Development of a GIC simulator

A key space weather hazard is the generation of Geomagnetically Induced Currents (GICs) in grounded, conducting infrastructure (e.g., power networks).  These GICs are driven by the changing magnetic field at the surface of the Earth and in extreme cases can cause disruption or even damage to power systems.  Due to a sparsity of GIC measurements around the globe, the rate of change of the magnetic field (e.g., H’) is often used as a proxy, under the assumption that larger rates of change of the geomagnetic field will be related to larger GICs.  While a range of magnetospheric processes can result in large GICs, in this work we focus on one: Sudden Commencements (SCs).  SCs are rapid, coherent changes in the geomagnetic field caused by the impact of a large increase in solar wind dynamic pressure (e.g., an interplanetary shock).  Globally, in one-minute cadence ground magnetic field data SCs appear relatively homogenous, lasting only a few data points.  However, it has previously been found that in New Zealand SCs on the dayside have been linked to 30% larger measured GICs for a given H’.  We investigate a deceptively simple question: why?In this work we examine the sub-minute structure of SCs in New Zealand and their impact on the resulting GICs.  We introduce an analytical model that describes the key features of the magnetic field signature, allowing us to fully describe the key features of an SC.  The use of parameters (e.g., maximum H’) from the fitted analytical model strengthens the correlation between maximum H’ and GIC during SCs, but leaves remnant dependencies which are yet to be explained.  We conduct synthetic experiments with our analytical SC model and a high resolution magnetotelluric-derived map of the southern part of New Zealand to examine which properties of an SC make it more-likely to cause disproportionately large GIC.

This paper presents the preliminary observation on the possible Geomagnetic Induced Current (GIC) activities at Malaysia region during the quiet period of solar cycle 24 (year 2017). In fact, the damage of power system operation might lead to the malfunction of the transformer, which is the main component of the power system. Previously, the cause of the damage has been identified in the long-term investigation, where it drives from the space weather effect so-called (GIC). In this work, the quiet period has been selected by respecting the value of K-Planetary index (Kp) must be less than 3 extracted from OMNIWeb data source. The main objective of the current work is to investigate the behavior of the GIC amplitude at Malaysia region as well as to identify the parameter (ionospheric current and magnetospheric current) that contribute significantly towards the GIC activity at Malaysia region. The type of analysis was carried out using the data of geomagnetic field by extracting the time derivative of the horizontal component (dH/dt) as the indicator for GIC activity. The geomagnetic data was obtained from the MAGDAS observatories at Langkawi (LKW), Perak (PER), and Johor (JOH) stations. Subsequently, the dH/dt value is less than 30 nT/min represent no GIC activity occurred during that particular date for all three stations. However, the results revealed that the ionospheric current, DP2 corresponds well to the dH/dt amplitude. Plus, the latitudinal correlation gave the best representation of the control factor of GIC activity.

GICs is a ground end manifestation associated with the space weather perturbations that should be greatly taken into account by the society. Even though the GICs implication to the power system is not regularly happened, it can cause large scale of system failure. In equatorial, the power system is considered safe since the most intense of geomagnetic storm happened in high latitude. However, the internal damage due to GICs which finally led to the South African power system failure has totally changed the normal perception. Therefore, a preliminary investigation on the GICs activity in equatorial region is performed to understand the space weather impact to the power system. Time derivative of the horizontal magnetic field component (dB/dt) is done to indicate the GICs activity value based on Faraday’s law. All the reported power failures are compiled to produce the threshold value of dB/dt, which possibly cause the harmful effect to the system. Then, dB/dt analysis is extended to show the pattern of GICs activity in function of magnetic latitude and local time. The results reveal that power network in equatorial region has possibly suffered by GIC. Plus, high number of intense GIC activity in this region occurred during dayside.

This paper describes the effect of Geomagnetically Induced Currents (GICs) in single phase-transformer and how to mitigation the phenomena using capacitor at the ground for the transformer, Geomagnetically Induced Currents (GICs) arise from fluctuations in Earth’s magnetic field and can reach alarmingly high levels and cause malfunctions or blackouts in the power grids in which they occur. Under GICs the transformer core suffers a half-cycle saturation its leads to disturbances in the power system, also the design of transformer its impact by GICs. GICs cause some problem in power transformers like heating, burning winding, reactive power consumption and increase odd and even harmonics. Capacitor eliminate the GIC, MATLAB-SIMULINK used to simulate the single-phase transformer.

