scholarly journals Geomagnetically induced currents in the New Zealand power network

Space Weather ◽  
2012 ◽  
Vol 10 (8) ◽  
pp. n/a-n/a ◽  
Author(s):  
R. A. Marshall ◽  
M. Dalzell ◽  
C. L. Waters ◽  
P. Goldthorpe ◽  
E. A. Smith
Keyword(s):  
New Zealand ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Induced Currents

scholarly journals Geomagnetically induced currents in the New Zealand power system

2021 ◽  
Author(s):  
Kamran Mukhtar
Keyword(s):  
New Zealand ◽  
High Frequency ◽  
Low Frequency ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Period Range ◽  
The North ◽  
Single Station ◽  
Frequency Components ◽  
Induced Currents

<p><b>This thesis focuses on the use of magnetotelluric (MT) data from both the North Island and South Island of New Zealand to model Geomagnetically Induced Currents (GIC) in the New Zealand power network. The model results have been compared with those from a previously used thin-sheet (TS) conductance model and with measured GIC. </b></p> <p>Initially, a single station modelling approach using a uniform conductivity Earth model is used to model the measured GIC in a transformer at Islington (ISL). This model is further improved by separately modelling low and high frequency components of GIC and then combining these to give full GIC. The model reproduces most of the GIC variations and the correlation coefficient is >70% for major magnetic storms from 2002-2015. As the model reproduces an average response of the network towards geoelectric fields it underestimates the most of extreme GIC. The analysis of GIC from other substations suggests that measured GIC depend on local geoelectric fields and the substation configuration within the network which cannot be captured using a single station approach. These limitations of single station model are addressed using more realistic geoelectric fields based on magnetotelluric data and consideration of the full network. </p> <p>To compute geoelectric fields in the whole network the gaps between MT sites are filled using a Nearest Neighbor interpolation technique. As the northern part of the North Island has no MT data an equivalent circuit approach is followed to model GIC for only the lower part of the network. The MT model GIC are in the period range of 2-30 minutes, based on the available MT data period range. Both the MT and TS techniques are used to compute geoelectric fields and to model GIC for the St. Patrick’s Day storm of 2015 and a 20 November 2003 magnetic storm. Both the MT and TS methods show the same transformers as experiencing large GIC during both storms. The primary difference between the models is that amplitudes of high frequency components of the TS model are significantly smaller than for the MT model. In particular they do not produce large GIC during the sudden storm commencement (SSC) of the St. Patrick’s Day magnetic storm. For the 20 November 2003 storm the TS model effectively reproduces the low frequency components and extreme GIC. The model results show that the North Island power network could be at risk during adverse space weather conditions.</p> <p>Although the South Island has sparser MT data the same technique is used to model SI GIC during both the St. Patrick’s Day and 2003 magnetic storms. Results are compared with measured data from ISL, South Dunedin (SDN) and Halfway Bush (HWB) transformers. The MT model effectively reproduces the measured GIC variations particularly during SSC during the St. Patrick’s Day storm. The TS model gives a very small GIC magnitude during the SSC. During the 20 November 2003 storm both the MT and TS models reproduce strong amplitudes of low frequency components seen in the ISL measured data. </p> <p>Both the MT and TS models show a substantial scale difference between measured and model GIC both for ISL and HWB transformers that needs to be further explored either in terms of better geoelectric interpolation or power network parameters. Overall, the MT model appears much more promising for future GIC modelling, particularly during a sudden storm commencement and for abrupt GIC variations.</p>

scholarly journals Geomagnetically induced currents in the New Zealand power system

2021 ◽  
Author(s):  
Kamran Mukhtar
Keyword(s):  
New Zealand ◽  
High Frequency ◽  
Low Frequency ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Period Range ◽  
The North ◽  
Single Station ◽  
Frequency Components ◽  
Induced Currents

