assessment of geomagnetic hazard to power systems and the control of GIC in the current and future power grids in China.

scholarly journals An Approach to Model Earth Conductivity Structures with Lateral Changes for Calculating Induced Currents and Geoelectric Fields during Geomagnetic Disturbances

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Bo Dong ◽  
Zezhong Wang ◽  
Risto Pirjola ◽  
Chunming Liu ◽  
Lianguang Liu
Keyword(s):  
Power Systems ◽  
Electric Fields ◽  
Three Dimensional ◽  
Geoelectric Field ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Disturbances ◽  
Planar Grid ◽  
Induced Currents ◽  
Telluric Currents ◽  
Earth Conductivity

During geomagnetic disturbances, the telluric currents which are driven by the induced electric fields will flow in conductive Earth. An approach to model the Earth conductivity structures with lateral conductivity changes for calculating geoelectric fields is presented in this paper. Numerical results, which are obtained by the Finite Element Method (FEM) with a planar grid in two-dimensional modelling and a solid grid in three-dimensional modelling, are compared, and the flow of induced telluric currents in different conductivity regions is demonstrated. Then a three-dimensional conductivity structure is modelled and the induced currents in different depths and the geoelectric field at the Earth’s surface are shown. The geovoltages by integrating the geoelectric field along specific paths can be obtained, which are very important regarding calculations of geomagnetically induced currents (GIC) in ground-based technical networks, such as power systems.

scholarly journals Impulsive disturbances of the geomagnetic field as a cause of induced currents of electric power lines

2019 ◽  
Vol 9 ◽  
pp. A18 ◽  
Author(s):  
Vladimir Belakhovsky ◽  
Vyacheslav Pilipenko ◽  
Mark Engebretson ◽  
Yaroslav Sakharov ◽  
Vasily Selivanov
Keyword(s):  
Electric Power ◽  
Transmission Lines ◽  
Geomagnetic Field ◽  
Energy Yield ◽  
Interplanetary Shocks ◽  
Geomagnetically Induced Currents ◽  
Ionospheric Currents ◽  
Geomagnetic Variations ◽  
Electric Power Line ◽  
Induced Currents

Geomagnetically induced currents (GICs) represent a significant challenge for society on a stable electricity supply. Space weather activates global electromagnetic and plasma processes in the near-Earth environment, however, the highest risk of GICs is related not directly to those processes with enormous energy yield, but too much weaker, but fast, processes. Here we consider several typical examples of such fast processes and their impact on power transmission lines in the Kola Peninsula and in Karelia: interplanetary shocks; traveling convection vortices; impulses embedded in substorms; and irregular Pi3 pulsations. Geomagnetic field variability is examined using data from the IMAGE (International Monitor for Auroral Geomagnetic Effects) magnetometer array. We have confirmed that during the considered impulsive events the ionospheric currents fluctuate in both the East-West and North-South directions, and they do induce GIC in latitudinally extended electric power line. It is important to reveal the fine structure of fast geomagnetic variations during storms and substorms not only for a practical point of view but also for a fundamental scientific view.

scholarly journals Prediction of geomagnetically induced currents (GICs) flowing in Japanese power grid for Carrington-class magnetic storms

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Yusuke Ebihara ◽  
Shinichi Watari ◽  
Sandeep Kumar
Keyword(s):  
Transmission Lines ◽  
Power Grid ◽  
Magnetic Storms ◽  
Power Grids ◽  
Geomagnetically Induced Currents ◽  
Geomagnetic Disturbances ◽  
Low Latitude ◽  
Solar Eruptions ◽  
Induced Currents ◽  
Extra High Voltage

AbstractLarge-amplitude geomagnetically induced currents (GICs) are the natural consequences of the solar–terrestrial connection triggered by solar eruptions. The threat of severe damage of power grids due to the GICs is a major concern, in particular, at high latitudes, but is not well understood as for low-latitude power grids. The purpose of this study is to evaluate the lower limit of the GICs that could flow in the Japanese power grid against a Carrington-class severe magnetic storm. On the basis of the geomagnetic disturbances (GMDs) observed at Colaba, India, during the Carrington event in 1859, we calculated the geoelectric disturbances (GEDs) by a convolution theory, and calculated GICs flowing through transformers at 3 substations in the Japanese extra-high-voltage (500-kV) power grid by a linear combination of the GEDs. The estimated GEDs could reach ~ 2.5 V/km at Kakioka, and the GICs could reach, at least, 89 ± 30 A near the storm maximum. These values are several times larger than those estimated for the 13–14 March 1989 storm (in which power blackout occurred in Canada), and the 29–31 October 2003 storm (in which power blackout occurred in Sweden). The GICs estimated here are the lower limits, and there is a probability of stronger GICs at other substations. The method introduced here will be immediately applicable for benchmark evaluation of low-latitude GICs against the Carrington-class magnetic storms if one assumes electrical parameters, such as resistance of transmission lines, with sufficient accuracy.

Insight into impact of geomagnetically induced currents on power systems: Overview, challenges and mitigation

2020 ◽  
pp. 106927
Author(s):  
Vipul N. Rajput ◽  
David H. Boteler ◽  
Nishil Rana ◽  
Mahenaj Saiyed ◽  
Smit Anjana ◽  
...  
Keyword(s):  
Power Systems ◽  
Geomagnetically Induced Currents ◽  
Induced Currents ◽  
Insight Into

scholarly journals Diagnostics of geomagnetically-induced currents in high-tension electric transmission lines

2019 ◽  
Vol 127 ◽  
pp. 02008
Author(s):  
Vladimir Sivokon ◽  
Nina Cherneva ◽  
Evgeniy Malkin
Keyword(s):  
Transmission Lines ◽  
Power Distribution ◽  
Geomagnetically Induced Currents ◽  
Electric Transmission ◽  
The Earth ◽  
Electric Transmission Lines ◽  
High Tension ◽  
Earth Magnetic Field ◽  
Induced Currents ◽  
Even Harmonics

The problem of geomagnetically-induced currents (GIC) effect on electrotechnical systems is topical as long as uninterrupted power distribution is critically important for all the spheres of human activity. Our investigations showed the possibility of GIC diagnostics based on the estimates of industrial current higher harmonics and showed that even harmonics correlate with the Earth magnetic field changes in a greater degree. However, the measurements carried out in 220 V network showed low and not always univocal correlation of the processes. Thus, we propose a technique for diagnostics of geomagnetically-induced currents in high-tension electric transmission lines**.

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