Geomagnetically Induced Currents (GICs) are low-frequency currents that enter power transmission networks through the grounded-neutral points of the transformer windings. The paper presents a model to emulate the flow of this current. As early as in 1998, GICs studies within the Southern African region focused on demonstrating the existence of GIC in this mid-middle latitude region. Recent literature has amply argued, proved and demonstrated the presence of GICs in the Namibian Transmission Network during a Geomagnetic Disturbance (GMD). Geomagnetic disturbances are perturbations in the magnetosphere which produce variations in the Earth's geomagnetic field, hence leading to flow of GIC in the transmission networks. Since the GICs are DC-like currents they are also essentially referred to as “quasi-DC” currents. Consequently, conventional AC models used in power system studies cannot be used directly to analyse the GIC flow in the electric transmission system, and hence there is need for the development of a working DC model to carry out GMD impact studies on the Namibia Power Network. In this paper, a working quasi-DC model for the Namibia High Voltage (HV) Transmission network is presented. The model is tested via modelling and simulation of GIC flows in the network using the EPRI OpenDSS (Open Distribution Simulation Software). The partial results seem to suggest that the magnitudes of GICs in the network are increasing with the expansion and development of the network since early 2002. The effects of probable network contingencies, based on N-1 Criterion, on the flow of GICs are also presented.

The geoelectric field driving geomagnetically induced currents (GIC) has complex spatial variations. It follows that different patterns of the field vectors in a given area having the same regional mean can produce very different GIC. In this study, we consider a few power grid models and calculate GIC due to a modelled geoelectric field with a regional mean magnitude of 1 V/km. Altogether 8035 snapshots of the electric field are included. We also assume two different ground conductivity models, of which the simpler one consists of two layers across the whole region, and another model has four different two-layer blocks. As a measure of GIC, we use the sum of currents at all substations of the power grid. We also consider the distribution of GIC at a single site. For a given grid, differences between the two ground conductivity models are small. When comparing different power grid models, the sum of GIC varies relatively more for a grid with a small number of substations and transmission lines. When the area and the number of substations increase, the relative difference between the smallest and largest GIC sum decreases. In all cases, assuming a spatially uniform electric field leads to a reasonable estimation of the GIC magnitudes, but it does not produce the largest GIC sum. For a single substation, there is a large variety of GIC values due to different electric field configurations.

Abstract. The geoelectric field drives geomagnetically induced currents (GICs) in technological conductor networks, which can affect the performance of critical ground infrastructure such as electric power transmission grids. The three-dimensional (3-D) electric field at the Earth's surface consists of an external divergence-free (DF) part due to temporally and spatially varying ionospheric and magnetospheric currents, an internal DF part due to temporally and spatially varying telluric currents, and a curl-free (CF) part due to charge accumulation at ground conductivity gradients. We have developed a new method for estimating these contributions. The external and internal parts of the DF electric field are calculated from the time derivative of the external and internal parts of the observed ground magnetic field, respectively, using DF two-dimensional (2-D) spherical elementary current systems (SECSs). The horizontal surface CF electric field is calculated from the known surface DF electric field using coefficients that linearly relate the DF electric field to the CF electric field. The coefficients were obtained from the 3-D induction model PGIEM2G (Polynomial Galerkin Integral Equation Modelling in ElectroMagnetic Geophysics). The calculations are carried out in the time domain, and only two consecutive time steps of the observed magnetic field are needed to compute the surface electric field. The external part of the DF electric field is valid at and below the ionosphere, the internal part at and above the Earth's surface, and the CF part at the Earth's surface. A dense magnetometer network is a requirement for reliable results. The external and internal parts of the DF electric field are generally oppositely directed and have comparable amplitudes, both on the ground and in the ionosphere, indicating that both contributions are significant for the total DF electric field. The largest peaks of the total DF electric field tend to occur when either the external or internal contribution is temporarily suppressed. At a given location, a DF electric field with a given amplitude can result in a total surface electric field amplitude with a difference of orders of magnitude depending on the direction of the DF electric field with respect to the locally dominant conductivity gradient structure. The electric field calculation is computationally light, facilitating operational implementation of a near-real-time 3-D surface electric field monitoring and derivation of long electric field time series.