<p><b>This thesis focuses on the use of magnetotelluric (MT) data from both the North Island and South Island of New Zealand to model Geomagnetically Induced Currents (GIC) in the New Zealand power network. The model results have been compared with those from a previously used thin-sheet (TS) conductance model and with measured GIC. </b></p> <p>Initially, a single station modelling approach using a uniform conductivity Earth model is used to model the measured GIC in a transformer at Islington (ISL). This model is further improved by separately modelling low and high frequency components of GIC and then combining these to give full GIC. The model reproduces most of the GIC variations and the correlation coefficient is >70% for major magnetic storms from 2002-2015. As the model reproduces an average response of the network towards geoelectric fields it underestimates the most of extreme GIC. The analysis of GIC from other substations suggests that measured GIC depend on local geoelectric fields and the substation configuration within the network which cannot be captured using a single station approach. These limitations of single station model are addressed using more realistic geoelectric fields based on magnetotelluric data and consideration of the full network. </p> <p>To compute geoelectric fields in the whole network the gaps between MT sites are filled using a Nearest Neighbor interpolation technique. As the northern part of the North Island has no MT data an equivalent circuit approach is followed to model GIC for only the lower part of the network. The MT model GIC are in the period range of 2-30 minutes, based on the available MT data period range. Both the MT and TS techniques are used to compute geoelectric fields and to model GIC for the St. Patrick’s Day storm of 2015 and a 20 November 2003 magnetic storm. Both the MT and TS methods show the same transformers as experiencing large GIC during both storms. The primary difference between the models is that amplitudes of high frequency components of the TS model are significantly smaller than for the MT model. In particular they do not produce large GIC during the sudden storm commencement (SSC) of the St. Patrick’s Day magnetic storm. For the 20 November 2003 storm the TS model effectively reproduces the low frequency components and extreme GIC. The model results show that the North Island power network could be at risk during adverse space weather conditions.</p> <p>Although the South Island has sparser MT data the same technique is used to model SI GIC during both the St. Patrick’s Day and 2003 magnetic storms. Results are compared with measured data from ISL, South Dunedin (SDN) and Halfway Bush (HWB) transformers. The MT model effectively reproduces the measured GIC variations particularly during SSC during the St. Patrick’s Day storm. The TS model gives a very small GIC magnitude during the SSC. During the 20 November 2003 storm both the MT and TS models reproduce strong amplitudes of low frequency components seen in the ISL measured data. </p> <p>Both the MT and TS models show a substantial scale difference between measured and model GIC both for ISL and HWB transformers that needs to be further explored either in terms of better geoelectric interpolation or power network parameters. Overall, the MT model appears much more promising for future GIC modelling, particularly during a sudden storm commencement and for abrupt GIC variations.</p>

scholarly journals Geomagnetically induced currents in the Irish power network during geomagnetic storms

Space Weather ◽  
2016 ◽  
Vol 14 (12) ◽  
pp. 1136-1154 ◽  
Author(s):  
Seán P. Blake ◽  
Peter T. Gallagher ◽  
Joe McCauley ◽  
Alan G. Jones ◽  
Colin Hogg ◽  
...  
Keyword(s):  
Geomagnetic Storms ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Induced Currents

MAG-GIC: Geomagnetically Induced Currents risk hazard in the Portuguese power network

2020 ◽  
Author(s):  
Joana Alves Ribeiro ◽  
Maria Alexandra Pais ◽  
Fernando J. G. Pinheiro ◽  
Fernando A. Monteiro Santos ◽  
Pedro Soares
Keyword(s):  
Solar Cycle ◽  
Geomagnetic Storms ◽  
Power Network ◽  
The South ◽  
Geomagnetically Induced Currents ◽  
Crust And Upper Mantle ◽  
Solar Cycle 24 ◽  
Induced Currents ◽  
Cycle 24 ◽  
Shunt Reactors

&lt;p&gt;The MAG-GIC project has as a main goal to produce the chart of Geomagnetically Induced Currents (GIC) risk hazard in the distribution power network of Portugal mainland.&lt;/p&gt;&lt;p&gt;The study of GICs is important as they represent a threat for infrastructures such as power grids, pipelines, telecommunication cables, and railway systems. A deeper insight into GICs hazard may help in planning and designing more resilient transmission systems and help with criteria for equipment selection.&lt;/p&gt;&lt;p&gt;GICs are a result of variations in the ionospheric and magnetospheric electric currents, that cause changes in the Earth's magnetic field. The Coimbra magnetic observatory (COI) is one of the oldest observatories in operation in the world and the only one in Portugal mainland. It has been (almost) continuously monitoring the geomagnetic field variations since 1866, and in particular, it has registered the imprint of geomagnetic storms during solar cycle 24. Besides the geomagnetic storm signal, which represents the GICs driver, the crust and upper mantle electrical conductivities determine the amplitude and geometry of the induced electric fields.&lt;/p&gt;&lt;p&gt;To present a better approximation of the Earth's conductivity structure below the Portuguese power network, we initiated a campaign to acquire magnetotelluric (MT) data in a grid of 50x50 km all over the territory. Nonetheless, there already exist enough MT data to create a realistic 3D conductivity model in the south of Portugal.&lt;/p&gt;&lt;p&gt;The other important input is the electric circuit for the network grid. We benefit from the collaboration of the Portuguese high voltage power network (REN) company, in providing the grid parameters as resistances and transformer locations, thus allowing us to construct a more precise model. In particular, we implement in our model the effect of shield wires and shunt reactors resistances.&lt;/p&gt;&lt;p&gt;In this study, we present the results of GIC calculations for the south of Portugal for some of the strongest geomagnetic storms in the 20015-17 period recorded at COI during solar cycle 24. We will focus on the sensitivity of results concerning two different conductivity models and different values of the shielding circuit parameters and shunt reactors devices.&lt;/p&gt;

scholarly journals Mitigating the effects of geomagnetically induced currents in the power network