Geomagnetic disturbances (GMDs) are known to disturb power system equipment performance. The danger is associated with geomagnetically induced currents (GICs) occurring at the Earth's surface during GMD. GICs do not endanger power system operation conditions by themselves. The main challenge posed by GICs to power system states is the change in power system equipment operation conditions provoked by GIC flow. The primary avenue of blackout caused by GMDs is through power transformers. This, in turn, can impair the operation of other power system equipment such as synchronous machines. Modern powerful synchronous machines are not designed and engineered to cope with the negative impacts of GMDs. Moreover, the actual legal norms are inadequate in this case. Enhancing the grid's resiliency to such an event is highly interesting to the industry. The physical processes in synchronous machine windings triggered by GICs and limitations brought to power grid operations are described. First, the idea of the impact of GMDs on the power grid operation is described. The analysis of the impact of GMDs on synchronous machines is performed in the second section. In the end, the power system response under GMDs is studied.

Transformers in New Zealand's South Island electrical transmission network have been impacted by geomagnetically induced currents (GIC) during geomagnetic storms. We explore the impact of GIC on this network by developing a thin‐sheet conductance (TSC) model for the region, a geoelectric field model, and a GIC network model. (The TSC is composed of a thin‐sheet conductance map with underlying layered resistivity structure.) Using modeling approaches that have been successfully used in the United Kingdom and Ireland, we applied a thin‐sheet model to calculate the electric field as a function of magnetic field and ground conductance. We developed a TSC model based on magnetotelluric surveys, geology, and bathymetry, modified to account for offshore sediments. Using this representation, the thin sheet model gave good agreement with measured impedance vectors. Driven by a spatially uniform magnetic field variation, the thin‐sheet model results in electric fields dominated by the ocean‐land boundary with effects due to the deep ocean and steep terrain. There is a strong tendency for the electric field to align northwest‐southeast, irrespective of the direction of the magnetic field. Applying this electric field to a GIC network model, we show that modeled GIC are dominated by northwest‐southeast transmission lines rather than east‐west lines usually assumed to dominate.

Geomagnetically Induced Currents (GICs) are one of the main hazards of Space Weather for modern society since they may lead to electricity blackouts over large regions. The awareness and comprehension of GICs on power systems are the keys to dipping into a more resilient and robust energy system.This study aims to understand the real contribution of shield wires (ShW) in GIC simulations. ShW are protective cables against atmospheric discharges for transmission lines and are commonly connected to the ground at substations and, often, at each supporting pylon. Although ShW represent an additional path for GICs, they are in general not considered in simulations. Possible reasons might be the need for more information on ShW parameters from the transmission system operators, as well as the increase in computational time. But another reason has possibly been the conclusions drawn in preliminary studies, showing that the ShW effect on GICs should be small.By applying the equivalent circuit derived in [1], GIC simulations were obtained for the entire Portuguese power grid using realistic parameters for the grid and a 3D conductivity model. Simulations were carried out using an adaptation of GEOMAGICA [2] by calculating a realistic induced electric field and determining GIC magnitudes in each transformer. Also, more tests were done using the analogue circuit simulator software LTSpice to calculate GIC in the power grid using the induced electric field calculated through GEOMAGICA.Results for different geomagnetic storms are presented and compared with GIC measurements at the transformer neutral in a particular substation of the Portuguese power network. [1] Santos, R., Pais, M. A., Ribeiro, J. A., Cardoso, J., Perro, L., & Santos, A. (2022). Effect of shield wires on GICs: Equivalent resistance and induced voltage sources. International Journal of Electrical Power & Energy Systems, 143, 108487.[2] Bailey, R. L., Halbedl, T. S., Schattauer, I., Römer, A., Achleitner, G., Beggan, C. D., ... & Leonhardt, R. (2017, June). Modelling geomagnetically induced currents in midlatitude Central Europe using a thin-sheet approach. In Annales Geophysicae (Vol. 35, No. 3, pp. 751-761). Copernicus GmbH.

Averages of geomagnetically induced currents (GIC) in the Finnish 400 kV electric power transmission system and the effect of neutral point reactors on GIC

Sweden has experienced many geomagnetically induced current (GIC) events in the past, which is obviously due to the high‐latitude location of the country. The largest GIC, almost 300 A, was measured in southern Sweden in the earthing lead of a 400 kV transformer neutral during the magnetic storm on 6 April 2000. On 30 October 2003, the city of Malmö at the southern coast suffered from a power blackout caused by GIC, leaving 50,000 customers without electricity for about 20–50 min. We have developed a model that enables calculation of GIC in the southern Swedish 400 kV power grid. This work constitutes the first modeling effort of GIC in Sweden. The model is divided into two parts. The electric field is first derived using a ground conductivity model and geomagnetic recordings from nearby stations. The conductivity model is determined from a least squares fit between measured and calculated GIC. GIC are calculated using a power grid model consisting of the topology of the system and of the transformer, transmission line, and station earthing resistances as well as of the coordinates of the stations. To validate the model, we have compared measured and calculated GIC from one site. In total, 24 events in 1998 to 2000 were used. In general the agreement is satisfactory as the correct GIC order of magnitude is obtained by the model, which is usually enough for engineering applications.

Previous studies have demonstrated a close relationship between the time derivative of the horizontal geomagnetic field vector (dH /dt ) and geomagnetically induced currents (GIC) at a nearby location in a power grid. Similarly, a high correlation exists between GIC and the local horizontal geoelectric field (E ), typically modelled from a measured magnetic field.Considering GIC forecasting, it is not feasible to assume that detailed prediction of time series will be possible. Instead, other measures summarising the activity level over a given period are preferable. In this paper, we consider the 30-min maximum of dH /dt or E as a local activity indicator (|dH /dt |30 or |E |30 ). Concerning GIC, we use the sum of currents through the neutral leads at substations and apply its 30-min maximum as a regional activity measure (GIC30 ).We show that |dH /dt |30 at a single point yields a proxy for GIC activity in a larger region. A practical consequence is that if |dH /dt |30 can be predicted at some point then it is also possible to assess the expected GIC level in the surrounding area. As is also demonstrated, |E |30 and GIC30 depend linearly on |dH /dt |30 , so there is no saturation with increasing geomagnetic activity contrary to often used activity indices.

As a result of space weather events, geomagnetically induced currents (GIC) emerge in the power system. These low-frequency currents in the power supply can be thought of as quasi-DC currents. A half-cycle periodic saturation of the core occurs when a DC enters a power transformer. Heating, harmonics, and reactive power losses arise from periodic core saturation. A detailed understanding of power transformer design and performance to determine the exact effect of GIC on power transformers. The paper also provides a succinct explanation of the causes of transformer failure/overheating that have been linked to GIC currents in the published literature. The research shows that, due to the nature of GIC currents, even large levels of GIC would not cause much overheating or damage to the vast majority of power transformers. If subjected to high levels of GIC, only a few specific transformers may experience winding damage due to high winding circulation currents. The report also discusses the underlying problem with GIC, which is the narrow pulse of magnetizing current that occurs when transformer cores are subjected to part-cycle, semi-saturation. We designed or provided such filter to reduce this produced Dc voltages and give Deficient output which is introduced by studying various reviews on GIC in power system transformer by adding GIC effect on the transformer which will add mutually induced DC voltages which does not give proper output as introduces input so we designed or provided such filter to reduce this produced Dc voltages and give Deficient output which is introduced by adding GIC effect on transformer by adding GIC effect on the transformer which will add mutually induced DC voltages which does not give proper output It produces high-quality output and increases the reliability of the system.

<p>We study the ionospheric and ground signatures of geomagnetic activity over Marmara region in Turkey. In our study, we use ionospheric electron density measurements using Dynasonde measured in ITU Campus, Istanbul (41°N, 29°E), magnetic field measurements in İznik (40.43<sup>o</sup>N, 29.72<sup>o</sup>E) and magnetotelluric measurements of magnetic field and electric field in Bozcaada (37.5°N, 106°E). Combined measurements are utilized in search of the geomagnetically induced currents (GICs) and their connection to ionospheric variations for the selected geomagnetic storms. Variations in dB/dt which are used to refer to the GICs are determined and quantified. Accompanying variations in electron density and electric field will be revealed and the deviations from the quiet day will be presented. Although strong GICs are mostly reported to exist over high latitudes, depicted based on the dB/dt variations, we show that they are also present over mid-latitudes where Turkey is located at. At the meeting, we will present our first results based on our measurements and discuss the physical causes of the variations observed.</p>