2020 ◽  
Vol 14 (23) ◽  
pp. 5514-5525
Author(s):  
Ali Hesami Naghshbandy ◽  
Arman Ghaderi Baayeh ◽  
Ayda Faraji
Keyword(s):  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Induced Currents

scholarly journals Improved modeling of geomagnetically induced currents in the South African power network

Space Weather ◽  
2008 ◽  
Vol 6 (11) ◽  
pp. n/a-n/a ◽  
Author(s):  
Chigomezyo M. Ngwira ◽  
Antti Pulkkinen ◽  
Lee-Anne McKinnell ◽  
Pierre J. Cilliers
Keyword(s):  
South African ◽  
Power Network ◽  
The South ◽  
Geomagnetically Induced Currents ◽  
Induced Currents

scholarly journals Modelling of geomagnetically induced currents in the Czech transmission grid

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Michal Švanda ◽  
Anna Smičková ◽  
Tatiana Výbošťoková
Keyword(s):  
Wave Model ◽  
Statistical Correlation ◽  
Transmission Network ◽  
Geoelectric Field ◽  
Transmission Power ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Transmission Grid ◽  
Induced Currents ◽  
Low Amplitude

AbstractWe investigate the maximum expected magnitudes of the geomagnetically induced currents (GICs) in the Czech transmission power network. We compute a model utilising the Lehtinen–Pirjola method, considering the plane-wave model of the geoelectric field, and using the transmission network parameters kindly provided by the operator. We find that the maximum amplitudes expected in the nodes of the Czech transmission grid during the Halloween storm-like event are about 15 A. For the “extreme-storm” conditions with a 1-V/km geoelectric field, the expected maxima do not exceed 40 A. We speculate that the recently proven statistical correlation between the increased geomagnetic activity and anomaly rate in the power grid may be due to the repeated exposure of the devices to the low-amplitude GICs. Graphical Abstract

Shield wires effect on GICs in Portuguese power network and design of an instrument to monitor GICs in the transformer neutrals

2021 ◽  
Author(s):  
Rute Santos ◽  
João Cardoso ◽  
M. Alexandra Pais ◽  
Miguel Silva ◽  
Joana Alves Ribeiro ◽  
...  
Keyword(s):  
High Resolution ◽  
Normal Operation ◽  
Raspberry Pi ◽  
Time Interval ◽  
Finite Conductivity ◽  
Power Network ◽  
Geomagnetically Induced Currents ◽  
Electrical Transmission ◽  
Induced Currents ◽  
Current Sensors

&lt;p&gt;Geomagnetically Induced Currents (GICs) are the result of rapid variations in the Earth's geomagnetic field and of the finite conductivity of the Earth. Along grounded conducting structures such as the power grids, the induced electric field drives electric currents in closed circuits. Extreme values of GICs can be a threat to the normal operation of the power system. So, there is an increasing interest in the study of the GICs&amp;#8217; risk and the first step to take is the numerical modelling. In order to model GICs, different factors/parameters must be considered, as the distribution of conductivity, laterally and in depth and characteristics of the different components of the network. These include the values of the different resistances in the power network, the types of transformers and&amp;#160;also&amp;#160;the transmission path for the GICs. Shield wires represent possible paths for GIC currents. In this study the influence of shield wires on GICs in power systems is modelled. Tests were done using realistic values for the circuit parameters provided by the Portuguese high voltage power network company (REN).&lt;/p&gt;&lt;p&gt;The MAG-GIC (Geomagnetically induced currents in Portugal mainland) project has already produced GIC simulations for the South of Portugal. However, there are still no direct records of GICs in the electrical transmission network to validate that model. This study also encompasses the task of producing a measuring instrument to monitor GICs in the neutral of a given transformer. Such an instrument can provide for the measurement and recording of quasi-DC currents with Hall current sensors, with high resolution. It is targeted to operate remotely over a time interval of several months while being minimally invasive to the power transformer (PT). The system relies on LEM high sensitivity closed loop Hall effect current sensors and it is built over a Raspberry Pi 4 Model B platform with a high resolution digitizer (24 bits) expansion board (Waveshare AD/DA). The system also includes temperature monitoring for offset correction. Recorded data are locally stored on a database (InfluxDB) and a wifi interface allows rapid long term trend visualization through a customized dashboard (Grafana).&lt;/p&gt;

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